acquired immunodeficiency syndrome

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AIDS

Definition

Acquired immune deficiency syndrome (AIDS) is an infectious disease caused by the human immunodeficiency virus (HIV). It was first recognized in the United States in 1981. AIDS is the advanced form of infection with the HIV virus, which may not cause recognizable disease for a long period after the initial exposure (latency). No vaccine is currently available to prevent HIV infection. At present, all forms of AIDS therapy are focused on improving the quality and length of life for AIDS patients by slowing or halting the replication of the virus and treating or preventing infections and cancers that take advantage of a person's weakened immune system.

Description

AIDS is considered one of the most devastating public health problems in recent history. In June 2000, the Centers for Disease Control and Prevention (CDC) reported that 120,223 (includes only those cases in areas that have confidential HIV reporting) in the United States are HIV-positive, and 311,701 are living with AIDS (includes only those cases where vital status is known). Of these patients, 44% are gay or bisexual men, 20% are heterosexual intravenous drug users, and 17% are women. In addition, approximately 1,000-2,000 children are born each year with HIV infection. The World Health Organization (WHO) estimates that 33 million adults and 1.3 million children worldwide were living with HIV/AIDS as of 1999 with 5.4 million being newly infected that year. Most of these cases are in the developing countries of Asia and Africa.

Risk of acquiring HIV infection by entry site
Entry site Risk virus
reaches entry
site
Risk virus
enters
Risk
inoculated
Conjuntiva Moderate Moderate Very low
Oral mucosa Moderate Moderate Low
Nasal mucosa Low Low Very low
Lower
respiratory
Very low Very low Very low
Anus Very high Very high Very high
Skin, intact Very low Very low Very low
Skin, broken Low High High
Sexual:
Vagina Low Low Medium
Penis High Low Low
Ulcers (STD) High High Very high
Blood:
Products High High High
Shared needles High High Very High
Accidental needle Low High Low
Traumatic wound Modest High High
Perinatal High High High

Risk factors

AIDS can be transmitted in several ways. The risk factors for HIV transmission vary according to category:

  • Sexual contact. Persons at greatest risk are those who do not practice safe sex, those who are not monogamous, those who participate in anal intercourse, and those who have sex with a partner with symptoms of advanced HIV infection and/or other sexually transmitted diseases (STDs). In the United States and Europe, most cases of sexually transmitted HIV infection have resulted from homosexual contact, whereas in Africa, the disease is spread primarily through sexual intercourse among heterosexuals.
  • Transmission in pregnancy. High-risk mothers include women married to bisexual men or men who have an abnormal blood condition called hemophilia and require blood transfusions, intravenous drug users, and women living in neighborhoods with a high rate of HIV infection among heterosexuals. The chances of transmitting the disease to the child are higher in women in advanced stages of the disease. Breast feeding increases the risk of transmission by 10-20%. The use of zidovudine (AZT) during pregnancy, however, can decrease the risk of transmission to the baby.
  • Exposure to contaminated blood or blood products. With the introduction of blood product screening in the mid-1980s, the incidence of HIV transmission in blood transfusions has dropped to one in every 100,000 transfused. With respect to HIV transmission among drug abusers, risk increases with the duration of using injections, the frequency of needle sharing, the number of persons who share a needle, and the number of AIDS cases in the local population.
  • Needle sticks among health care professionals. Present studies indicate that the risk of HIV transmission by a needle stick is about one in 250. This rate can be decreased if the injured worker is given AZT, an anti-retroviral medication, in combination with other medication.

HIV is not transmitted by handshakes or other casual non-sexual contact, coughing or sneezing, or by bloodsucking insects such as mosquitoes.

AIDS in women

AIDS in women is a serious public health concern. Women exposed to HIV infection through heterosexual contact are the most rapidly growing risk group in the United States population. The percentage of AIDS cases diagnosed in women has risen from 7% in 1985 to 23% in 1999. Women diagnosed with AIDS may not live as long as men, although the reasons for this finding are unclear.

AIDS in children

Since AIDS can be transmitted from an infected mother to the child during pregnancy, during the birth process, or through breast milk, all infants born to HIV-positive mothers are a high-risk group. As of 2000, it was estimated that 87% of HIV-positive women are of childbearing age; 41% of them are drug abusers. Between 15-30% of children born to HIV-positive women will be infected with the virus.

AIDS is one of the 10 leading causes of death in children between one and four years of age. The interval between exposure to HIV and the development of AIDS is shorter in children than in adults. Infants infected with HIV have a 20-30% chance of developing AIDS within a year and dying before age three. In the remainder, AIDS progresses more slowly; the average child patient survives to seven years of age. Some survive into early adolescence.

Causes and symptoms

Because HIV destroys immune system cells, AIDS is a disease that can affect any of the body's major organ systems. HIV attacks the body through three disease processes: immunodeficiency, autoimmunity, and nervous system dysfunction.

Immunodeficiency describes the condition in which the body's immune response is damaged, weakened, or is not functioning properly. In AIDS, immunodeficiency results from the way that the virus binds to a protein called CD4, which is primarily found on the surface of certain subtypes of white blood cells called helper T cells or CD4 cells. After the virus has attached to the CD4 receptor, the virus-CD4 complex refolds to uncover another receptor called a chemokine receptor that helps to mediate entry of the virus into the cell. One chemokine receptor in particular, CCR5, has gotten recent attention after studies showed that defects in its structure (caused by genetic mutations) cause the progression of AIDS to be prevented or slowed. Scientists hope that this discovery will lead to the development of drugs that trigger an artificial mutation of the CCR5 gene or target the CCR5 receptor.

Once HIV has entered the cell, it can replicate intracellularly and kill the cell in ways that are still not completely understood. In addition to killing some lymphocytes directly, the AIDS virus disrupts the functioning of the remaining CD4 cells. Because the immune system cells are destroyed, many different types of infections and cancers that take advantage of a person's weakened immune system (opportunistic) can develop.

Autoimmunity is a condition in which the body's immune system produces antibodies that work against its own cells. Antibodies are specific proteins produced in response to exposure to a specific, usually foreign, protein or particle called an antigen. In this case, the body produces antibodies that bind to blood platelets that are necessary for proper blood clotting and tissue repair. Once bound, the antibodies mark the platelets for removal from the body, and they are filtered out by the spleen. Some AIDS patients develop a disorder, called immune-related thrombocytopenia purpura (ITP), in which the number of blood platelets drops to abnormally low levels.

Researchers do not know precisely how HIV attacks the nervous system since the virus can cause damage without infecting nerve cells directly. One theory is that, once infected with HIV, one type of

KEY TERMS

Acute retroviral syndrome A group of symptoms resembling mononucleosis that often are the first sign of HIV infection in 50-70% of all patients and 45-90% of women.

AIDS dementia complex A type of brain dysfunction caused by HIV infection that causes difficulty thinking, confusion, and loss of muscular coordination.

Antibody A specific protein produced by the immune system in response to a specific foreign protein or particle called an antigen.

Antigen Any substance that stimulates the body to produce antibody.

Autoimmunity A condition in which the body's immune system produces antibodies in response to its own tissues or blood components instead of foreign particles or microorganisms.

CCR5 A chemokine receptor; defects in its structure caused by genetic mutation cause the progression of AIDS to be prevented or slowed.

CD4 A type of protein molecule in human blood, sometimes called the T4 antigen, that is present on the surface of 65% of immune cells. The HIV virus infects cells with CD4 surface proteins, and as a result, depletes the number of T cells, B cells, natural killer cells, and monocytes in the patient's blood. Most of the damage to an AIDS patient's immune system is done by the virus' destruction of CD4+ lymphocytes.

Chemokine receptor A receptor on the surface of some types of immune cells that helps to mediate entry of HIV into the cell.

Hairy leukoplakia of the tongue A white area of diseased tissue on the tongue that may be flat or slightly raised. It is caused by the Epstein-Barr virus and is an important diagnostic sign of AIDS.

Hemophilia Any of several hereditary blood coagulation disorders occurring almost exclusively in males. Because blood does not clot properly, even minor injuries can cause significant blood loss that may require a blood transfusion, with its associated minor risk of infection.

Human immunodeficiency virus (HIV) A transmissible retrovirus that causes AIDS in humans. Two forms of HIV are now recognized: HIV-1, which causes most cases of AIDS in Europe, North and South America, and most parts of Africa; and HIV-2, which is chiefly found in West African patients. HIV-2, discovered in 1986, appears to be less virulent than HIV-1 and may also have a longer latency period.

Immunodeficient A condition in which the body's immune response is damaged, weakened, or is not functioning properly.

Kaposi's sarcoma A cancer of the connective tissue that produces painless purplish red (in people with light skin) or brown (in people with dark skin) blotches on the skin. It is a major diagnostic marker of AIDS.

Latent period Also called incubation period, the time between infection with a disease-causing agent and the development of disease.

Lymphocyte A type of white blood cell that is important in the formation of antibodies and that can be used to monitor the health of AIDS patients.

Lymphoma A cancerous tumor in the lymphatic system that is associated with a poor prognosis in AIDS patients.

Macrophage A large white blood cell, found primarily in the bloodstream and connective tissue, that helps the body fight off infections by ingesting the disease-causing organism. HIV can infect and kill macrophages.

Monocyte A large white blood cell that is formed in the bone marrow and spleen. About 4% of the white blood cells in normal adults are monocytes.

Mycobacterium avium (MAC) infection A type of opportunistic infection that occurs in about 40% of AIDS patients and is regarded as an AIDS-defining disease.

Non-nucleoside reverse transcriptase inhibitors The newest class of antiretroviral drugs that work by inhibiting the reverse transcriptase enzyme necessary for HIV replication.

Nucleoside analogues The first group of effective anti-retroviral medications. They work by interfering with the AIDS virus' synthesis of DNA.

Opportunistic infection An infection by organisms that usually don't cause infection in people whose immune systems are working normally.

Persistent generalized lymphadenopathy (PGL) A condition in which HIV continues to produce chronic painless swellings in the lymph nodes during the latency period.

Pneumocystis carinii pneumonia (PCP) An opportunistic infection caused by a fungus that is a major cause of death in patients with late-stage AIDS.

Progressive multifocal leukoencephalopathy (PML) A disease caused by a virus that destroys white matter in localized areas of the brain. It is regarded as an AIDS-defining illness.

Protease inhibitors The second major category of drug used to treat AIDS that works by suppressing the replication of the HIV virus.

Protozoan A single-celled, usually microscopic organism that is eukaryotic and, therefore, different from bacteria (prokaryotic).

Retrovirus A virus that contains a unique enzyme called reverse transcriptase that allows it to replicate within new host cells.

T cells Lymphocytes that originate in the thymus gland. T cells regulate the immune system's response to infections, including HIV. CD4 lymphocytes are a subset of T lymphocytes.

Thrush A yeast infection of the mouth characterized by white patches on the inside of the mouth and cheeks.

Viremia The measurable presence of virus in the bloodstream that is a characteristic of acute retroviral syndrome.

Wasting syndrome A progressive loss of weight and muscle tissue caused by the AIDS virus.

immune system cell, called a macrophage, begins to release a toxin that harms the nervous system.

The course of AIDS generally progresses through three stages, although not all patients will follow this progression precisely:

Acute retroviral syndrome

Acute retroviral syndrome is a term used to describe a group of symptoms that can resemble mononucleosis and that may be the first sign of HIV infection in 50-70% of all patients and 45-90% of women. Most patients are not recognized as infected during this phase and may not seek medical attention. The symptoms may include fever, fatigue, muscle aches, loss of appetite, digestive disturbances, weight loss, skin rashes, headache, and chronically swollen lymph nodes (lymphadenopathy). Approximately 25-33% of patients will experience a form of meningitis during this phase in which the membranes that cover the brain and spinal cord become inflamed. Acute retroviral syndrome develops between one and six weeks after infection and lasts for two to three weeks. Blood tests during this period will indicate the presence of virus (viremia) and the appearance of the viral p24 antigen in the blood.

Latency period

After the HIV virus enters a patient's lymph nodes during the acute retroviral syndrome stage, the disease becomes latent for as many as 10 years or more before symptoms of advanced disease develop. During latency, the virus continues to replicate in the lymph nodes, where it may cause one or more of the following conditions:

PERSISTENT GENERALIZED LYMPHADENOPATHY (PGL). Persistent generalized lymphadenopathy, or PGL, is a condition in which HIV continues to produce chronic painless swellings in the lymph nodes during the latency period. The lymph nodes that are most frequently affected by PGL are those in the areas of the neck, jaw, groin, and armpits. PGL affects between 50-70% of patients during latency.

CONSTITUTIONAL SYMPTOMS. Many patients will develop low-grade fevers, chronic fatigue, and general weakness. HIV may also cause a combination of food malabsorption, loss of appetite, and increased metabolism that contribute to the so-called AIDS wasting or wasting syndrome.

OTHER ORGAN SYSTEMS. At any time during the course of HIV infection, patients may suffer from a yeast infection in the mouth called thrush, open sores or ulcers, or other infections of the mouth; diarrhea and other gastrointestinal symptoms that cause malnutrition and weight loss; diseases of the lungs and kidneys; and degeneration of the nerve fibers in the arms and legs. HIV infection of the nervous system leads to general loss of strength, loss of reflexes, and feelings of numbness or burning sensations in the feet or lower legs.

Late-stage disease (AIDS)

AIDS is usually marked by a very low number of CD4+ lymphocytes, followed by a rise in the frequency of opportunistic infections and cancers. Doctors monitor the number and proportion of CD4+ lymphocytes in the patient's blood in order to assess the progression of the disease and the effectiveness of different medications. About 10% of infected individuals never progress to this overt stage of the disease and are referred to as nonprogressors.

OPPORTUNISTIC INFECTIONS. Once the patient's CD4+ lymphocyte count falls below 200 cells/mm3, he or she is at risk for a variety of opportunistic infections. The infectious organisms may include the following:

  • Fungi. The most common fungal disease associated with AIDS is Pneumocystis carinii pneumonia (PCP). PCP is the immediate cause of death in 15-20% of AIDS patients. It is an important measure of a patient's prognosis. Other fungal infections include a yeast infection of the mouth (candidiasis or thrush) and cryptococcal meningitis.
  • Protozoa. Toxoplasmosis is a common opportunistic infection in AIDS patients that is caused by a protozoan. Other diseases in this category include isoporiasis and cryptosporidiosis.
  • Mycobacteria. AIDS patients may develop tuberculosis or MAC infections. MAC infections are caused by Mycobacterium avium-intracellulare, and occur in about 40% of AIDS patients. It is rare until CD4+ counts falls below 50 cells/mm3.
  • Bacteria. AIDS patients are likely to develop bacterial infections of the skin and digestive tract.
  • Viruses. AIDS patients are highly vulnerable to cytomegalovirus (CMV), herpes simplex virus (HSV), varicella zoster virus (VZV), and Epstein-Barr virus (EBV) infections. Another virus, JC virus, causes progressive destruction of brain tissue in the brain stem, cerebrum, and cerebellum (multifocal leukoencephalopathy or PML), which is regarded as an AIDS-defining illness by the Centers for Disease Control and Prevention.

AIDS DEMENTIA COMPLEX AND NEUROLOGIC COMPLICATIONS. AIDS dementia complex is usually a late complication of the disease. It is unclear whether it is caused by the direct effects of the virus on the brain or by intermediate causes. AIDS dementia complex is marked by loss of reasoning ability, loss of memory, inability to concentrate, apathy and loss of initiative, and unsteadiness or weakness in walking. Some patients also develop seizures. There are no specific treatments for AIDS dementia complex.

MUSCULOSKELETAL COMPLICATIONS. Patients in late-stage AIDS may develop inflammations of the muscles, particularly in the hip area, and may have arthritis-like pains in the joints.

ORAL SYMPTOMS. In addition to thrush and painful ulcers in the mouth, patients may develop a condition called hairy leukoplakia of the tongue. This condition is also regarded by the CDC as an indicator of AIDS. Hairy leukoplakia is a white area of diseased tissue on the tongue that may be flat or slightly raised. It is caused by the Epstein-Barr virus.

AIDS-RELATED CANCERS. Patients with late-stage AIDS may develop Kaposi's sarcoma (KS), a skin tumor that primarily affects homosexual men. KS is the most common AIDS-related malignancy. It is characterized by reddish-purple blotches or patches (brownish in African-Americans) on the skin or in the mouth. About 40% of patients with KS develop symptoms in the digestive tract or lungs. KS may be caused by a herpes virus-like sexually transmitted disease agent rather than HIV.

The second most common form of cancer in AIDS patients is a tumor of the lymphatic system (lymphoma). AIDS-related lymphomas often affect the central nervous system and develop very aggressively.

Invasive cancer of the cervix (related to certain types of human papilloma virus [HPV]) is an important diagnostic marker of AIDS in women.

While incidence of AIDS-defining cancers such as Kaposi's sarcoma and cervical cancer have decreased since increase use of antiretroviral therapy, other cancers has increased in AIDS patients. People with HIV has shown higher incidence of lung cancer, head and neck cancers, Hodgkin's lymphoma, melanoma, and anorectal cancer from 1992 to 2002.

Diagnosis

Because HIV infection produces such a wide range of symptoms, the CDC has drawn up a list of 34 conditions regarded as defining AIDS. The physician will use the CDC list to decide whether the patient falls into one of these three groups:

  • definitive diagnoses with or without laboratory evidence of HIV infection
  • definitive diagnoses with laboratory evidence of HIV infection
  • presumptive diagnoses with laboratory evidence of HIV infection.

Physical findings

Almost all the symptoms of AIDS can occur with other diseases. The general physical examination may range from normal findings to symptoms that are closely associated with AIDS. These symptoms are hairy leukoplakia of the tongue and Kaposi's sarcoma. When the doctor examines the patient, he or she will look for the overall pattern of symptoms rather than any one finding.

Laboratory tests for HIV infection

BLOOD TESTS (SEROLOGY). The first blood test for AIDS was developed in 1985. At present, patients who are being tested for HIV infection are usually given an enzyme-linked immunosorbent assay (ELISA) test for the presence of HIV antibody in their blood. Positive ELISA results are then tested with a Western blot or immunofluorescence (IFA) assay for confirmation. The combination of the ELISA and Western blot tests is more than 99.9% accurate in detecting HIV infection within four to eight weeks following exposure. The polymerase chain reaction (PCR) test can be used to detect the presence of viral nucleic acids in the very small number of HIV patients who have false-negative results on the ELISA and Western blot tests. These tests are also used to detect viruses and bacterium other than HIV and AIDS.

OTHER LABORATORY TESTS. In addition to diagnostic blood tests, there are other blood tests that are used to track the course of AIDS in patients that have already been diagnosed. These include blood counts, viral load tests, p24 antigen assays, and measurements of β2-microglobulin (β2M).

Doctors will use a wide variety of tests to diagnose the presence of opportunistic infections, cancers, or other disease conditions in AIDS patients. Tissue biopsies, samples of cerebrospinal fluid, and sophisticated imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography scans (CT) are used to diagnose AIDS-related cancers, some opportunistic infections, damage to the central nervous system, and wasting of the muscles. Urine and stool samples are used to diagnose infections caused by parasites. AIDS patients are also given blood tests for syphilis and other sexually transmitted diseases.

Diagnosis in children

Diagnostic blood testing in children older than 18 months is similar to adult testing, with ELISA screening confirmed by Western blot. Younger infants can be diagnosed by direct culture of the HIV virus, PCR testing, and p24 antigen testing.

In terms of symptoms, children are less likely than adults to have an early acute syndrome. They are, however, likely to have delayed growth, a history of frequent illness, recurrent ear infections, a low blood cell count, failure to gain weight, and unexplained fevers. Children with AIDS are more likely to develop bacterial infections, inflammation of the lungs, and AIDS-related brain disorders than are HIV-positive adults.

Treatment

Treatment for AIDS covers four considerations:

TREATMENT OF OPPORTUNISTIC INFECTIONS AND MALIGNANCIES. Most AIDS patients require complex long-term treatment with medications for infectious diseases. This treatment is often complicated by the development of resistance in the disease organisms. AIDS-related malignancies in the central nervous system are usually treated with radiation therapy. Cancers elsewhere in the body are treated with chemotherapy.

PROPHYLACTIC TREATMENT FOR OPPORTUNISTIC INFECTIONS. Prophylactic treatment is treatment that is given to prevent disease. AIDS patients with a history of Pneumocystis pneumonia; with CD4+ counts below 200 cells/mm3 or 14% of lymphocytes; weight loss; or thrush should be given prophylactic medications. The three drugs given are trimethoprim-sulfamethoxazole, dapsone, or pentamidine in aerosol form.

ANTI-RETROVIRAL TREATMENT. In recent years researchers have developed drugs that suppress HIV replication, as distinct from treating its effects on the body. These drugs fall into four classes:

  • Nucleotide analogues. These drugs work by interfering with the action of HIV reverse transcriptase inside infected cells, thus ending the virus' replication process. These drugs include zidovudine (sometimes called azidothymidine or AZT), didanosine (ddI), zalcitabine (ddC), stavudine (d4T), lamivudine (3TC), and abacavir (ABC).
  • Protease inhibitors. Protease inhibitors can be effective against HIV strains that have developed resistance to nucleoside analogues, and are often used in combination with them. These compounds include saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, and lopinavir..
  • Non-nucleoside reverse transcriptase inhibitors. This is a new class of antiretroviral agents. Three are available, nevirapine, which was approved first, delavirdine and efavirin.
  • Fusion inhibitors, the newest class of antiretrovirals. They block specific proteins on the surface of the virus or the CD4 cell. These proteins help the virus gain entry into the cell.The only FDA approved fusion inhibitor as of spring 2004 was enfuvirtide.

Treatment guidelines for these agents are in constant change as new medications are developed and introduced. Two principles currently guide doctors in working out drug regimens for AIDS patients: using combinations of drugs rather than one medication alone; and basing treatment decisions on the results of the patient's viral load tests.

STIMULATION OF BLOOD CELL PRODUCTION. Because many patients with AIDS suffer from abnormally low levels of both red and white blood cells, they may be given medications to stimulate blood cell production. Epoetin alfa (erythropoietin) may be given to anemic patients. Patients with low white blood cell counts may be given filgrastim or sargramostim.

Treatment in women

Treatment of pregnant women with HIV is particularly important in that anti-retroviral therapy has been shown to reduce transmission to the infant by 65%.

Alternative treatment

Alternative treatments for AIDS can be grouped into two categories: those intended to help the immune system and those aimed at pain control. Treatments that may enhance the function of the immune system include Chinese herbal medicine and western herbal medicine, macrobiotic and other special diets, guided imagery and creative visualization, homeopathy, and vitamin therapy. Pain control therapies include hydrotherapy, reiki, acupuncture, meditation, chiropractic treatments, and therapeutic massage. Alternative therapies can also be used to help with side effects of the medications used in the treatment of AIDS.

Prognosis

At the present time, there is no cure for AIDS.

Treatment stresses aggressive combination drug therapy for those patients with access to the expensive medications and who tolerate them adequately. The use of these multi-drug therapies has significantly reduced the numbers of deaths, in this country, resulting from AIDS. The data is still inconclusive, but the potential exists to possibly prolong life indefinitely using these and other drug therapies to boost the immune system, keep the virus from replicating, and ward off opportunistic infections and malignancies.

Prognosis after the latency period depends on the patient's specific symptoms and the organ systems affected by the disease. Patients with AIDS-related lymphomas of the central nervous system die within two to three months of diagnosis; those with systemic lymphomas may survive for eight to ten months.

Prevention

As of 2005, there was no vaccine effective against AIDS. Several vaccines are currently being investigated, however, both to prevent initial HIV infection and as a therapeutic treatment to prevent HIV from progressing to full-blown AIDS.

In the meantime, there are many things that can be done to prevent the spread of AIDS:

  • Being monogamous and practice safe sex. Individuals must be instructed in the proper use of condoms and urged to practice safe sex. Besides avoiding the risk of HIV infection, condoms are successful in preventing other sexually transmitted diseases and unwanted pregnancies. Before engaging in a sexual relationship with someone, getting tested for HIV infection is recommended.
  • Avoiding needle sharing among intravenous drug users.
  • Although blood and blood products are carefully monitored, those individuals who are planning to undergo major surgery may wish to donate blood ahead of time to prevent a risk of infection from a blood transfusion.
  • Healthcare professionals must take all necessary precautions by wearing gloves and masks when handling body fluids and preventing needle-stick injuries.
  • If someone suspects HIV infection, he or she should be tested for HIV. If treated aggressively and early, the development of AIDS may be postponed indefinitely. If HIV infection is confirmed, it is also vital to let sexual partners know so that they can be tested and, if necessary, receive medical attention.

Resources

PERIODICALS

Boschert, Sherry. "Some Ca Increasing in Post-HAART Era." Clinical Psychiatry News June 2004: 75.

Godwin, Catherine. "WhatÆs New in the Fight Against AIDS." RN April 2004: 46-54.

ORGANIZATIONS

Gay Men's Health Crisis, Inc., 129 West 20th Street, New York, NY 10011-0022. (212) 807-6655.

National AIDS Hot Line. (800) 342-AIDS (English). (800) 344-SIDA (Spanish). (800) AIDS-TTY (hearing-impaired).

OTHER

"FDA Approved Drugs for HIV Infection and AIDS-RelatedConditions." HIV/AIDS Treatment Information Service website. January 2001. http://hivatis.org.

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ACQUIRED IMMUNE DEFICIENCY SYNDROME

A disease caused by the human immunodeficiency virus (HIV) that produces disorders and infections that can lead to death.

Acquired immune deficiency syndrome (AIDS), a fatal disease that attacks the body's immune system making it unable to resist infection, is caused by the human immunodeficiency

What Causes AIDS—and What Does Not?

Since the first case was identified in 1981, acquired immune deficiency syndrome (AIDS) has grown into an epidemic that has taken approximately 500,000 lives in the United States alone. The Joint united nations Programme on HIV/AIDS estimates that at the end of 2002 there were 42 million people living with HIV/AIDS worldwide. During 2002, AIDS caused the deaths of an estimated 3.1 million people. At this time, women were increasingly affected by AIDS; it was estimated that women comprised approximately 50 percent or 19.2 million of the 38.6 million adults living with HIV or AIDS worldwide. No cure has been found, although existing treatment employing multiple drugs has made some gains in prolonging life and reducing pain. Despite the limits of medical science, however, much is known about the disease. It is caused by the human immunodeficiency virus (HIV). Transmitted by bodily fluids from person to person, HIV invades certain key blood cells that are needed to fight off infections. HIV replicates, spreads, and destroys these host cells. When the body's immune system becomes deficient, the person becomes AIDS-symptomatic, which means the person develops infections that the body can no longer ward off. Ultimately, a person with AIDS dies from diseases caused by other infections. The leading killer is a form of pneumonia.

Most of the fear surrounding AIDS has to do with its most common form of transmission: sexual behavior. The virus can be passed through any behavior that involves the exchange of blood, semen, or vaginal secretions. Anal intercourse is the highest-risk activity, but oral or vaginal intercourse is dangerous too. Thus, federal health authorities recommend using a condom—yet they caution that condoms are not 100 percent effective; condoms can leak, and they can break. Highly accurate HIV testing is widely available, and often advisable, since infected people can feel perfectly healthy. Although the virus can be contracted immediately upon exposure to it, symptoms of full-blown AIDS may take up to ten years to appear.

In addition to sexual behavior, only a few other means of HIV transmission exist. Sharing unsterilized needles used in drug injections is one way, owing to the exchange of blood on the needle, and thus intravenous drug users are an extremely high-risk group. Several cities have experimented with programs that offer free, clean needles. These programs have seen up to a 75 percent reduction in new HIV cases. Receipt of donations of blood, semen, organs, and other human tissue can also transmit HIV, although here, at least, screening methods have proved largely successful. Childbirth and breast feeding are also avenues of transmission, and thus children of HIV-positive mothers may be at risk.

The medical facts about HIV and AIDS are especially relevant to the law. Unless exposed in one of a few very specific ways, most people have nothing to fear. Casual contact with people who are infected is safe. Current medical knowledge is quite strong on this point: no one is known to have caught the virus by sitting next to, shaking the hand of, or breathing the same air as an infected person. For this reason, U.S. law has moved to protect the civil rights of HIV-positive and AIDS-symptomatic persons. Section 504 of the Rehabilitation Act of 1973, 29 U.S.C. § 794 (1994) prohibits discrimination against otherwise qualified disabled individuals, including individuals with a contagious disease or an infection such as HIV or AIDS. The AIDS quilt, on display in Washington, D.C., has become a well-known symbol of support for victims of AIDS and their families. Families and supporters of victims of AIDS create a panel to commemorate that person's life and that panel is joined with others from around the country to create the quilt.

further readings

Barnett, Tony, and Alan Whiteside. 2003. AIDS in the Twenty-First Century. New York: Palgrave Macmillan.

Farmer, Paul. 2003. Pathologies of Power: Health, Human Rights, and the New War on the Poor. Berkeley: Univ. of California Press.

cross-references

Discrimination.

virus (HIV), which is communicable in some bodily fluids and transmitted primarily through sexual behavior and intravenous drug use.

Reading, Writing, and Aids

Teaching young people about AIDS is an enormously popular idea. Since the late 1980s, Gallup Polls have revealed that over 90 percent of respondents think public schools should do so. Agreement ends there, however. In the 1990s, more angry debate focused on AIDS education than on any issue facing schools since court-ordered busing in the 1970s. The core question of the debate is simple: What is the best way to equip students to protect themselves from this fatal disease? The answers may be miles apart. For one side, "equipping" means advocating the only sure means of protection, sexual and drug abstinence. For the other, it means supporting abstinence along with knowledge of sexual practices, the use of clean drug needles, and the use of prophylactics (condoms), which are distributed in some schools. Between these positions lie a great many issues of disagreement that have bitterly divided school districts, provoked lawsuits, and cost high-ranking Washington, D.C., officials their jobs.

Sex is an old battleground in public education. Liberals and conservatives argued over it in the decade following the sexual revolution of the 1960s, initially over whether sexual issues should be discussed in schools. After all, earlier generations who went to public schools learned mainly about reproductive organs. As new classes began appearing in the late 1970s, children learned about the sexual choices people make. If liberals appeared to win the "sex ed." debate, growing social problems helped: rises in teen pregnancies and sexually transmitted diseases secured a place for more explicit school health classes. The much greater threat of AIDS pushed state legislatures into action. By the mid-1990s, AIDS prevention classes had been mandated in at least 34 states and recommended in 14. But the appearance of even more explicit teaching has reinvigorated the sex ed. debate.

Supporters of a comprehensive approach say AIDS demands frankness. Originating in comprehensive sex ed. theory, their ideas also came from pacesetting health authorities such as former surgeon general c. everett koop. Arguing in the mid-1980s that AIDS classes should be specific and detailed and taught as early as kindergarten, Koop countered conservative arguments by saying, "Those who say 'I don't want my child sexually educated' are hiding their heads in the sand." This position holds that educators are obligated to teach kids everything that can stop the spread of the disease. "What is the moral responsibility?" Jerald Newberry, a health coordinator of Virginia schools, asked the Washington Times in 1992. "I think it's gigantic." Abstinence is a part of this approach, but expecting teens to refrain from having sex was considered by many to be unrealistic given some studies that show that nearly three out of four high school students have had sex before graduation. Thus, the comprehensive curriculum might well include explaining the proper use of condoms, discussing homosexual practices, describing the sterilization of drug needles, and so on.

Abstinence-only adherents think being less frank is being more responsible. They view sexuality as a moral issue properly left for parents to discuss with their children and one that lies beyond the responsibilities of schools. The conservative columnist Cal Thomas spoke for this viewpoint when he argued that parents "have lost a significant right to rear their children according to their own moral standards." Other objections come from religious conservatives who oppose any neutral or positive discussion of homosexuality. Koop, for example, was blasted for allegedly "sponsoring homosexually oriented curricula" and "teaching buggery in the 3rd grade." In addition to voicing moral objections, critics say comprehensive sex ed. is generally a failure because it encourages a false sense of security among teens that leads to experimentation with sex or drugs. "We have given children more information presumably because we think it will change their behavior, and yet the behavior has gotten worse, not better," said Gary Bauer, president of the Family Research Council.

Each side accuses the other of deepening the crisis. Comprehensive approach supporters think abstinence-only backers are moral censors, indifferent to pragmatic solutions. The liberal People for the American Way attacked "a growing wave of censorship ravaging sexuality education" that promotes only "narrow" curricula. It mocked such abstinence-only programs as Teen Aid and Sex Respect, both of which have brought threats of legal action from the american civil liberties union and Planned Parenthood. The conservative American Enterprise Institute asserted that liberal programs only prod students toward bad choices: "There has been a transition from protection to preparation." Neither side can agree on any data, other than to point out that the problems of AIDS and teen sexuality have appeared to worsen.

Nowhere are the two sides more split than on the issue of condoms. Schools in at least 23 cities sought to distribute condoms during the mid-to late-1990s. The assumption was that since students will have sex anyway—despite warnings not to—they had better be protected. Conservatives see this position as a cop-out in two ways: it sells values short and it undermines parental authority. In 1992, in Washington, D.C., critics erupted over a decision by the Public Health Commission to hand out condoms in junior and senior high schools without parental consent. William Brown, president of the D.C. Congress of Parents and Teachers, complained: "We are looking to build and reinforce and establish family values where they have been lost, and here we have an agency of our government that totally ignores those things we are working for." Dr. Mary Ellen Bradshaw, the commission's chief, replied: "Our whole focus is to save the lives of these children, stressing abstinence as the only sure way to avoid [AIDS] and making condoms available only after intensive education." In other cities, upset parents simply sued. By 1992, class action lawsuits had been brought against school districts in New York City, Seattle, and Falmouth, Massachusetts, arguing that condom distribution violated parents' right to privacy.

AIDS education in schools is not merely a local issue. While most decisions are made by states and school boards the federal government plays two important roles. First, it funds AIDS prevention programs: abstinence-based programs receive funding under the Adolescent Family Life Act of 1981, and programs that promote contraceptive use among teenagers are supported through the Family Planning Act of 1970. How these funds are spent is a matter of local control, but conservatives have sought to put limits on program content. During the early 1990s, Senator jesse helms (R-NC) twice tried to ban funding for programs that were perceived to promote homosexuality or that did not continuously teach abstinence as the only effective protection against AIDS. In response, one federal agency, the Center for Disease Control, adopted regulations that prohibited the use of funds on any materials that are found offensive by some members of communities.

The second role of the federal government is largely symbolic but no less controversial. It is to guide school efforts through advice, sponsorship, and public speeches, and primarily involves the offices of the surgeon general and of the federal AIDS policy coordinator. Koop, who was a Reagan appointee, roused a fair degree of controversy, yet it was nothing compared to the upheaval that greeted statements by appointees of the Clinton administration. AIDS policy czar Kristine Gebbie and surgeon general M. Joycelyn Elders were forced from their posts after making statements that conservatives found appalling—Gebbie promoting attitudes toward pleasurable sex and Elders indicating a willingness to have schools talk about masturbation. Thereafter, the administration frequently stressed abstinence as its top priority for school AIDS programs.

Problems surrounding AIDS education are unlikely to go away. Communities frequently disagree on sex education itself, and compromise is often difficult on such a divisive issue of values. As the experience of the Clinton administration suggested, Washington, D.C., could easily exacerbate an already contentious area, with policy coordinators becoming lightning rods for criticism. On the matter of what to say to kids about AIDS, poll data have been misleading. U.S. citizens are of three minds: say a lot, say a little, and do not say what the other side thinks.

further readings

Kelly, Pat. 1998. Coping When Your Friend Is HIV-Positive. New York: Rosen Publishing Group.

National Commission on Acquired Immune Deficiency Syndrome. 1993. National Commission on AIDS: An Expanding Tragedy: The Final Report of the National Commission on AIDS. Washington, D.C.: National Commission on Acquired Immune Deficiency Syndrome.

World Health Organization. 1989. Legislative Responses to AIDS. Boston: Martinus Nijhoff Publishers.

cross-references

Civil Rights Acts; Schools and School Districts.

The United States struggled to cope with AIDS from the early 1980s until the late 1990s, when new drug therapies started to extend the length and quality of life for many people with AIDS. Since the beginning, AIDS and its resulting epidemic in the United States have raised a great number of legal issues, which are made all the more difficult by the nature of the disease. AIDS is a unique killer, but some of its aspects are not: epidemics have been seen before; other sexually transmitted diseases have been fatal. AIDS is different because it was discovered in—and in the United States still predominantly afflicts—unpopular social groups: gay men and drug users. This fact has had a strong impact on the shaping of AIDS law. Law is often shaped by politics, and AIDS is a highly politicized disease. The challenge in facing an epidemic that endangers everyone is complicated by the stigma attached to the people most likely to be killed by it.

Epidemics have no single answer beyond a cure. Since no cure for AIDS existed as of the early 2000s, the law continued to grapple with a vast number of problems. The federal government has addressed AIDS in two broad ways: by spending money on research and treatment of the disease and by prohibiting unfairness to people with HIV or AIDS. It has funded medical treatment, research, and public education, and it has passed laws prohibiting discrimination against people who are HIV-positive or who have developed AIDS. States and local municipalities have joined in these efforts, sometimes with federal help. In addition, states have criminalized the act of knowingly transmitting the virus through sexual behavior or blood donation. The courts, of course, are the decision makers in AIDS law. They have heard a number of cases in areas that range from employment to education and from crimes to torts. Although a body of case law has developed, it remains relatively new with respect to most issues and controversial in all.

AIDS and the Federal Government

Political attitudes toward AIDS have gone through dramatically different phases. In the early 1980s, it was dubbed the gay disease and as such was easy for lawmakers to ignore. No one hurried to fund research into a disease that seemed to be killing only members of a historically unpopular group. When it was not being ignored, some groups dismissed AIDS as a problem that homosexuals deserved, perhaps brought on them by divine intervention. Discriminatory action matched this talk as gay men lost jobs, housing, and medical care. AIDS activists complained bitterly about the failure of

most U.S. citizens to be concerned. Public opinion only began to shift in the late 1980s, largely through awareness of highly publicized cases. As soon as AIDS had a familiar or more mainstream face, it became harder to ignore; when it became clear that heterosexuals were also contracting the disease, the epidemic acquired higher priority.

By the late 1980s, much of the harshness in public debate had diminished. Both liberals and conservatives lined up to support legislative solutions. President ronald reagan left office, recommending increases in federal funding for medical research on AIDS. Already the amount spent in this area had risen from $61 million in 1984 to nearly $1.3 billion in 1988. President george h.w. bush took a more active approach, and in 1990 signed two new bills into law. One was the Ryan White Comprehensive AIDS Resources Emergency (CARE) Act (Pub. L. No. 101-381, 104 Stat. 576), which provides much-needed money for states to spend on treatment. The other was the ground-breaking Americans with Disabilities Act (ADA) (42 U.S.C.A. §§ 12112–12117), which has proved to be the most effective weapon against the discrimination that individuals with the disease routinely suffer. Bush also hurried approval by the food and drug administration for AIDS-related drugs. Though he supported Americans with the disease, Bush agreed to a controversial ban by Congress on travel and immigration to the United States for people with HIV.

Like his predecessors, President bill clinton called for fighting the disease, rather than the people afflicted with it. In 1993, he appointed the first federal AIDS policy coordinator. He fully funded the Ryan White Care Act, increasing government support by 83 percent, to $633 million, and also increased funding for AIDS research, prevention, and treatment by 30 percent. These measures met most of his campaign promises on AIDS. He reneged on one: despite vowing to lift the ban on HIV-positive aliens, he signed legislation continuing it. In addition, he met a major obstacle on another proposal: Congress failed to pass his health care reform package, which would have provided health coverage to all U.S. citizens with HIV, delivered drug treatment against AIDS on demand to intravenous drug users, and prohibited health plans from providing lower coverage for AIDS than for other life-threatening diseases.

AIDS and Public Life

Having HIV is not a sentence to remove oneself from society. It does not limit a person's physical or mental abilities. Only later, when symptoms develop—as long as ten years from the time of infection—does the disease become increasingly debilitating. In any event, people who are HIV-positive and AIDS-symptomatic are fully able to work, play, and participate in daily life. Moreover, their rights to do so are the same as anyone else's. The chief barrier to a productive life often comes less from HIV and AIDS than from the fear, suspicion, and open hostility of others. Because HIV cannot be transmitted through casual contact, U.S. law has moved to defend the civil rights of those individuals with the disease.

AIDS in the Workplace The workplace is a common battleground. Many people with AIDS have lost their jobs, been denied promotions, or been reassigned to work duties that remove them from public contact. During the 1980s, this discrimination was fought through lawsuits based on older laws designed to protect the disabled. Plaintiffs primarily used the Rehabilitation Act of 1973 (29 U.S.C.A. § 701 et seq.), the earliest law of this type. But the Rehabilitation Act has a limited scope: it applies only to federally funded workplaces and institutions; it says nothing about those that do not receive government money. Thus, for example, the law was helpful to a California public school teacher with AIDS who sued for the right to resume teaching classes (Chalk v. United States District Court, 840 F.2d 701 [9th Cir. 1988]), but it would be of no use to a worker in a private business.

With passage of the ADA in 1990, Congress gave broad protection to people with AIDS who work in the private sector. In general, the ADA is designed to increase access for disabled persons, and it also forbids discrimination in hiring or promotion in companies with fifteen or more employees. Specifically, employers may not discriminate if the person in question is otherwise qualified for the job. Moreover, they cannot use tests to screen out disabled persons, and they must provide reasonable accommodation for disabled workers. The ADA, which took effect in 1992, quickly emerged as the primary means for bringing AIDS-related discrimination lawsuits. From 1992 to 1993, more than 330 complaints were filed with the U.S. equal employment opportunity commission (EEOC), which investigates charges before they can be filed in court. Given the lag time needed for EEOC investigations, those cases started appearing before federal courts in 1994 and 1995.

AIDS and Health Care Closely related to work is the issue of health care. In some cases, the two overlap: health insurance, social security, and disability benefits for people with AIDS were often hard to obtain during the 1980s. Insurance was particularly difficult because employers feared rising costs, and insurance companies did not want to pay claims. To avoid the costs of AIDS, insurance companies used two traditional industry techniques: they attempted to exclude AIDS coverage from general policies, and they placed caps (limits on benefits payments) on AIDS-related coverage. State regulations largely determine whether these actions were permissible. In New York, for example, companies that sell general health insurance policies are forbidden to exclude coverage for particular diseases. Caps have hurt AIDS patients because their treatment can be as expensive as that for cancer or other life-threatening illnesses. Insurance benefits can be quickly exhausted—in fact, AIDS usually bankrupts people who have the disease. The problem is compounded when employers serve as their own health insurers. In McGann v. H&H Music Co., 946, F.2d 401 (5th Cir. [1991]), a federal court ruled that such employers could legally change their policies to reduce coverage for workers who develop expensive illnesses such as AIDS.

In January 1995, the settlement in a lawsuit brought by a Philadelphia construction worker with AIDS illustrated that the ADA could be used to fight caps on coverage. In 1992, the joint union-management fund for the Laborers' District Council placed a $10,000 limit on AIDS benefits, in stark contrast to the $100,000 allowed for other catastrophic illnesses. At that time, the fund said the cap on AIDS benefits was designed to curb all health costs. In 1993, the EEOC ruled that the fund violated the ADA, and, backed by the AIDS Law Project of Philadelphia, the worker sued. Rather than fight an expensive lawsuit, the insurance fund settled: under the agreement, it extended coverage for all catastrophic illnesses to $100,000. Hailing the settlement as a major blow against widespread discrimination in insurance coverage, the law project's executive director, Nan Feyler, told thePhiladelphia Inquirer, "You can't single out someone based on a stereotype."

In other respects, health care is a distinct area of concern for AIDS patients and health professionals alike. Discrimination has often taken place. State and federal statutes, including the Rehabilitation Act, guarantee access to health care for AIDS patients, and courts have upheld that right. In the 1988 case of Doe v. Centinela Hospital, 57 U.S.L.W. 2034 (C.D. Cal.), for example, an HIV-infected person with no symptoms was excluded from a federally funded hospital residential program for drug and alcohol treatment because health care providers feared exposure to the virus. The case itself exposed the irrationality of such discrimination. Although its employees had feared HIV, the hospital argued in court that the lack of symptoms meant that the patient was not disabled and thus not protected by the Rehabilitation Act. A federal trial court in California rejected this argument, ruling that a refusal to grant services based solely on fear of contagion is discrimination under the Rehabilitation Act.

Other actions during the 1990s have relied upon the ADA. In 1994, the U.S. Justice Department reached a settlement in a lawsuit with the city of Philadelphia that ensures that city employees will treat patients with AIDS. The first settlement in a health care–related ADA suit, the case grew out of an incident in 1993: when an HIV-positive man collapsed on a Philadelphia street, emergency medical workers not only refused to touch him but told him to get on a stretcher by himself. The man sued. In settling the case, the city agreed to begin an extensive training program for its 900 emergency medical technicians and 1,400 firefighters. In addition, officials paid the man $10,000 in compensatory damages and apologized. The justice department viewed the suit as an important test of the ADA. Assistant Attorney General James Turner said the settlement would "send a clear message to all cities across the nation that we will not tolerate discrimination against persons with AIDS."

Health care professionals are not the only ones with concerns about HIV transmission. Patients may legitimately wonder if their doctors are infected. During the early 1990s, the medical and legal communities debated whether HIV-positive doctors have a duty to inform their patients of the illness. According to the Centers for Disease Control (CDC), the risk of HIV transmission from health care workers to patients is very small when recommended infection-control procedures are followed, yet this type of transmission has occurred. The first cases of patients contracting HIV during a medical procedure were reported in 1991: Dr. David J. Acer, a Florida dentist with AIDS, apparently transmitted HIV to five patients. One was Kimberly Bergalis, age twenty-three, who died as a result. Before her death, Bergalis brought a claim against the dentist's professional liability insurer, contending that it should have known that Acer had AIDS and effectively barred him from operating by refusing to issue him a malpractice insurance policy. Bergalis's claim was settled for $1 million. A second claim by Bergalis, against the insurance company that recommended Acer to her, was settled for an undisclosed amount.

Since the Bergalis case, many U.S. dentists, physicians, and surgeons with AIDS have begun disclosing their status to their patients. Faya v. Almaraz, 329 Md. 435, 620 A.2d 327 (Md. 1993), illustrates the consequences of not doing so. In Faya, the court held that an HIV-positive doctor has the legal duty to disclose this medical condition to patients and that a failure to inform can lead to a negligence action, even if the patients have not been infected by the virus. The doctor's patient did not contract HIV but did suffer emotionally from a fear of having done so. The unanimous decision held that patients can be compensated for their fears. Although this case dealt specifically with doctor-patient relationships, others have concerned a variety of relationships in which the fear of contracting AIDS can be enough for a plaintiff to recover damages.

Routine HIV-testing in healthcare facilities also raises legal issues. Most people who are HIV-positive want this information kept confidential. Facilities are free to use HIV testing to control the infection but in most states only with the patient's informed consent. Some states, such as Illinois, require written consent. The level of protection for medical records varies from state to state. California, for example, has broad protections; under its statutes, no one can be compelled to provide information that would identify anyone who is the subject of an HIV test. However, every state requires that AIDS cases be reported to the CDC, which tracks statistics on the spread of HIV. Whether the name of an HIV-infected person is reported to the CDC depends on state laws and regulations.

AIDS and Education Issues in the field of education include the rights of HIV-positive students to attend class and of HIV-positive teachers to teach, the confidentiality of HIV records, and how best to teach young people about AIDS. A few areas have been settled in court: for instance, the right of students to attend classes was of greater concern in the early years of the epidemic and later ceased to be a matter of dispute.

Certain students with AIDS may assert their right to public education under the Education for All Handicapped Children Act of 1975 (EAHCA), but the law is only relevant in cases involving special education programs. More commonly, students' rights are protected by the Rehabilitation Act. Perhaps the most important case in this area is Thomas v. Atascadero Unified School District, 662 F. Supp. 376 (C.D. Cal.1986), which illustrates how far such protections go. Thomas involved an elementary school student with AIDS who had bitten another youngster in a fight. Based on careful review of medical evidence, the U.S. District Court for the Central District of California concluded that biting was not proved to transmit AIDS, and it ordered the school district to readmit the girl. Similarly, schools that excluded teachers with AIDS have been successfully sued on the ground that those teachers pose no threat to their students or others and that their right to work is protected by the Rehabilitation Act, as in Chalk.

Confidentiality relating to HIV is not uniform in schools. Some school districts require rather broad dissemination of the information; others keep it strictly private. In the mid-1980s, the New York City Board of Education adopted a policy that nobody in any school would be told the identities of children with AIDS or HIV infection; only a few top administrators outside the school would be informed. The policy inspired a lawsuit brought by a local school district, which argued that the identity of a child was necessary for infection control (District 27 Community School Board v. Board of Education, 130 Misc. 2d 398, 502 N.Y.S.2d 325 [N.Y. Sup. Ct. 1986]). The trial court rejected the argument on the basis that numerous children with HIV infection might be attending school and instead noted that universal precautions in dealing with blood incidents at school would be more effective than the revelation of confidential information.

Schools play a major role in the effort to educate the public on AIDS. Several states have mandated AIDS prevention instruction in their schools. But the subject is controversial: it evokes personal, political, and moral reactions to sexuality. Responding to parental sensitivities, some states have authorized excused absences from such programs. The New York State Education

Department faced a storm of controversy over its policy of not allowing absences at parental discretion. Furthermore, at the local and the federal levels, some conservatives have opposed certain kinds of AIDS education. During the 1980s, those who often criticized liberal approaches to sex education argued that AIDS materials should not be explicit, encourage sexuality, promote the use of contraceptives, or favorably portray gays and lesbians. In Congress, lawmakers attached amendments to appropriations measures (bills that authorize the spending of federal tax dollars) that mandate that no federal funds may be used to "promote homosexuality." In response, the CDC adopted regulations that prohibit spending federal funds on AIDS education materials that might be found offensive by some members of certain communities. Despite the controversy, some communities have taken radical steps to halt the spread of AIDS. In 1991 and 1992, the school boards of New York City, San Francisco, Seattle, and Los Angeles voted to make condoms available to students in their public high school systems.

AIDS and Private Life

Although epidemics are public crises, they begin with individuals. The rights of people who have AIDS and those who do not are often in contention and seldom more so than in private life. It is no surprise that people with HIV continue having sex, nor is it a surprise that this behavior is, usually, legal. Unfortunately, some do so without knowing they have the virus. Even more unfortunately, others do so in full knowledge that they are HIV-positive but without informing their partners. This dangerous behavior has opened one area of AIDS law that affects individuals: the legal duty to warn a partner before engaging in behavior that can transmit the infection. A similar duty was recognized by courts long before AIDS ever appeared, with regard to other sexually transmitted diseases.

A failure to inform in AIDS cases has given rise to both civil and criminal lawsuits. One such case was brought by Mark Christian, the lover of actor Rock Hudson, against Hudson's estate. Christian won his suit on the ground that Hudson concealed his condition and continued their relationship, and the jury returned a multimillion-dollar verdict despite the fact that there was no evidence that Christian had been infected. Another case was brought in Oregon in 1991, when criminal charges were filed against Alberto Gonzalez for knowingly spreading HIV by having sex with his girlfriend. After Gonzalez pleaded no contest to third-degree assault (a felony) and to two charges of recklessly endangering others, he received an unusual sentence: the court ordered him to abstain from sex for five years and placed him under house arrest for six months. Although such convictions are increasingly common, courts have also recognized that not knowing one has HIV can be a valid defense. In C. A. U. v. R. L., 438 N.W.2d 441 (1989), for example, the Minnesota Court of Appeals affirmed a trial court's finding that the plaintiff could not recover damages from her former fiancé, who had unknowingly given her the virus.

State Legislation and the Courts To stem transmission of HIV, states have adopted several legal measures. Two states attempted to head off the virus at the pass: Illinois and Louisiana at one point required HIV blood testing as a prerequisite to getting a marriage license. Both states ultimately repealed these statutes because they were difficult to enforce; couples simply crossed state lines to be married in neighboring states. Several states have taken a less stringent approach, requiring only that applicants for a marriage license must be informed of the availability—and advisability—of HIV tests. More commonly, states criminalize sexual behavior that can spread AIDS. Michigan law makes it a felony for an HIV or AIDS-infected person to engage in sex without first informing a partner of the infection. Florida law provides for the prosecution of any HIV-positive person committing prostitution, and it permits rape victims to demand that their attackers undergo testing. Indiana imposes penalties on persons who recklessly or knowingly donate blood or semen with the knowledge that they are HIV-infected.

Older state laws have also been applied to AIDS. Several states have statutes that make it a criminal offense for a person with a contagious disease—including a sexually transmitted disease—to willfully or knowingly expose another person to it, and some have amended these laws specifically to include AIDS. In addition, in many states, it has long been a crime to participate in an act of sodomy. The argument that punishing sodomy can stem HIV transmission was made in a case involving a Missouri sodomy statute specifically limited to homosexual conduct. In State v. Walsh, 713 S.W.2d 508 (1986), the Missouri Supreme Court upheld the statute after finding that it was rationally related to the state's legitimate interest in protecting public health. Other AIDS-related laws have been invalidated in court challenges: for instance, in 1993, a U.S. district judge struck down a 1987 Utah statute that invalidated the marriages of people with AIDS, ruling that it violated the ADA and the Rehabilitation Act.

Sex is only one kind of behavior that has prompted criminal prosecution related to AIDS. Commonly, defendants in AIDS cases have been prosecuted for assault. In United States v. Moor, 846 F.2d 1163 (8th Cir., 1988), the Eighth Circuit upheld the conviction of an HIV-infected prisoner found guilty of assault with a deadly weapon—his teeth—for biting two prison guards during a struggle. Teeth were also on trial in Brock v. State, 555 So. 2d 285 (1989), but the Alabama Court of Criminal Appeals refused to regard them as a dangerous weapon. In State v. Haines, 545 N.E.2d 834 (2d Dist. 1989), the Indiana Court of Appeals affirmed a conviction of attempted murder against a man with AIDS who had slashed his wrists to commit suicide; when police officers and paramedics refused to let him die, he began to spit, bite, scratch, and throw blood.

Civil Litigation tort law has seen an explosion of AIDS-related suits. This area of law is used to discourage individuals from subjecting others to unreasonable risks and to compensate those who have been injured by unreasonably risky behavior. The greatest number of AIDS-related liability lawsuits has involved the receipt of HIV-infected blood and blood products. A second group has concerned the sexual transmission of HIV. A third group involves AIDS-related psychic distress. In these cases, plaintiffs have successfully sued and recovered damages for their fear of having contracted HIV.

Advances in Treatment Though the search for an AIDS vaccine has consumed many researchers, by 2003 no breakthroughs had appeared. However, other researchers have concentrated on ways of controlling AIDS through drug treatment regimens that require individuals to consume many different types of medications at the same time. These anti-AIDS "cocktails" undergo constant study and modification as researchers learn more about the working of HIV. The medications are from a family of drugs called protease inhibitors.

Survival rates have dramatically improved for those individuals using protease inhibitors, but other problems have also arisen. Some persons do not respond to these medications or the side effects from taking the drugs diminish the quality of life. Protease inhibitors, for many people, are intolerable because of nausea, diarrhea, vomiting, headache, kidney stones, and serious drug interactions with other medications. By 2003 researchers had found that serious side effects include increased risk of heart attack, abnormalities in fat distribution, an increased propensity toward diabetes, and abnormalities in cholesterol metabolism.

Cost is another concern associated with protease inhibitors. To be effective, protease inhibitors must be used in combination with at least two other anti-HIV drugs. Annual costs for this treatment ranges between $12,000-$15,000 per person. Those persons without private health insurance must rely on public programs such as the AIDS Drug Assistance Program (ADAP), a federally funded initiative to provide AIDS-related drugs to people with HIV. Most ADAP programs, which are administered by

states, have lacked the funding to enroll everyone in need.

International Issues By 2003 the international AIDS problem had become a crisis in Africa and parts of Asia. The united nations(UN) and the World Health Organization (WHO) have worked together to address the issues of prevention and treatment, but the statistics reveal grim conditions. In December 2002 a joint UN-WHO report disclosed that 42 million people in the world are living with HIV and AIDS. In 2002 five million people contracted HIV and over three million people died of AIDS. The situation is gravest in sub-Saharan Africa, where over 29 million adults and children are living with HIV and AIDS, contracted mainly through heterosexual contact. These figures stand in stark contrast to North America, where less than one million people are living with HIV and AIDS.

The growth of AIDS in Africa and Asia has raised worries about global political and economic stability. Governments in these ravaged countries have not been able to afford the anti-viral drugs. In 2002 pharmaceutical companies agreed to sell these drugs to these countries as generic drugs, dropping the cost from $12,000 to $300 a year per patient; yet even at these prices many governments would be hard pressed to purchase them.

In 2003, President george w. bush proposed spending $15 billion over five years to

support international AIDS prevention and the purchase of anti-viral drugs. The largest share of the money would be contributed directly by the United States to other countries, such as through programs sponsored by the U.S. Agency for International Development. The proposal would account for almost half the money in a global fund committed to fight HIV and AIDS.

further readings

ACLU. 1996. The Rights of People Who Are HIV Positive. Carbondale: Southern Illinois Univ. Press.

——. 1995a. AIDS and Civil Liberties. Briefing paper no. 13.

——. 1995b. Lesbian and Gay Rights. Briefing paper no. 18.

——. 1994. ACLU Wins Precedent-Setting Claim in AIDS Case; Federal Court Rules That ADA Covers AIDS Discrimination. Press release, November 21.

——. 1993. ACLU Files AIDS Discrimination Suit; Challenges South Carolina Insurance Risk Pool. Press release, April 6.

"Fighting Aids." February 10, 2003. PBS News Hour. Available online at <www.pbs.org> (accessed May 29, 2003).

Health and Human Services Department. Social Security Administration. 1991. A Guide to Social Security and SSI Disability Benefits for People with HIV Infection. Pub. no. 05-10020, September.

Jarvis, Robert M., et al., eds. 1996. AIDS Law in a Nutshell. 2d ed. Minneapolis, Minn.: West.

Rollins, Joe. 2002. "AIDS, Law, and the Rhetoric of Sexuality." Law & Society Review 36 (April).

White House. Office of the Press Secretary. 1994. Proclamation for World AIDS Day, November 30, 1994. Press release.

cross-references

Disability Discrimination; Discrimination; Food and Drug Administration; Gay and Lesbian Rights; Health Care Law; Patients' Rights; Physicians and Surgeons; Privacy.

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AIDS (Acquired Immunodeficiency Syndrome)

Introduction

Disease History, Characteristics, and Transmission

Scope and Distribution

Treatment and Prevention

Impacts and Issues

Primary Source Connection

BIBLIOGRAPHY

Introduction

First reported in the United States in 1981, acquired immunodeficiency syndrome (AIDS, also cited as acquired immune deficiency syndrome) has since become a major worldwide pandemic. Medical research has demonstrated that AIDS is caused by HIV (the human immunodeficiency virus), a retrovirus, so named because its genes are coded in ribonucleic acid (RNA) instead of the more common deoxyribonucleic acid (DNA). Essentially, the virus causes disease by killing or damaging cells of the human immune system. HIV gradually destroys a person's ability to battle infections and certain types of cancer. This loss of immune system functioning causes victims to be vulnerable to often-deadly opportunistic infections, which are caused by pathogens (diseasecausing organisms) that are usually harmless to healthy people.

Because the spread of the AIDS epidemic in the United States has been extensively tracked and analyzed, the most reliable information regarding its transmission, treatment, and prevention comes from United States-based research. However, it should be understood that the vast majority of people infected with HIV now live outside of the United States. While modes of transmission of HIV have been determined to be the same across the world, risk patterns among different peoples have varied according to cultural influences. For example, outside of Western Europe and North America, homosexual activity has been comparatively more circumscribed and suppressed; hence the major pattern of sexual transmission of HIV occurs among heterosexuals in non-Westernized countries. Although the HIV epidemic acquired its original momentum in the United States, the future focuses of the pandemic lie outside of the United States, mainly in the developing countries of Africa and Asia.

Disease History, Characteristics, and Transmission

The most common way to transmit HIV is by having unprotected sex with an infected partner. The virus can enter the body through the mucous membranes of the vagina, vulva, penis, rectum, or mouth during sexual activity.

HIV is transmitted by the exchange of bodily fluids such as blood, semen, and saliva. Therefore certain behaviors put people at risk for contracting HIV, including sharing drug syringes, anal, vaginal or oral sexual contact with an infected person without using a condom, and having sexual contact with someone with unknown HIV status.

Contact with Infected Blood

It is possible to contract HIV through contact with infected blood. This risk has given rise to extensive screening of donated blood for evidence of HIV infection, and also heat-treatment techniques to destroy HIV in blood products used in medical practice. Prior to these measures, HIV was transmitted through transfusions of contaminated blood or blood products such as serum, platelets, and clotting factors. Screening for HIV and heat treatment has practically eliminated the risk of getting HIV from such transfusions.

Contaminated Needles

One of the primary means of spreading infection with HIV is the sharing of syringes contaminated with very small quantities of blood among injection drug users from someone that has been infected with the virus.

There have also been rare cases of health care workers that have been infected by accidental punctures with needles or other medical instruments that have been contaminated by contact with patients, or, conversely, patients that have been infected by contaminated needles used by health care workers. In the health care setting, workers have been infected with HIV after being stuck with needles containing HIV-infected blood or, less frequently, after infected blood gets into a worker's open cut or a mucous membrane (for example, the eyes or inside of the nose). According to the CDC, there has been only one instance of patients being infected by a health care worker in the United States; this involved HIV transmission from one infected dentist to six patients. Investigations have been completed involving more than 22,000 patients of 63 HIV-infected physicians, surgeons, and dentists, and no other cases of this type of transmission have been identified in the United States.

Mother-to-child Transmission

Women can transmit HIV to their babies during pregnancy or birth. About one-quarter to one-third of HIV-positive pregnant women will pass the virus on to their babies. HIV can also be transmitted from infected mothers to babies through breast milk. Available drug treatment for the mother during pregnancy can significantly reduce the probability of such infection. Cesarean section delivery can further reduce mother-to-newborn infection rates to just one percent. Drug treatment and cesarean delivery has nearly eradicated mother-to-baby transmission of HIV in the United States. Use of these measures has increased worldwide. A study in Uganda sponsored by the U.S. National Institute of Allergy and Infectious Diseases (NIAID) and confirmed by independent research has established the safety and effectiveness of an affordable drug treatment with nevirapine (NVP) for preventing mother-to-newborn transmission of HIV. A single oral dose of this antiretroviral drug given to an HIV-infected woman in labor and another to her baby within three days of birth reduces the transmission rate of HIV by 50%.

Saliva and Other Bodily Fluids

Researchers have detected HIV in the saliva of infected people. Nevertheless, no evidence has yet been produced that the virus is transmitted by contact with saliva. Laboratory studies indicate that saliva has natural properties that limit the infectivity of HIV, and the concentration of virus in saliva has been found to be very low. Studies of HIV-positive individuals have found no evidence that the virus can be spread through saliva by kissing. Because of the potential for contact with blood during open-mouth kissing, the CDC recommends against engaging in this activity with a person known to be infected with HIV. However, the risk of acquiring HIV during open-mouth kissing is considered to be very low. CDC has investigated only one case of HIV infection that may be attributed to contact with blood during open-mouth kissing. Nevertheless, the mucous membrane of the mouth can be infected by HIV, and there have been documented instances of HIV transmission through oral sex.

Researchers have found no evidence that HIV is spread through sweat, tears, urine, or feces that is not contaminated with blood.

Biting

In 1997, the CDC published findings from a state health department investigation of an incident that suggested blood-to-blood transmission of HIV by a human bite. There have been other reports in the medical literature in which HIV appeared to have been transmitted by a bite. Severe trauma with extensive tissue tearing and damage and presence of blood were reported in each of these instances. Biting is not a common way of transmitting HIV. In fact, there are numerous reports of bites that did not result in HIV infection.

Casual Contact and Environmental Transmission

Extensive studies of families of HIV-infected people have shown conclusively that HIV is not spread through casual contact such as the sharing of food utensils, towels and bedding, swimming pools, telephones, or toilet seats. HIV is not spread by biting insects such as mosquitoes or bedbugs.

From the beginning of the AIDS epidemic, some people feared that HIV might be transmitted in other common ways, but no scientific evidence to support these fears has been found. If HIV were being transmitted through other routes (such as through air, water, or by insects), the pattern of reported AIDS cases would be much different from what has been observed. For example, if mosquitoes could transmit HIV infection, many more young children and adolescents would have been diagnosed with AIDS. All reported cases suggesting new or potentially unknown routes of transmission are thoroughly investigated by state and local health departments with the assistance, guidance, and laboratory support from the CDC. No additional routes of transmission have been recorded, despite a national sentinel system (an early warning system using animals or population data to detect the presence of disease) designed to detect just such an occurrence.

Households

Although HIV has been transmitted between family members in a household setting, such transmission is very rare. These transmissions are argued to have resulted from contact between skin or mucous membranes and infected blood. To prevent even such rare occurrences, precautions should be taken in all settings including the home to prevent exposures to the blood of persons who are HIV infected, at risk for HIV infection, or whose infection and risk status are unknown. CDC guidelines stipulate that 1) gloves should be worn during contact with blood or other body fluids that could possibly contain visible blood, such as urine, feces, or vomit; 2) cuts, sores, or breaks on both the care giver's and the patient's exposed skin should be covered with bandages; 3) hands and other parts of the body should be washed immediately after contact with blood or other body fluids, and surfaces soiled with blood should be disinfected appropriately; 4) practices that increase the likelihood of blood contact, such as sharing of razors and toothbrushes should be avoided; needles and other sharp instruments should be used only when medically necessary and handled according to recommendations for health-care settings.

Businesses and Other Settings There is no known risk of HIV transmission to co-workers, clients, or consumers from contact in industries such as food-service establishments. Food-service workers known to be infected with HIV need not be restricted from work unless they have other infections or illnesses (such as diarrhea or hepatitis A) for which any food-service worker, regardless of HIV infection status, should be restricted. The CDC recommends that all food-service workers follow recommended standards and practices of good personal hygiene and food sanitation.

In 1985, CDC issued routine precautions that all personal-service workers (such as hairdressers, barbers, cosmetologists, and massage therapists) should follow, even though there is no evidence of transmission from a personal-service worker to a client or vice versa. Instruments that penetrate the skin (such as tattooing and acupuncture needles, ear piercing devices) should be used once and disposed of or thoroughly cleaned and sterilized. Instruments not intended to penetrate the skin, but which may become contaminated with blood (for example, razors) should be used for only one client and disposed of or thoroughly cleaned and disinfected after each use. Personal-service workers can use the same cleaning procedures that are recommended for health care institutions.

The CDC reports no instances of HIV transmission through tattooing or body piercing, although hepatitis B virus has been transmitted during some of these practices. One case of HIV transmission from acupuncture has been documented. Body piercing (other than ear piercing) is relatively new in the United States, and the medical complications for body piercing appear to be greater than for tattoos. Healing of piercings generally will take weeks, and sometimes even months, and the pierced tissue could conceivably be abraded (torn or cut) or inflamed even after healing. Therefore, a theoretical HIV transmission risk does exist if the unhealed or abraded tissues come into contact with an infected person's blood or other infectious body fluid. Additionally, HIV could be transmitted if instruments contaminated with blood are not sterilized or disinfected between clients.

Sexually Transmitted Infections

Sexually transmitted infections (STI) such as syphilis, genital herpes, chlamydia, gonorrhea, or bacterial vaginosis appear to increase susceptibility to infection with HIV during sex with infected partners.

In the United States, condoms are regulated by the Food and Drug Administration (FDA) and condom manufacturers are required to test each latex condom for defects such as holes prior to packaging. The proper and consistent use of latex or polyurethane condoms when engaging in vaginal, anal, or oral sexual intercourse can greatly reduce the risk of acquiring or transmitting sexually transmitted diseases, including HIV infection.

Only latex or polyurethane condoms provide a highly effective mechanical barrier to HIV. In laboratories, viruses occasionally have been shown to pass through natural membrane (“skin” or lambskin) condoms, which may contain natural pores and are therefore not recommended for disease prevention, although they are documented to be effective for contraception. For condoms to provide maximum protection, they must be used consistently and correctly. Numerous studies among sexually active people have demonstrated that a properly used latex condom provides a high degree of protection against a variety of sexually transmitted diseases, including HIV infection.

Early Signs and Symptoms of HIV Infection

Most people show no early symptoms when initially infected with HIV. In a minority of cases, people may have a flulike illness within a month or two after exposure that could include fever, headache, fatigue, and swollen lymph nodes in the neck and groin. These symptoms usually disappear within a week to a month and are often attributed to some other viral infection. During this early period, people are very contagious, and HIV is present in large quantities in genital fluids.

Long-lasting, debilitating symptoms may not appear for 10 or more years after infection with HIV in adults, or within 2 years in children born with HIV infection. This latent period without symptoms varies greatly by individual, ranging from a few months to more than a decade. However, even during the asymptomatic (without symptoms) period, the virus is actively multiplying and destroying immune system cells, or can be dormant (inactive) within infected cells. The most readily apparent laboratory sign of HIV infection is a gradual decline in the blood concentration of CD4 positive T (CD4+) cells, which are cells the immune system's most important infection fighters. HIV slowly disables or destroys these cells without causing symptoms.

As the immune system deteriorates, various complications appear. The first persistent symptoms experienced by many persons with HIV include enlarged lymph nodes for more than three months, fatigue, weight loss, frequent fevers and sweats, persistent or frequent yeast infections (oral or vaginal), persistent skin rashes or flaky skin, pelvic inflammatory disease in women that does not respond to treatment, and short-term memory loss. Some people develop frequent and severe herpes infections that cause mouth, genital, or anal sores, or a resurgence of the dormant virus that causes chickenpox known as shingles. Children may fail to thrive and grow.

Acquired Immunodeficiency Syndrome (AIDS)

Usually after a long assault on the immune system, victims reach the most advanced stage of HIV infection, which is known as AIDS. The CDC, the agency responsible for tracking the AIDS epidemic in the United States, has developed official criteria that define AIDS. The CDC's definition of AIDS includes all HIV-infected people who have fewer than 200 CD4+ T cells per cubic millimeter of blood. (Healthy adults usually have CD4+ T-cell counts of 1,000 or more.) In addition, the definition includes 26 clinical conditions, mainly opportunistic infections that affect people with advanced HIV disease. In people with AIDS, these infections are generally severe and can be fatal because the immune system is so ravaged by HIV that the body loses its ability to fight off certain bacteria, viruses, fungi, parasites, and other microbes.

Common symptoms of opportunistic infections in both adults and children with AIDS include persistent coughing and shortness of breath, seizures, lack of coordination, difficult or painful swallowing, confusion or forgetfulness, severe and persistent diarrhea, fever, vision loss, nausea, abdominal cramps, vomiting, weight loss, extreme fatigue, and severe headaches. In addition, children may also have severe forms of the common childhood bacterial infections, such as conjunctivitis (pink eye), otitis media (ear infection), and tonsillitis.

In addition to opportunistic infections, people with AIDS are also prone to various cancers that are associated with persistent exposure to certain viruses such as Kaposi's sarcoma and cervical cancer, or cancers of the immune system known as lymphomas. These cancers are usually more aggressive and difficult to treat in people with AIDS.

As HIV infection progresses and the number of CD4+ T cells declines, people with CD4+ Tcells above 200 may experience some of the early symptoms of HIV disease. Conversely, others with their CD4+ T-cell count below 200 may have no symptoms. Victims frequently become so debilitated by the symptoms of AIDS that they are unable to work or do household chores. Other persons with AIDS may experience intermittent phases of life-threatening illness followed by periods during which they appear to be reasonably healthy.

WORDS TO KNOW

ANTIBODY: Antibodies, or Y-shaped immunoglobulins, are proteins found in the blood that help to fight against foreign substances called antigens. Antigens, which are usually proteins or polysaccharides, stimulate the immune system to produce antibodies. The antibodies inactivate the antigen and help to remove it from the body. While antigens can be the source of infections from pathogenic bacteria and viruses, organic molecules detrimental to the body from internal or environmental sources also act as antigens. Genetic engineering and the use of various mutational mechanisms allow the construction of a vast array of antibodies (each with a unique genetic sequence).

ASYMPTOMATIC: A state in which an individual does not exhibit or experience symptoms of a disease.

CD4+ T CELLS: CD4 cells are a type of T cell found in the immune system, which are characterized by the presence of a CD4 antigen protein on their surface. These are the cells most often destroyed as a result of HIV infection.

HIGHLY ACTIVE ANTIRETROVIRAL THERAPY (HAART): Highly active antiretroviral therapy (HAART) is the name given to the combination of drugs given to people with human immunodeficiency virus (HIV) infection to slow or stop the progression of their condition to AIDS (acquired human immunodeficiency syndrome). HIV is a retrovirus and the various components of HAART block its replication by different mechanisms.

LATENT INFECTION: An infection already established in the body but not yet causing symptoms, or having ceased to cause symptoms after an active period, is a latent infection.

OPPORTUNISTIC INFECTION: An opportunistic infection is so named because it occurs in people whose immune systems are diminished or are not functioning normally; such infections are opportunistic insofar as the infectious agents take advantage of their hosts' compromised immune systems and invade to cause disease.

PANDEMIC: Pandemic, which means all the people, describes an epidemic that occurs in more than one country or population simultaneously.

REPLICATE: To replicate is to duplicate something or make a copy of it. All reproduction of living things depends on the replication of DNA molecules or, in a few cases, RNA molecules. Replication may be used to refer to the reproduction of entire viruses and other microorganisms.

RETROVIRUS: Retroviruses are viruses in which the genetic material consists of ribonucleic acid (RNA) instead of the usual deoxyribonucleic acid (DNA). Retroviruses produce an enzyme known as reverse transcriptase that can transform RNA into DNA, which can then be permanently integrated into the DNA of the infected host cells.

SEXUALLY TRANSMITTED DISEASE (STD): Sexually transmitted diseases (STDs) vary in their susceptibility to treatment, their signs and symptoms, and the consequences if they are left untreated. Some are caused by bacteria. These usually can be treated and cured. Others are caused by viruses and can typically be treated but not cured. More than 15 million new cases of STD are diagnosed annually in the United States.

SENTINEL: Sentinel surveillance is a method in epidemiology where a subset of the population is surveyed for the presence of communicable diseases. Also, a sentinel is an animal used to indicate the presence of a disease within an area.

STRAIN: A subclass or a specific genetic variation of an organism.

A few people known to have been infected with HIV ten or more years ago have not developed symptoms of AIDS. Scientists are trying to ascertain what factors may account for this lack of progression to AIDS, such as whether their immune systems have particular characteristics, whether they were infected with a less aggressive strain of the virus or whether their genes may protect them from the effects of HIV. Researchers hope that understanding the body's natural method of controlling infection may produce ideas for protective HIV vaccines that can prevent the disease from progressing in the general population.

Diagnosis

Because early HIV infection often causes no symptoms, health care providers can usually diagnose it by testing blood for the presence of antibodies (disease-fighting proteins) to HIV. HIV antibodies generally do not reach noticeable levels in standard blood tests in the blood for one to three months or more following infection. In order to determine whether a person has been recently infected, health care providers can screen for the presence of HIV genetic material. Such direct screening of HIV is extremely critical in order to prevent transmission of HIV from recently infected individuals. Such individuals can discuss with health care providers when they should start treatment to help combat HIV and prevent the emergence of opportunistic infections. Early testing also alerts people to avoid high-risk behaviors that could transmit the virus to others. Health care providers often provide counseling to individuals who test HIV positive. People can be tested anonymously at many sites if they are concerned about confidentiality.

The diagnosis of HIV infection is established by using two different types of antibody tests: ELISA and Western Blot. Individuals who are highly likely to be infected with HIV, but have received negative results for both tests may request additional tests or may be told to repeat antibody testing at a later date, when antibodies are more likely to have developed.

Babies born to HIV infected mothers may or may not be infected with the virus, but all carry their mothers' antibodies to HIV for several months. If these babies lack symptoms, a doctor cannot make a definitive diagnosis of HIV infection using standard antibody tests. New technologies have been developed to more accurately determine HIV infection in infants between ages 3–15 months. Researchers are evaluating a number of blood tests to determine which ones can best diagnose HIV infection in infants younger than three months.

IN CONTEXT: CULTURAL CONNECTIONS

Following the discovery of AIDS, scientists attempted to identify the virus that causes the disease. In 1983–84, two scientists and their teams reported isolating HIV, the virus that causes AIDS. One was French immunologist Luc Montagnier (1932–), working at the Pasteur Institute in Paris, and the other was American immunologist Robert Gallo (1937–) at the National Cancer Institute in Bethesda, Maryland. Both identified HIV as the cause of AIDS and showed the pathogen to be a retrovirus, meaning that its genetic material is RNA, instead of DNA. Following the discovery, a dispute ensued over who made the initial discovery, but today Gallo and Montagnier are credited as co-discoverers.

Scope and Distribution

Since 1981, more than 900,000 cases of AIDS have been reported in the United States. At least as many Americans may be infected with HIV, 25% of whom are not yet aware of their infection. AIDS has been spreading most rapidly among non-Caucasian populations and is one of the foremost killers of adult African-American males between the ages 25–44. The CDC has produced statistics showing that AIDS affects nearly seven times more African-Americans and three times more Hispanics than whites in the United States.

Worldwide, the AIDS epidemic has killed more than 25 million people since 1981, and an estimated 40 million people are living with AIDS today. Young people, under 25 years old, now account for more than half of all new HIV infections.

Treatment and Prevention

When AIDS first appeared in the United States, there were no medicines that were effective against HIV and few treatments existed for the associated opportunistic diseases. Within a relatively short time after the discovery of HIV, researchers began to develop drugs to fight both HIV infection and its associated infections and cancers.

The first group of drugs used to treat HIV infection, called nucleoside reverse transcriptase (RT) inhibitors, interruptsan early stage of the virus as it replicates (duplicates). These drugs slow the spread of HIV in the body and delay the start of opportunistic infections. This class of drugs, called nucleoside analogs, includes AZT (azidothymidine), ddC (zalcitabine), ddI (dideoxyinosine), d4T (stavudine), 3TC (lamivudine), abacavir, tenofovir, and emtricitabine.

Physicians can also prescribe non-nucleoside reverse transcriptase inhibitors (NNRTIs) to treat HIV infection, such as delavridine, nevirapine, and efravirenz, often in combination with other antiretroviral drugs.

A second class of drugs for treating HIV infection called protease inhibitors was later approved. Protease inhibitors interrupt the virus from replicating itself at a later step in its life cycle. They include ritonavir, saquinivir, indinavir, amprenivir, nelfinavir, lopinavir, atazanavir, and fosamprenavir.

A third new class of drugs known as HIV fusion inhibitors includes enfuvirtide, the first approved fusion inhibitor, which works by interfering with HIV-1's ability to enter into cells by blocking the merging of the virus with the cell membranes. This inhibition blocks HIV's ability to enter and infect the human immune cells. Enfuvirtide is designed for use in combination with other anti-HIV treatments. It reduces the level of HIV infection in the blood and may be active against HIV that has become resistant to current antiviral treatment schedules.

IN CONTEXT: TRENDS AND STATISTICS

The list below reflects data on the percentage (%) of all deaths in children under 5 years of age due to HIV/AIDS as reported by World Health Organization in February 2007.

Data is shown for countries reporting approximately that 4% or more of children under 5 years of age die from AIDS/HIV

  • Burkina Faso: 4.00%
  • Chad: 4.06%
  • Trinidad and Tobago: 4.69%
  • Ukraine: 4.95%
  • Nigeria: 4.96%
  • Rwanda: 4.99%
  • Bahamas: 5.34%
  • Côte d'Ivoire: 5.59%
  • Ghana: 5.74%
  • Togo: 5.78%
  • Jamaica: 6.09%
  • Thailand: 6.18%
  • Eritrea: 6.21%
  • Honduras: 6.28%
  • Cameroon: 7.24%
  • Equatorial Guinea: 7.39%
  • Uganda: 7.67%
  • Guyana: 7.68%
  • Burundi: 8.00%
  • Haiti: 8.28%
  • United Republic of Tanzania: 9.29%
  • Congo: 9.33%
  • Gabon: 10.10%
  • Central African Republic: 12.40%
  • Mozambique: 12.94%
  • Malawi: 14.04%
  • Kenya: 14.57%
  • Zambia: 16.12%
  • Zimbabwe: 40.59%
  • Swaziland: 47.00%
  • Namibia: 52.96%
  • Botswana: 53.85%
  • Lesotho: 56.19%
  • South Africa: 57.08%

SOURCE: World Health Organization

Because HIV can become resistant to any of these drugs, health care providers must use a combination treatment to effectively suppress the virus. When multiple drugs (three or more) are used in combination, it is referred to as highly active antiretroviral therapy, or HAART, and can be used by people who are newly infected with HIV as well as people with AIDS. Researchers have credited HAART as being a major factor in significantly reducing the number of deaths from AIDS in the U.S. While HAART is not a cure for AIDS, it has greatly improved the health of many people with AIDS and reduces the amount of virus circulating in the blood to nearly undetectable levels. Researchers, however, have shown that HIV remains present in some places in the body, such as the lymph nodes, brain, testes, and retina of the eye, even in people who have been treated.

Opportunistic Infections A number of available drugs help treat the opportunistic infections of AIDS. These drugs include foscarnet and ganciclovir to treat CMV (cytomegalovirus) eye infections, fluconazole to treat yeast and other fungal infections, and TMP/SMX (trimethoprim/sulfamethoxazole) or pentamidine to treat a pneumonia known as PCP (Pneumocystis carinii pneumonia) that is sometimes associated with AIDS.

Cancers Health care providers use radiation, chemotherapy, or injections of alpha interferon, a genetically engineered protein that occurs naturally in the human body, to treat Kaposi's sarcoma or other cancers associated with HIV infection.

Prevention

In the absence of a vaccine for HIV, the only means to prevent infection by the virus is to avoid behaviors that put people at risk of infection, such as sharing needles and having unprotected sex. Because many people infected with HIV have no symptoms, there is no way of knowing with certainty whether a sexual partner is infected unless he or she has repeatedly tested negative for the virus and has not engaged in any risky behavior. Abstaining from having sex offers the most protection from AIDS. Using male latex condoms or female polyurethane condoms have been shown in prospective studies to offer partial protection during oral, anal, or vaginal sex. Only water-based lubricants should be used with male latex condoms.

Although some laboratory evidence shows that spermicides can kill HIV, researchers have not found that these products can prevent the transmission of HIV during sex.

Ongoing Research

Research is ongoing in all areas of HIV infection, including developing and testing preventive HIV vaccines and new treatments for HIV infection and AIDS-associated opportunistic infections. Researchers also are trying to determine exactly how HIV damages the immune system. Recently, an electron micrograph was taken of HIV binding to a cell wall and is being examined for precise information about how the virus infects healthy cells. Such research is identifying new and more effective targets for drugs and vaccines. Investigators also continue to trace how the disease progresses in different people.

Current research also includes testing chemical barriers, such as topical microbicides (germ-killing compounds) that people can use in the vagina or in the rectum during sex to help prevent HIV transmission. Scientists are also examining the effectiveness of other ways of preventing HIV transmission, such controlling other sexually transmitted infections like chlamydia that have a role in making HIV easier to contract.

IN CONTEXT: ANTIRETROVIRAL THERAPY COVERAGE

The list below reflects selected data on antiretroviral therapy coverage from countries selected across the spectrum of data (ranked lowest to highest in terms of percentage of those estimated to need antiretroviral therapy who have actual access to the treatment) as reported by the World Health Organization in February 2007.

Selected non-reporting countries, or countries for which data was otherwise not available, included the Republic of Korea, Singapore, Afghanistan, and Iraq.

  • Sudan: 1% of persons estimated to need ARV therapy have access to the treatment (data reported: Dec 2005)
  • Nepal: 1% (Dec 2005)
  • Bangladesh: 1% (Dec 2005)
  • Somalia: 1% (Dec 2005)
  • Guinea-Bissau: 1% (Dec 2005)
  • Pakistan: 2% (Dec 2005)
  • Sierra Leone: 2% (Dec 2005)
  • Central African Republic: 3% (Dec 2005)
  • Philippines: 5% (Dec 2005)
  • Russian Federation: 5% (Dec 2005)
  • Belarus: 5% (Dec 2005)
  • Nigeria: 6% (Dec 2005)
  • Angola: 6% (Dec 2005)
  • Sri Lanka: 6% (Dec 2005)
  • Ukraine: 6 % (Dec 2005)
  • India: 7% (Dec 2005)
  • United Republic of Tanzania: 7 % (Dec 2005)
  • Ghana: 7% (Dec 2005)
  • Ethiopia: 7% (Dec 2005)
  • Myanmar: 7% (Dec 2005)
  • Zimbabwe: 8% (Dec 2005)
  • Mozambique: 9% (Dec 2005)
  • Gambia: 9% (Dec 2005)
  • Turkey: 9% (Dec 2005)
  • Iran (Islamic Republic of): 9% (Dec 2005)
  • Egypt: 12% (Dec 2005)
  • Viet Nam: 12% (Dec 2005)
  • South Africa: 21% (Dec 2005)
  • Kenya: 24% (Dec 2005)
  • China: 25% (Dec 2005)
  • Swaziland: 31% (Dec 2005)
  • Tunisia: 34% (Dec 2005)
  • Cambodia: 36% (Dec 2005)
  • Rwanda: 39% (Dec 2005)
  • Guatemala: 43% (Dec 2005)
  • Colombia: 44% (Dec 2005)
  • Senegal: 47% (Dec 2005)
  • Guyana: 50% (Dec 2005)
  • Uganda: 51% (Dec 2005)
  • Mexico: 71% (Dec 2005)
  • Canada: 75% (Dec 2005)
  • Israel: 75% (Dec 2005)
  • Italy: 75% (Dec 2005)
  • New Zealand: 75% (Dec 2005)
  • United Kingdom: 75% (Dec 2005)
  • United States of America: 75% (Dec 2005)
  • Costa Rica: 80% (Dec 2005)
  • Argentina: 81% (Dec 2005)
  • Brazil: 83% (Dec 2005)
  • Venezuela (Bolivarian Republic of): 84% (Dec 2005)
  • Botswana: 85% (Dec 2005)
  • Cuba: 100% (Dec 2005)

SOURCE: World Health Organization, Progress on global access to HIV anti-retroviral therapy. A report on “3 by 5” and beyond. Geneva, World Health Organization and Joint United Nations Programme on HIV/AIDS, March 2006.

Impacts and Issues

As the AIDS pandemic nears its 30th year, the number of people infected with HIV continues to climb steadily. Approximately two thirds of infected persons live in Africa, where the epidemic grew exponentially during the decade of the 1990s, and one fifth are in Asia, where the epidemic has been growing most rapidly in recent years. By the end of 2006, more than 40 million people worldwide were living with HIV infection. Worldwide funding from public and private sources to combat the epidemic has similarly risen dramatically, in an increasingly urgent effort to reverse the growth trajectory of the epidemic. Recent estimates of worldwide HIV infections and deaths have been revised downward, but these downward revisions do not reflect the uncertainty and unreliability of global HIV statistics outside of the major industrial nations.

Analysis of the reliable data has shown that the primary modes of HIV transmission have not changed significantly over time from those outlined above: unprotected heterosexual intercourse, unprotected anal sex between men, injection-drug use, unsafe medical injections and blood transfusions, and transmission from mother to child during pregnancy, labor and delivery, or breast-feeding. Direct blood contact, such as the sharing of drug-injection equipment, is by far the most efficient means of transmitting the virus. However the specific features of the epidemic vary among regions and within countries. Globally, in the World Health Report 2004, the World Health Organization (WHO) states that “unprotected sexual intercourse between men and women is the predominant mode of transmission of the virus.” This report also states that “In sub-Saharan Africa and the Caribbean, women are at least as likely as men to become infected.” In India, a large proportion of infected persons are prostitutes and long-haul truck drivers. In areas of China, India, Thailand, and Vietnam, HIV transmission is being fueled primarily by injection-drug use. In other parts of Southeast Asia, Cambodia, Myanmar, Thailand, and Vietnam, men having sex with prostitutes are a major factor.

IN CONTEXT: DISEASE IN DEVELOPING NATIONS

The World Health Organization (WHO) states that “in the developing world, 6 million people infected with HIV need access to antiretroviral (ARV) therapy. Only 300,000 have such access. To address the HIV/AIDS crisis, the World Health Organization, with the Joint United Nations Programme on AIDS (UNAIDS) and other partners, has committed itself to having 3 million people living with HIV/AIDS in developing countries on ARV treatment by the end of 2005.”

SOURCE: World Health Organization

The most recent statistics underline global disparities in AIDS deaths. Absent treatment with antiretroviral drugs, it usually takes about 10 years for HIV infection to progress to AIDS. More than two million people in sub-Saharan Africa died of AIDS in 2006 (accounting for three-quarters of the worldwide total). By comparison, in Western Europe, where drug treatment is widely available, only a few thousand people died of AIDS. In the most recent year of statistics, more than 12 million children in sub-Saharan Africa were orphaned by AIDS. Because the rapid growth of the epidemic is more recent in Asia, the number of deaths from AIDS has been comparatively lower than in Africa, given the number of infected people and a similar lack of drug treatment. Still, tens of thousands of people have died in Thailand and China each year in the past several years and death rates are increasing as asymptomatic infections acquired in the past decade progress to full-blown AIDS. Sub-Saharan Africa continues to have the most mother-to-child transmission of the virus, where more than a half-million children died of AIDS in 2005.

Increasingly the mantra of the international community is access for all to effective antiretroviral therapy. Only two approaches to containing the epidemic have been effective: preventing new HIV infections and providing antiretroviral treatment to victims of HIV. As there is no AIDS vaccine, prevention efforts focus on education about sexual and other practices, behavioral change, and outreach to marginalized groups of people, including injection-drug users and sex workers and their clients. Many infected people do not realize that they are infected; others may not seek available care because of the stigma of being HIV positive. Cambodia and Thailand are cited as examples of nations that have prevention programs promoting increased condom use by prostitutes and their clients that have been demonstrably effective.

Even if ambitious WHO goals for increasing access to antiretroviral treatment are successful, and despite substantial progress toward these goals, less than 10 percent of the people globally that need treatment for HIV infection are receiving it. A few countries such as Botswana, Senegal, and Uganda in Africa, and Brazil in South America are doing better. Brazil has a universal program for the distributing antiretroviral medications. Botswana, with one of the highest HIV infection rates in the world, has a program of routine HIV testing and is also successfully expanding access to drug treatment.

In summary, there is some evidence that the global HIV epidemic is starting to slow slightly, both in the rate of new infections and in the AIDS death rate. Behavioral change based on detailed knowledge of the means of viral transmission has been successful in saving millions of lives, and access to modern drug therapy has and can save millions more. Although the ultimate eradication of HIV infection remains a cherished goal of the worldwide medical research community, efforts to change behavior and expand access to currently available treatments will save untold millions of lives until the enigma of HIV infection is finally solved.

Primary Source Connection

In the commentary that follows, Nicholas D. Kristof describes the failures of political and health policies during the first quarter century of the AIDS pandemic in the context of family impacts in Swaziland. At the time of publication, Nicholas D. Kristof served as a columnist for the The New York Times since November 2001. In 1990, Kristof shared a Pulitzer Prize for coverage of China's Tiananmen Square uprising and democracy movement. In 2006, Mr. Kristof won a second Pulitzer for commentary.

See AlsoAIDS: Origin of the Modern Pandemic; Bloodborne Pathogens; Epidemiology; Opportunistic Infection; Public Health and Infectious Disease; Sexually Transmitted Diseases.

BIBLIOGRAPHY

Books

Johanson, Paula. HIV and AIDS (Coping in a Changing World). New York: Rosen, 2007.

World Health Organization. Preventing HIV/AIDS in Young People. Geneva: WHO, 2006.

Periodicals

Steinbrook R. Global Health: The AIDS Epidemic in 2004. New England Journal of Medicine 2004; 351:115–117, Jul 8, 2004.

Steinbrook R. HIV in India—The Challenges Ahead. New England Journal of Medicine 2007; 356: 1197–1201, Mar 22, 2007.

Steinbrook R. HIV in India—A Complex Epidemic. New England Journal of Medicine 2007; 356: 1089–1093, Mar 15, 2007.

Web Sites

AIDS info. <http://aidsinfo.nih.gov> (accessed April 9, 2007).

NIH Vaccine Research Center. “Become an HIV Vaccine Study Volunteer.” <http://www.niaid.nih.gov/vrc/clintrials/clin_steps.htm%20%20%20> (accessed April 9, 2007).

Kenneth T. LaPensee

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AIDS

In June 1981 scientists published the first report of a mysterious and fatal illness that initially appeared to affect only homosexual men. Subsequent early reports speculated that this illness resulted from homosexual men's sexual activity and, possibly, recreational drug use. In the months that followed, however, this same illness was diagnosed in newborns, children, men, and women, a pattern strongly suggesting a blood-borne infection as the cause of the observed illness. The illness was initially identified by several terms (e.g., "gay bowel syndrome," "lymphadenopathy virus (LAV)," and AIDS-associated retrovirus (ARV), but by 1982 this disease came to be known as acquired immune deficiency syndrome (AIDS) because of the impact of the infectious agent, human immunodeficiency virus (HIV), on an infected person's immune system. Since about 1995 the term HIV disease has been used to describe the condition of HIV-infected persons from the point of early infection through the development of AIDS.

Over the next two decades AIDS became one of the leading causes of death in the United States and in other parts of the world, particularly in persons younger than forty-five years of age. Since the 1990s in the United States AIDS has come to be viewed as an "equal opportunity" disease, because it affects persons of all colors, class, and sexual orientation. Despite the evolution of major treatment advances for HIV infection and AIDS, HIV disease has been the cause of death for about 450,000 persons living in the United States since the onset of the epidemic. In addition, an estimated 800,000 to 900,000 Americans are infected with the virus that causes AIDSand perhaps as many as 300,000 are unaware of their infection. Better treatments for HIV infection have resulted in a reduction in the number of deaths from AIDS and an increase in the number of persons living with HIV infection.

The cause of AIDS was identified in 1983 by the French researcher Luc Montagnier as a type of virus known as a "retrovirus." This newly identified retrovirus was eventually called "human immunodeficiency virus," or HIV. Scientists have established HIV as the cause of AIDS, even though a small group of individuals have questioned the link between HIV and AIDS. An HIV-infected person who meets specific diagnostic criteria (i.e., has one or more of the twenty-five AIDS-defining conditions indicative of severe immunosuppression and/or a seriously compromised immune system) is said to have AIDS, the end stage of a continuous pathogenic process. Multiple factors influence the health and functioning of HIV-infected persons. For example, some persons who meet the diagnostic criteria for AIDS may feel well and function normally, while other HIV-infected persons who do not meet the diagnostic criteria for AIDS may not feel well and have reduced functioning in one or more areas of their lives.

While drugs are now available to treat HIV infection or specific HIV-related conditions, these treatments are expensive and unobtainable to most of the world's infected individuals, the vast majority of whom live in poor, developing nations. Thus the most important and effective treatment for HIV disease is prevention of infection. Preventive measures are challenging because sexual and drug use behaviors are difficult to change; certain cultural beliefs that influence the potential acquisition of infection are not easily modified; many persons at highest risk lack access to risk-reduction education; and many persons (especially the young) deny their vulnerability to infection and engage in behaviors that place them at risk of infection.

An individual may be infected with HIV for ten years or more without symptoms of infection. During this period, however, the immune system of the untreated person deteriorates, increasing his or her risk of acquiring "opportunistic" infections and developing certain malignancies. While HIV disease is still considered a fatal condition, the development in the 1990s of antiretroviral drugs and other drugs to treat opportunistic infections lead many infected individuals to hope that they can manage their disease for an extended period of time. Unfortunately, the view that HIV disease is a "chronic" and "manageable" condition (as opposed to the reality that it is a fatal condition) may lead persons to engage in behaviors that place them at risk of infection. In the United States, for example, epidemiologists have noted an upswing in the number of HIV infections in young homosexual men who, these experts believe, engage in risky behaviors because HIV disease has become less threatening to them. These individuals are one generation removed from the homosexual men of the 1980s who saw dozens of their friends, coworkers, and neighbors die from AIDS and thus may not have experienced the pain and grief of the epidemic's first wave.

Origin of HIV

The origin of the human immunodeficiency virus has interested scientists since the onset of the epidemic because tracing its history may provide clues about its effects on other animal hosts and on disease treatment and control. While HIV infection was first identified in homosexual men in the United States, scientists have learned from studies of stored blood samples that the infection was present in human hosts yearsand perhaps decadesbefore 1981. However, because the number of infected individuals was small and the virus was undetectable prior to 1981, a pattern of disease went unrecognized. HIV disease may have been widespread, but unrecognized, in Africa before 1981.

While a number of theories, including controversial conspiracy theories, have been proposed to explain the origin of HIV and AIDS, strong scientific evidence supports the view that HIV represents a cross-species (zoonosis) infection evolving from a simian (chimpanzee) virus in Southwest Africa between 1915 and 1941. How this cross-species shift occurred is unclear and a topic of considerable debate. Such an infectious agent, while harmless in its natural host, can be highly lethal to its new host.

Epidemiology of HIV Disease

Because HIV has spread to every country of the world, it is considered a pandemic. By the end of 2001 an estimated 65 million persons worldwide had been infected with HIV and of these, 25 million had died. An estimated 14,000 persons worldwide are infected every day. Most (95%) of the world's new AIDS cases are in underdeveloped countries. About 70 percent of HIV-infected persons live in sub-Saharan Africa. Globally 1 in 100 people are infected with HIV. The effects of HIV disease on the development of the world have been devastating. Millions of children in developing nations are infected and orphaned. The economies of some developing nations are in danger of collapse; and some nations risk political instability because of the epidemic.

Over the past decade an estimated 40,000 persons living in the United States have become infected with HIV every year, a figure that has remained relatively stable. Between 1981 and 2000 more than 774,000 cases of AIDS were reported to the Centers for Disease Control and Prevention (CDC). Of these cases, more than 82 percent were among males thirteen years and older, while more than 16 percent were among females thirteen years and older. Less than 2 percent of AIDS cases were among children younger than thirteen years of age. More than 430,000 persons living in the United States had died from AIDS by the end of 1999. The annual number of deaths among persons with AIDS has been decreasing because of early diagnosis and improved treatments for opportunistic infections and HIV infection.

The epidemiologic patterns of HIV disease have changed significantly since the onset of the epidemic. In 1985, for example, 65 percent of new AIDS cases were detected among men who have sex with other men (MSM). Since 1998 only about 42 percent of new AIDS cases have been detected among MSM, although the rate of new infections in this group remains high. Increasing numbers of new AIDS cases are attributed to heterosexual contact (but still only about 11 percent of the cumulative AIDS cases) and among injection drug users (about 25 percent of cumulative AIDS cases). In 2002 women, who are primarily infected through heterosexual contact or injection drug use, account for about 30 percent of all new HIV infections, a dramatic shift in the United States since 1981. In developing parts of the world men and women are infected in equal numbers.

In the United States new HIV infections and AIDS disproportionately affect minority populations and the poor. Over half (54%) of new HIV infections occur among African Americans, who represent less than 15 percent of the population. Hispanics are disproportionately affected as well. African-American women account for 64 percent (Hispanic women, 18%) of new HIV infections among women. African-American men account for about half of new HIV infections among men, with about equal numbers (18%) of new infections in white and Hispanic men. HIV infections in infants have been dramatically reduced because of the use of antiretroviral drugs by HIV-infected women who are pregnant.

HIV Disease: The Basics

There are two major types of human immunodeficiency virus: HIV-1 and HIV-2. HIV-1 is associated with most HIV infections worldwide except in West Africa, where HIV-2 is prevalent. Both types of viruses may be detected through available testing procedures. HIV is a retrovirus and member of a family of viruses known as lentiviruses, or "slow" viruses. These viruses typically have a long interval between initial infection and the onset of serious symptoms. Lentiviruses frequently infect cells of the immune system. Like all viruses, HIV can replicate only inside cells, taking over the cell's machinery to reproduce. HIV, once inside a cell, uses an enzyme called reverse transcriptase to convert ribonucleic acid (RNA) into deoxyribonucleic acid (DNA), which is incorporated into the host cell's genes. The steps in HIV replication include: (1) attachment and entry; (2) reverse transcription and DNA synthesis; (3) transport to nucleus; (4) integration; (5) viral transcription; (6) viral protein synthesis; (7) assembly and budding of virus; (8) release of virus; and (9) maturation. In addition to rapid replication, HIV reverse transcriptase enzyme makes many mistakes while making DNA copies from HIV RNA, resulting in multiple variants of HIV in an individual. These variants may escape destruction by antibodies or killer T cells during replication.

The immune system is complex, with many types of defenses against infections. Some parts of this system have key coordinating roles in mobilizing these defenses. One such key is the CD4+ T-lymphocyte (also known as CD4+ T cell and T-helper cell), a type of lymphocyte that produces chemical "messengers." These messengers strengthen the body's immune response to infectious organisms. The cell most markedly influenced by HIV infection is the CD4+ T-lymphocyte. Over time HIV destroys these CD4+ T cells, thus impairing the immune response of people with HIV disease and making them more susceptible to secondary infections and some types of malignant tumors.

If HIV infection progresses untreated, the HIV-infected person's number of CD4+ T-lymphocytes declines. Therefore, early in the course of HIV disease the risk for developing opportunistic infections is low because the CD4+ T-lymphocytes may be nearly normal or at least adequate to provide protection against pathogenic organisms; however, in untreated individuals the risk of infection increases as the number of CD4+ cells falls. The rate of decline of CD4+ T lymphocyte numbers is an important predictor of HIV-disease progression. People with high levels of HIV in their bloodstream are more likely to develop new AIDS-related symptoms or die than individuals with lower levels of virus. Thus early detection and treatment of HIV infection and routine use of blood tests to measure viral load are critical in treating HIV infection. HIV may also directly infect other body cells (e.g., those of the brain and gastrointestinal tract), resulting in a range of clinical conditions. When cells at these sites are infected with HIV, such problems as dementia and diarrhea may result; thus even if HIV-infected persons do not develop an opportunistic infection or malignancy, they may experience a spectrum of other clinical problems that require medical treatment or interfere with their quality of life.

How Is HIV Spread?

The major known ways by which HIV infection is spread are: (1) intimate sexual contact with an HIV-infected person; (2) exposure to contaminated blood or blood products either by direct inoculation, sharing of drug apparatus, transfusion, or other method; and (3) passage of the virus from an infected mother to her fetus or newborn in utero, during labor and delivery, or in the early newborn (including through breast-feeding). Some health care workers have become occupationally infected with HIV, but these numbers are small in light of the millions of contacts between health care workers and persons with HIV infection. Most occupationally acquired HIV infections in such workers have occurred when established "universal precautions" have not been followed.

HIV-infected blood, semen, vaginal fluid, breast milk, and other bodily fluids containing blood have been proven to have the potential to transmit HIV. While HIV has been isolated from other cells and tissues, the importance of these bodily fluids in transmission is not entirely clear. Health care workers may come into contact with other bodily fluids that can potentially transmit HIV. While HIV has been transmitted between members in a household setting, such transmission is extremely rare. There are no reports of HIV being transmitted by insects; by nonsexual bodily contact (e.g., handshaking); through closed mouth or social kissing; or by contact with saliva, tears, or sweat. One cannot be HIV-infected by donating blood. Transfusion of blood products can pose a risk of infection, but the risk is low in the United States, where all such products are carefully tested.

Several factors (called "cofactors") may play a role in the acquisition of HIV infection, influence its transmission, affect development of clinical signs and symptoms, and influence disease progression. Cofactors that have been mentioned in scientific literature include anal receptive sex resulting in repeated exposure to absorbed semen; coexistence of other infections (e.g., syphilis, hepatitis B); injection and recreational drug use; use of immunosupressant drugs (e.g., cocaine, alcohol, or amyl/butyl nitrites); douching or enemas before sexual intercourse; malnutrition; stress; age at time of seroconversion; genetic susceptibility; multiple sexual partners; and presence of genital ulcers.

Preventing HIV Infection

HIV infection is almost 100 percent preventable. HIV infection may be prevented by adhering to the following measures:

  • engaging in one-partner sex where both participants are HIV-negative and are maintaining a sexual relationship that only involves those two participants;
  • using latex or polyurethane condoms properly every time during sexual intercourse, including oral sex;
  • not sharing needles and syringes used to inject drugs or for tattooing or body piercing;
  • not sharing razors or toothbrushes;
  • being tested for HIV if one is pregnant or considering pregnancy;
  • prohibiting oneself from breast-feeding if HIV-positive; and
  • calling the CDC National AIDS Hotline at 1-800-342-AIDS (2437) for more information about AIDS prevention and treatment (or by contacting www.cdc.gov/hiv to access the CDC Division of HIV/AIDS for information).

What Happens after Infection with HIV?

Following infection with HIV the virus infects a large number of CD4+ cells, replicating and spreading widely, and producing an increase in viral burden in blood. During this acute stage of infection, which usually occurs within the first few weeks after contact with the virus, viral particles spread throughout the body, seeding various organs, particularly the lymphoid organs (lymph nodes, spleen, tonsils, and adenoids). In addition, the number of CD4+ T cells in the bloodstream decreases by 20 to 40 percent. Infected persons may also lose HIV-specific CD4+ T cell responses that normally slow the replication of viruses in this early stage. Within a month of exposure to HIV the infected individual's immune system fights back with killer T cells (CD8+ T cells) and B-cell antibodies that reduce HIV levels, allowing for a rebound of CD4+ T cells to 80 to 90 percent of their original level. The HIV-infected person may then remain free of HIV-related symptoms for years while HIV continues to replicate in the lymphoid organs seeded during the acute phase of infection. Also at this point many infected persons experience an illness (called "primary" or "acute" infection) that mimics mononucleosis or flu and usually lasts two to three weeks.

In untreated HIV-infected persons, the length of time for progression to disease varies widely. Most (80 to 90 percent) HIV-infected persons develop AIDS within ten years of initial infection; another 5 to 10 percent of infected persons progress to AIDS within two to three years of HIV infection; about 5 percent are generally asymptomatic for seven to ten years following infection and have no decline in CD4+ T lymphocyte counts. Efforts have been made to understand those factors that affect disease progression, including viral characteristics and genetic factors. Scientists are also keenly interested in those individuals who have repeated exposures to HIV (and may have been acutely infected at some point) but show no clinical evidence of chronic HIV infection.

Testing and Counseling

Testing for HIV infection has complex social, ethical, legal, and health implications. HIV testing is done for several reasons: to identify HIV-infected persons who may benefit from early medical intervention; to identify HIV-negative persons who may benefit from risk reduction counseling; to provide for epidemiological monitoring; to engage in public health planning. Individuals who seek HIV testing expect that test results will remain confidential, although this cannot be entirely guaranteed. Anonymous testing is widely available and provides an additional measure of confidentiality.

HIV testing has been recommended for those who consider themselves at risk of HIV disease, including:

  • women of childbearing age at risk of infection;
  • persons attending clinics for sexually transmitted disease and drug abuse;
  • spouses and sex- or needle-sharing partners of injection drug users;
  • women seeking family planning services;
  • persons with tuberculosis;
  • individuals who received blood products between 1977 and mid-1995; and
  • others, such as individuals with symptoms of HIV-related conditions; sexually active adolescents; victims of sexual assault; and inmates in correctional facilities.

Detection of HIV antibodies is the most common approach to determine the presence of HIV infection, although other testing approaches can detect the virus itself. Testing for HIV infection is usually accomplished through standard or rapid detection (results are obtained in five to thirty minutes) of anti-HIV antibodies in blood and saliva. The most common types of antibody test for HIV serodiagnosis include the enzyme-linked immunosorbent assay (ELISA), the Western blot, immunofluorescence, radioimmuno-precipitation, and hemagglutination. These tests do not directly measure the presence of the virus but rather the antibodies formed to the various viral proteins. One home testing kitthe Home Access HIV-1 Test Systemis approved by the U.S. Food and Drug Administration. Oral and urine-based tests are available for rapid screening in medical offices but are typically followed up by one or more tests for confirmation. Most tests used to detect HIV infection are highly reliable in determining the presence of HIV infection, but false-positive and false-negative results have been documented by Niel Constantine and other health care professionals.

Testing for HIV infection should always include pre- and posttest counseling. Guidelines for such testing have been published by the CDC. Pretest counseling should include information about the test and test results, HIV infection, and AIDS; performance of a risk assessment and provision of information about risk and risk reduction behaviors associated with the transmission of HIV; discussion about the consequences (i.e., medical care, pregnancy, employment, insurance) of a positive or negative result for the person being tested and for others (family, sexual partner(s), friends); and discussion about the need for appropriate follow-up in the event of positive test results. Posttest counseling is dependent upon test results, but generally includes provision of test results, emotional support, education, and, when appropriate, referral for medical or other forms of assistance.

Clinical Manifestations of HIV Disease

The clinical manifestations of HIV vary greatly among individuals and depend upon individual factors and the effectiveness of medical intervention, among other factors. Primary infection may also offer the first opportunity to initiate antiretroviral therapy, although all experts do not agree that such therapy should be initiated at this stage of the infection. The symptom-free period of time following primary infection has been extended in many infected persons by the introduction of highly active antiretroviral therapy (HAART). Many HIV-infected persons, especially those who do not receive antiretroviral therapy, those who respond poorly to such therapy, and those who experience adverse reactions to these drugs, will develop one or more opportunistic conditions, malignancies, or other conditions over the course of their disease.

Opportunistic Infections

Prior to the HIV epidemic, many opportunistic infections (OIs) seen in HIV-infected persons were not commonly encountered in the health care community. Many of the organisms responsible for these OIs are everywhere (ubiquitous) in the environment and cause little or no disease in persons with competent immune systems. However, in those who are immunocompromised, these organisms can cause serious and life-threatening disease. Since the introduction of HAART the incidence of HIV-related opportunistic infections and malignancies has been declining. The epidemiological patterns of at least some of these opportunistic diseases vary by region and country. Ideally, treatment of OIs is aimed at prevention of infections, treatment of active infections, and prevention or recurrences. Over the course of the HIV epidemic several new drugs and treatment approaches aimed at OIs have been introduced or refined. Guidelines have also been developed concerning the prevention of exposure to opportunistic pathogens.

Opportunistic infections affecting HIV-infected persons fall into four major categories:

  1. Parasitic/Protozoa infectionscryptosporidiosis, toxoplasmosis, isosporiasis, and microsporidiosis.
  2. Fungal infectionspneumocystosis, cryptococcus, candidiasis (thrush), histoplasmosis, and coccidioidomycosis.
  3. Bacterial infectionsmycobacterium avium complex (MAC), mycobacterium tuberculosis (TB), and salmanellosis.
  4. Viral infectionscytomegalovirus, herpes simplex types 1 and 2, and varicella-zoster virus (shingles), cytomegalovirus, and hepatitis.

Parasitic infections can cause significant illness and death among HIV-infected persons. Fungal diseases may vary widely among persons with HIV disease because many are commonly found in certain parts of the world and less common in others. Bacterial infections are also seen as important causes of illness and death in HIV-infected persons. Viral infections are common in this population and are often difficult to treat because of the limited number of antiviral drugs that are available. Persons with HIV disease often suffer from recurrences of viral infections. Those whose immune systems are severely compromised may have multiple infections simultaneously.

Two categories of malignancies that are often seen in persons with HIV disease are Kaposi's sarcoma (KS) and HIV-associated lymphomas. Prior to the HIV epidemic KS was rarely seen in the United States. Since the mid-1990s, researchers have also suggested an association between cervical and anal cancers. When cancers develop in a person with HIV disease these conditions tend to be aggressive and resistant to treatment.

In addition to the opportunistic infections and malignancies, persons with HIV disease may experience Wasting syndrome and changes in mental functioning. Wasting syndrome is a weight loss of at least 10 percent in the presence of diarrhea or chronic weakness and documented fever for at least thirty days that is not attributable to a concurrent condition other than HIV infection. Multiple factors are known to cause this weight loss and muscle wasting, including loss of appetite, decreased oral intake, and nausea and vomiting. Wasting is associated with rapid decline in overall health, increased risk of hospitalization, development of opportunistic infection, decreased quality of life, and decreased survival. Interventions include management of infections, oral nutritional supplements, use of appetite stimulants, management of diarrhea and fluid loss, and exercise.

AIDS dementia complex (ADC) is a complication of late HIV infection and the most common cause of neurological dysfunction in adults with HIV disease. Its cause is believed to be direct infection of the central nervous system by HIV. This condition can impair the intellect and alter motor performance and behavior. Early symptoms include difficulty in concentration, slowness in thinking and response, memory impairment, social withdrawal, apathy, personality changes, gait changes, difficulty with motor movements, and poor balance and coordination. As ADC advances, the affected person's cognitive functioning and motor skills worsen. Affected persons may enter a vegetative state requiring total care and environmental control. Treatment focuses on supportive care measures and aggressive use of HAART.

Finally, persons with HIV disease frequently experience mental disorders, especially anxiety and depression. These are typically treated by standard drug therapy and psychotherapy. Persons with HIV disease are also at greater risk of social isolation, which can have a negative impact on their mental and physical health.

Management of HIV Disease

Better understanding of HIV pathogenesis, better ways to measure HIV in the blood, and improved drug treatments have greatly improved the outlook for HIV-infected persons. Medical management focuses on the diagnosis, prevention, and treatment of HIV infection and related opportunistic infections and malignancies. HIV-infected persons who seek care from such providers should expect to receive compassionate and expert care in such settings. Management of HIV disease includes:

  • early detection of HIV infection;
  • early and regular expert medical evaluation of clinical status;
  • education to prevent further spread of HIV infection and to maintain a healthy lifestyle;
  • administration of antiretroviral drugs;
  • provision of drugs to prevent the emergence of specific opportunistic infections;
  • provision of emotional/social support;
  • medical management of HIV-related symptoms;
  • early diagnosis and appropriate management of OIs and malignancies; and
  • referral to medical specialists when indicated.

The mainstay of medical treatment for HIV-infected persons is the use of antiretroviral drugs. Goals of antiretroviral therapy are to prolong life and improve quality of life; to suppress virus below limit of detection for as long as possible; to optimize and extend usefulness of available therapies; and to minimize drug toxicity and manage side effects.

Two major classes of antiretroviral drugs are available for use in the treatment of HIV infectionreverse transcriptase inhibitors (RTIs) and protease inhibitors (PIs). These drugs act by inhibiting viral replication. RTIs interfere with reverse transcriptase, an enzyme essential in transcribing RNA into DNA in the HIV replication cycle. Protease inhibitor drugs work by inhibiting the HIV protease enzyme, thus preventing cleavage and release of mature, infectious viral particles. Dozens of other drugs that may become available in the next few years to treat HIV infection are under development and testing. Because of the high costs of these drugs, individuals needing assistance may gain access to HIV-related medications through the AIDS Drug Assistance Program (ADAP) and national pharmaceutical industry patient assistance/expanded access programs.

Panels of HIV disease experts have released guidelines for the use of antiretroviral agents in infected persons. The guidelines, which are revised periodically to reflect rapidly evolving knowledge relative to treatment, are widely available on the Internet. These guidelines have greatly assisted practitioners to provide a higher standard of care for persons living with HIV disease.

Viral load tests and CD4+ T-cell counts are used to guide antiretroviral drug treatment, which is usually initiated when the CD4+ T-cell count falls below 500 and/or there is evidence of symptomatic disease (e.g., AIDS, thrush, unexplained fever). Some clinicians recommend antiretroviral drug treatment to asymptomatic HIV-infected persons.

Because HIV replicates and mutates rapidly, drug-resistance is a challenge, forcing clinicians to alter drug regimens when these instances occur. Inadequate treatment, poor adherence, and interruptions in treatment increase drug resistance. This resistance can be delayed by the use of combination regimens to achieve CD4+ T-cell counts below the level of detection. Careful adherence to prescribed HAART regimens is crucial in treatment and many interventions have been tried to improve patient adherence. Because some HIV-infected persons are taking multiple doses of multiple drugs daily, adherence challenges patients and clinicians alike. Once antiretroviral therapy has been initiated patients remain on this therapy continuously, although intermittent drug treatment is being studied. Because persons living with HIV disease may take numerous drugs simultaneously, the potential for drug interactions and adverse reactions is high. These persons typically have a higher incidence of adverse reactions to commonly used drugs than do non-HIV-infected patients.

In the United States HIV/AIDS is an epidemic primarily affecting men who have sex with men and ethnic/racial minorities. Homophobia, poverty, homelessness, racism, lack of education, and lack of access to health care greatly influence testing, treatment, and prevention strategies. While an effective vaccine is crucial to the prevention of HIV, efforts to develop such a vaccine have been unsuccessful to date; therefore, current and future prevention efforts, including behavior modification interventions, must be aimed at ethnic minorities, men who have sex with men, and other high-risk populations. Finally, a safe, effective antiviral product that women can use during sexual intercourse would greatly reduce their risk of infection.

See also: Causes of Death; Pain and Pain Management; Suicide Influences and Factors: Physical Illness; Symptoms and Symptom Management

Bibliography

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Berger, Barbara, and Vida M. Vizgirda. "Preventing HIV Infection." In Jerry Durham and Felissa Lashley eds., The Person with HIV/AIDS: Nursing Perspectives. New York: Springer, 2000.

Centers for Disease Control and Prevention. HIV/AIDS Surveillance Supplemental Report, 2000. Rockville, MD: Author, 2001.

Centers for Disease Control and Prevention. "HIV/AIDSUnited States, 19812000." Morbidity and Mortality Weekly Report 50 (2001):430434.

Cohen, Philip T., and Mitchell H. Katz. "Long-Term Primary Care Management of HIV Disease." In Philip T. Cohen, Merle A. Sande, and Paul Volberding, et al. eds, The AIDS Knowledge Base: A Textbook on HIV Disease from the University of California, San Francisco and San Francisco General Hospital. New York: Lippincott Williams & Wilkins, 1999.

Coleman, Rebecca, and Christopher Holtzer. "HIV-Related Drug Information." In Philip T. Cohen, Merle A. Sande, and Paul Volberding, et al. eds., The AIDS Knowledge Base: A Textbook on HIV Disease from the University of California, San Francisco and San Francisco General Hospital. New York: Lippincott Williams & Wilkins, 1999.

Corless, Inge. "HIV/AIDS." In Felissa Lashley and Jerry Durham eds., Emerging Infectious Diseases. New York: Springer, 2002.

Deeks, Steven, and Paul Volberding. "Antiretroviral Therapy for HIV Disease." In Philip T. Cohen, Merle A. Sande, and Paul Volberding, et al. eds., The AIDS Knowledge Base: A Textbook on HIV Disease from the University of California, San Francisco and San Francisco General Hospital. New York: Lippincott Williams & Wilkins, 1999.

Erlen, Judith A., and Mary P. Mellors. "Adherence to Combination Therapy in Persons Living with HIV: Balancing the Hardships and the Blessings." Journal of the Association of Nurses in AIDS Care 10, no. 4 (1999):7584.

Ferri, Richard. "Testing and Counseling." In Jerry Durham and Felissa Lashley eds., The Person with HIV/AIDS: Nursing Perspectives. New York: Springer, 2000.

Horton, Richard. "New Data Challenge OPV Theory of AIDS Origin." Lancet 356 (2000):1005.

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Lamptey, Peter R. "Reducing Heterosexual Transmission of HIV in Poor Countries." British Medical Journal 324 (2002):207211.

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Lashley, Felissa. "The Etiology, Epidemiology, Transmission, and Natural History of HIV Infection and AIDS." In Jerry Durham and Felissa Lashley eds., The Person with HIV/AIDS: Nursing Perspectives. New York: Springer, 2000.

Osmond, Dennis H. "Classification, Staging, and Surveillance of HIV Disease." In P. T. Cohen, Merle A. Sande, and Paul Volberding, et al. eds, The AIDS Knowledge Base: A Textbook on HIV Disease from the University of California, San Francisco and San Francisco General Hospital. New York: Lippincott Williams & Wilkins, 1999.

Wightman, Susan, and Michael Klebert. "The Medical Treatment of HIV Disease." In Jerry Durham and Felissa Lashley eds., The Person with HIV/AIDS: Nursing Perspectives. New York: Springer, 2000.

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Centers for Disease Control and Prevention (CDC). "Revised Guidelines for HIV Counseling, Testing, and Referral." In the CDC [web site]. Available from www.cdc.gov/hiv/ctr/default.htm.

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UNAIDS. "AIDS Epidemic UpdateDecember 2001." In the UNAIDS [web site]. Available from www.unaids.org/epidemic_update/report_dec01/index.html.

United States Census Bureau. "HIV/AIDS Surveillance." In the U.S. Census Bureau [web site]. Available from www.census.gov/ipc/www/hivaidsn.html.

JERRY D. DURHAM

views updated

AIDS

Definition

Acquired immune deficiency syndrome (AIDS) is an infectious disease caused by the human immunodeficiency virus (HIV). It was first recognized in the United States in 1981. AIDS is the advanced form of infection with the HIV virus, which may not cause disease for a long period after the initial exposure (latency). Infection with HIV weakens the immune system which makes infected people susceptible to infection and cancer .

Description

AIDS is considered one of the most devastating public health problems in recent history. In 1996, the Centers for Disease Control and Prevention (CDC) estimated that one million persons in the United States were HIV-positive, and 223,000 are living with AIDS. Of these patients, 44% were gay or bisexual men, 26% are heterosexual intravenous drug users, and 18% were women. In addition, approximately 1,000-2,000 children are born each year with HIV infection. In 2002, the CDC reported 42,136 new AIDS diagnoses in the United States, a 2.2% increase from the previous year. AIDS cases rose among gay and bisexual men (7.1% in 25 states that report regularly). The disease also seems to be rising among older Americans. From 1990 to 2001, the number of cases in Americans age 50 years or older rose from 16,288 to 90,153.

The World Health Organization (WHO) estimates that 40 million people worldwide were infected with AIDS/HIV as of 2001. Most of these cases are in the developing countries of Asia and Africa. In 2003, WHO cautioned that if treatment were not delivered soon to nearly 6 million people with AIDS in developing countries, there could be 45 million cases by 2010.

Risk factors

AIDS can be transmitted in several ways. The risk factors for HIV transmission vary according to category:

  • Sexual contact. Persons at greatest risk are those who do not practice safe sex, are not monogamous, participate in anal intercourse, and have sex with a partner with symptoms of advanced HIV infection and/or other sexually transmitted diseases (STDs). In the United States and Europe, most cases of sexually transmitted HIV infection have resulted from homosexual contact, whereas in Africa, the disease is spread primarily through sexual intercourse among heterosexuals.
  • Transmission in pregnancy . High-risk mothers include women married to bisexual men or men who have an abnormal blood condition called hemophilia and require blood transfusions, intravenous drug users, and women living in neighborhoods with a high rate of HIV infection among heterosexuals. The chances of transmitting the disease to the child are higher in women in advanced stages of the disease. Breast feeding increases the risk of transmission by 10-20% and is not recommended. The use of zidovudine (AZT) during pregnancy and delivery, however, can decrease the risk of transmission to the baby.
  • Exposure to contaminated blood or blood products. With the introduction of blood product screening in the mid-1980s, the incidence of HIV transmission in blood transfusions has dropped to 1 in 100,000.
  • Needle sticks among health care professionals. Present studies indicate that the risk of HIV transmission by a needle stick is about 1 in 250. This rate can be decreased if the injured worker is given AZT or triple therapy (HAART), the current standard.

HIV is not transmitted by handshakes or other casual non-sexual contact, coughing or sneezing , or by bloodsucking insects such as mosquitoes.

AIDS in women

AIDS in women is a serious public health concern. Women exposed to HIV infection through heterosexual contact are the most rapidly growing risk group in the United States. The percentage of AIDS cases diagnosed in women has risen from 7% in 1985 to 18% in 1996. For unknown reasons, women with AIDS do not live as long as men with AIDS.

AIDS in children

Because AIDS can be transmitted from an infected mother to her child during pregnancy, during the birth process, or through breast milk, all infants born to HIV-positive

mothers are at risk. As of 1997, it was estimated that 84% of HIV-positive women are of childbearing age; 41% of them are drug abusers. Between 15-30% of children born to HIV-positive women will be infected with the virus.

AIDS is one of the 10 leading causes of death in children between one and four years of age worldwide. The interval between exposure to HIV and the development of AIDS is shorter in children than in adults. Infants infected with HIV have a 20-30% chance of developing AIDS within a year and dying before age three. In the remainder, AIDS progresses more slowly; the average child patient survives to seven years of age. Some survive into early adolescence.

Causes & symptoms

Because HIV destroys immune system cells, AIDS is a disease that can affect any of the body's major organ systems. HIV attacks the body through three disease processes: immunodeficiency, autoimmunity, and nervous system dysfunction.

Immunodeficiency describes the condition in which the body's immune response is damaged, weakened, or is not functioning properly. In AIDS, immunodeficiency results from the way that the virus binds to a protein called CD4, which is found on certain white blood cells, including helper T cells, macrophages, and monocytes. Once HIV attaches to an immune system cell, it can replicate within the cell and kill the cell. In addition to killing some lymphocytes directly, the AIDS virus disrupts the functioning of other CD4 cells. Because the immune system cells are destroyed, infections and cancers that take advantage of a person's weakened immune system (opportunistic) can develop.

Autoimmunity is a condition in which the body's immune system produces antibodies that work against its own cells. Antibodies are specific proteins produced in response to exposure to a specific, usually foreign, protein or particle called an antigen. In this case, the body produces antibodies that bind to blood platelets that are necessary for proper blood clotting and tissue repair. Once bound, the antibodies mark the platelets for removal from the body, and they are filtered out by the spleen. Some AIDS patients develop a disorder, called immune-related thrombocytopenia purpura (ITP), in which the number of blood platelets drops to abnormally low levels.

The course of AIDS generally progresses through three stages, although not all patients will follow this progression precisely:

Acute retroviral syndrome

Acute retroviral syndrome is a term used to describe a group of symptoms that can resemble mononucleosis and that may be the first sign of HIV infection in 50-70% of all patients and 45-90% of women. The symptoms may include fever, fatigue , muscle aches, loss of appetite, digestive disturbances, weight loss, skin rashes, headache , and chronically swollen lymph nodes (lymphadenopathy). Approximately 25-33% of patients will experience a form of meningitis during this phase, in which the membranes that cover the brain and spinal cord become inflamed. Acute retroviral syndrome develops between one and six weeks after infection and lasts two to four weeks, sometimes up to six weeks. Blood tests during this period will indicate the presence of virus (viremia) and the appearance of the viral p24 antigen in the blood.

Latency period

After the HIV virus enters a patient's lymph nodes during the acute retroviral syndrome stage, the disease becomes latent for as many as 10 years or more before symptoms of advanced disease develop. During latency, the virus continues to replicate in the lymph nodes, where it may cause one or more of the following conditions.

PERSISTENT GENERALIZED LYMPHADENOPATHY (PGL). Persistent generalized lymphadenopathy, or PGL, is a condition in which HIV continues to produce chronic painless swellings in the lymph nodes during the latency period. The lymph nodes most frequently affected by PGL are those in the areas of the neck, jaw, groin, and armpits. PGL affects between 50-70% of patients during latency.

CONSTITUTIONAL SYMPTOMS. Many patients will develop low-grade fevers, chronic fatigue, and general weakness. HIV also may cause a combination of food malabsorption, loss of appetite, and increased metabolism that contribute to the so-called AIDS wasting or wasting syndrome.

OTHER ORGAN SYSTEMS. At any time during the course of HIV infection, patients may suffer from a yeast infection in the mouth called thrush, open sores or ulcers, or other infections of the mouth; diarrhea and other gastrointestinal symptoms that cause malnutrition and weight loss; diseases of the lungs and kidneys; and degeneration of the nerve fibers in the arms and legs. HIV infection of the nervous system leads to general loss of strength, loss of reflexes, and feelings of numbness or burning sensations in the feet or lower legs.

Late-stage AIDS

Late-stage AIDS usually is marked by a sharp decline in the number of CD4+ lymphocytes (a type of white blood cell), followed by a rise in the frequency of opportunistic infections and cancers. Doctors monitor the number and proportion of CD4+ lymphocytes in the patient's blood in order to assess the progression of the disease and the effectiveness of different medications. About 10% of infected individuals never progress to this overt stage of the disease.

OPPORTUNISTIC INFECTIONS. Once the patient's CD4+ lymphocyte count falls below 200 cells/mm3, he or she is at risk for opportunistic infections. The infectious organisms may include:

  • Fungi. Fungal infections include a yeast infection of the mouth (candidiasis or thrush) and cryptococcal meningitis.
  • Protozoa. The most common parasitic disease associated with AIDS is Pneumocystis carinii pneumonia (PCP). About 70-80% of AIDS patients will have at least one episode of PCP prior to death. PCP is the immediate cause of death in 15-20% of AIDS patients. It is an important measure of a patient's prognosis. Toxoplasmosis is another common infection in AIDS patients that is caused by a protozoan. Other diseases in this category include amebiasis and cryptosporidiosis.
  • Mycobacteria. AIDS patients may develop tuberculosis or MAC infections. MAC infections are caused by Mycobacterium avium-intracellulare, and occur in about 40% of AIDS patients.
  • Bacteria. AIDS patients are likely to develop bacterial infections of the skin and digestive tract.
  • Viruses. AIDS patients are highly vulnerable to cytomegalovirus (CMV), herpes simplex virus (HSV), varicella zoster virus (VZV), and Epstein-Barr virus (EBV) infections. Another virus, JC virus, causes progressive destruction of brain tissue in the brain stem, cerebrum, and cerebellum (multifocal leukoencephalopathy or PML), which is regarded as an AIDS-defining illness by the Centers for Disease Control and Prevention.
ESTIMATED NUMBER OF ADULTS AND CHILDREN LIVING WITH AIDS/HIV WORLDWIDE AS OF 2001
Regions Estimate
Australia & New Zealand 15,000
Caribbean 420,000
East Asia & Pacific 1,000,000
Eastern Europe & Central Asia 1,000,000
Latin America 1,500,000
North Africa & Middle East 500,000
North America 950,000
South & Southeast Asia 5,600,000
Sub-Saharan African 28,500,000
Western Europe 550,000
Global total 40,000,000+

AIDS DEMENTIA COMPLEX AND NEUROLOGIC COMPLICATIONS. AIDS dementia complex is a late complication of the disease. It is unclear whether it is caused by the direct effects of the virus on the brain or by intermediate causes. AIDS dementia complex is marked by loss of reasoning ability, loss of memory, inability to concentrate, apathy and loss of initiative, and unsteadiness or weakness in walking. Some patients also develop seizures.

MUSCULOSKELETAL COMPLICATIONS. Patients in late-stage AIDS may develop inflammations of the muscles, particularly in the hip area, and may have arthritis-like pains in the joints.

ORAL SYMPTOMS. Patients may develop a condition called hairy leukoplakia of the tongue. This condition also is regarded by the CDC as an indicator of AIDS. Hairy leukoplakia is a white area of diseased tissue on the tongue that may be flat or slightly raised. It is caused by the Epstein-Barr virus.

AIDS-RELATED CANCERS. Patients with late-stage AIDS may develop Kaposi's sarcoma (KS), a skin tumor that primarily affects homosexual men. KS is the most common AIDS-related malignancy. It is characterized by reddish-purple blotches or patches (brownish in African-Americans) on the skin or in the mouth. About 40% of patients with KS develop symptoms in the digestive tract or lungs. KS appears to be caused by a herpes virus.

The second most common form of cancer in AIDS patients is a tumor of the lymphatic system (lymphoma). AIDS-related lymphomas often affect the central nervous system and develop very aggressively.

Invasive cancer of the cervix is an important diagnostic marker of AIDS in women.

Diagnosis

Because HIV infection produces such a wide range of symptoms, the CDC has drawn up a list of 34 conditions regarded as defining AIDS. The physician will use the CDC list to decide whether the patient falls into one of these three groups:

  • definitive diagnoses with or without laboratory evidence of HIV infection
  • definitive diagnoses with laboratory evidence of HIV infection
  • presumptive diagnoses with laboratory evidence of HIV infection

Physical findings

Almost all symptoms of AIDS can occur with other diseases. The general physical examination may range from normal findings to symptoms that are closely associated with AIDS. These symptoms are hairy leukoplakia of the tongue and Kaposi's sarcoma. When the doctor examines the patient, he or she will look for the overall pattern of symptoms rather than any one finding.

Laboratory tests for HIV infection

BLOOD TESTS (SEROLOGY). The first blood test for AIDS was developed in 1985. At present, patients who are being tested for HIV infection usually are given an enzyme-linked immunosorbent assay (ELISA) test for the presence of HIV antibody in their blood. Positive ELISA results then are tested with a Western blot or immunofluorescence (IFA) assay for confirmation. The combination of the ELISA and Western blot tests is more than 99.9% accurate in detecting HIV infection within four to eight weeks following exposure. The polymerase chain reaction (PCR) test can be used to detect the presence of viral nucleic acids in the very small number of HIV patients who have false-negative results on the ELISA and Western blot tests. In 2003, a one-step test that was quicker and cheaper was shown effective for detecting HIV in the physician office setting. However, further research was ongoing as to its effectiveness in replacing current tests as a first check for HIV.

OTHER LABORATORY TESTS. In addition to diagnostic blood tests, there are other blood tests that are used to track the course of AIDS. These include blood counts, viral load tests, p24 antigen assays, and measurements of β2-microglobulin (β2M).

Doctors will use a wide variety of tests to diagnose the presence of opportunistic infections, cancers, or other disease conditions in AIDS patients. Tissue biopsies, samples of cerebrospinal fluid, and sophisticated imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography scans (CT) are used to diagnose AIDS-related cancers, some opportunistic infections, damage to the central nervous system, and wasting of the muscles. Urine and stool samples are used to diagnose infections caused by parasites. AIDS patients also are given blood tests for syphilis and other sexually transmitted diseases.

Diagnosis in children

Diagnostic blood testing in children older than 18 months is similar to adult testing, with ELISA screening confirmed by Western blot. Younger infants can be diagnosed by direct culture of the HIV virus, PCR testing, and p24 antigen testing.

In terms of symptoms, children are less likely than adults to have an early acute syndrome. They are, however, likely to have delayed growth, a history of frequent illness, recurrent ear infections, a low blood cell count, failure to gain weight, and unexplained fevers. Children with AIDS are more likely to develop bacterial infections, inflammation of the lungs, and AIDS-related brain disorders than are HIV-positive adults.

Treatment

AIDS patients turn to alternative medicine when conventional treatments are ineffective, and to supplement conventional treatment, reduce disease symptoms, counteract drug effects, and improve quality of life. Because alternative medicines may interact with conventional medicines, it is important for the patient to inform his or her doctor of all treatments being used.

A report released in 2003 showed trends in increased use of alternative medicine among HIV-positive individuals. Based on 1997 figures, the study reported that 79% of those seeking alternative therapy to help with AIDS treatment or symptom relief were men and 63% were women. The types of therapies they used most were relaxation techniques, massage, chiropractic care, self-help groups, commercial diets , and acupuncture .

Supplements

  • Lauric oils (coconut oil) are used by the body to make monolaurin, which inactivates HIV.
  • Selenium deficiency increases the risk of death due to AIDS-related illness. One study found that 250 micrograms of selenomethionin daily for one year showed no improvement in CD4 cell counts or disease symptoms. Greater than 1,000 micrograms daily is toxic.
  • Vitamin C has antioxidant and antiretroviral activities. One study found that treatment caused a trend to decrease viral load.
  • DHEA (dehydroepiandrosterone) is commonly used by AIDS patients to counteract wasting. One study found that DHEA had no effect on lymphocytes or p24 antigen levels. However, a 2002 study found that it was associated with a significant increase in measures that indicate mental health improvement.
  • Vitamin A deficiency is associated with increased mortality. One study of pregnant women with AIDS found that 5000 IU of vitamin A daily led to stabilized viral load as compared to a placebo group. Another study found that 60 mg of vitamin A had no effect on CD4 cells or viral load. Vitamin A has been associated with faster disease progression. Excessive vitamin A during pregnancy can cause birth defects.
  • Beta-carotene supplementation for AIDS is controversial as studies have shown both beneficial and detrimental effects. Beta-carotene supplementation has led to elevation in white blood cell counts and changes in the CD4 cell count. Some studies have found that beta-carotene supplementation led to an increase in deaths due to cancer and heart disease .

Naturopathic doctors often recommend the following supplements for AIDS:

  • beta-carotene, 150,000 IU daily
  • vitamin C, 2,000 mg thrice daily
  • vitamin E, 400 IU twice daily
  • cod liver oil, 1 tablespoon daily
  • multivitamin, as directed
  • coenzyme Q 10, 50-60 mg twice daily

Herbals and Chinese medicine

One small study of the effectiveness of Chinese herbal treatment in AIDS showed promise. AIDS patients took a tablet that contained 31 herbs that was based on the formulas Enhance and Clear Heat. Disease symptoms were reduced in the herbal treatment group as compared to the placebo group.

Herbals used in treating AIDS include:

  • Maitake mushroom extract. Recommended dose is 10 drops twice daily
  • Licorice (Glycyrrhiza glabra ) solid extract. Recommended dose is one quarter to one half teaspoon twice daily
  • Boxwood extract (SPV-30) has antiviral activity. Recommended dose is one capsule thrice daily.
  • Garlic concentrate (Allicin) helped reduce bowel movements, stabilized or increased body weight, or cured Cryptosporidium parvum infection in affected AIDS patients. However, a 2002 National Institutes of Health study cautioned that garlic supplements could reduce levels of a protease inhibitor that is used to treat AIDS patients, so patients should discuss using garlic supplements with their physicians.
  • Tea tree oil (Malaleuca ) improves or cures infection of the mouth by the yeast Candida. Tea tree oil is available as soap, dental floss, toothpick, and mouthwash.
  • Marijuana is used to treat wasting. Studies have found that patients who use marijuana had increased food intake and weight gain. The active ingredient delta-9-tetrahydrocannabinol is licensed for treating AIDS wasting.

Psychotherapy and stress reduction

Many therapies that are directed at improving mental state can have a direct impact on disease severity and quality of life. The effectiveness of many have been proven in clinical studies. These include:

  • massage
  • laughter/humor
  • stress management training
  • visualization
  • cognitive therapy
  • aerobic exercise
  • prayer

Other treatments for AIDS include homeopathy , naturopathy, acupuncture, and chiropractic.

Allopathic treatment

Treatment for AIDS covers four categories:

Antiretroviral treatment

In recent years researchers have developed drugs that suppress HIV replication. The drugs are used in combination with one another and fall into four classes:

  • Nucleoside reverse transcriptase inhibitors. These drugs work by interfering with the action of HIV reverse transcriptase, thus ending the virus replication process. These drugs include zidovudine (sometimes called Zidovudine or AZT, trade name Retrovir), didanosine (ddi, Videx), emtricitabine (FTC, Emtriva), zalcitabine (ddC, Hivid), stavudine (d4T, Zerit), abacavir (Ziagen), tenofovir (df, Viread), and lamivudine (3TC, Epivir).
  • Protease inhibitors. Protease inhibitors are effective against HIV strains that have developed resistance to nucleoside analogues, and often are used in combination with them. These compounds include saquinavir (Fortovase), ritonavir (Norvir), indinavir (Crixivan), amprenavir (Agenerase), lopinavir plus ritonavir (Reyataz), and nelfinavir (Viracept).
  • Non-nucleoside reverse transcriptase inhibitors. This is a newer class of antiretroviral agents. Three are available, nevirapine (Viramune), efavirenz (Sustiva), and delavirdine (Rescriptor).
  • Fusion inhibitors. These drugs are less common, expensive and difficult to use. They block infection early by preventing HIV from fusing with and entering a human cell. This class includes only one compound: Enfuvirtide (Fuzeon).

Treatment guidelines for these agents are in constant change as new medications are developed and introduced. In mid-2003, the U.S. Department of Health and Human Services revised its guidelines for the use of these agents to help clinicians better choose the best combinations. The new guidelines offer a list of suggested combination regimens classified as either "preferred" or "alternative".

Treatment of opportunistic infections and malignancies

Most AIDS patients require complex long-term treatment with medications for infectious diseases. This treatment often is complicated by the development of resistance in the disease organisms. AIDS-related malignancies in the central nervous system usually are treated with radiation therapy. Cancers elsewhere in the body are treated with chemotherapy.

Prophylactic treatment for opportunistic infections

Prophylactic treatment is treatment that is given to prevent disease. AIDS patients with a history of Pneumocystis pneumonia; with CD4+ counts below 200 cells/mm3 or 14% of lymphocytes; weight loss; or thrush should be given prophylactic medications. The three drugs given are trimethoprim-sulfamethoxazole, dapsone, or pentamidine in aerosol form.

STIMULATION OF BLOOD CELL PRODUCTION. Because many patients with AIDS suffer from abnormally low levels of both red and white blood cells, they may be given medications to stimulate blood cell production. Epoetin alfa (erythropoietin) may be given to anemic patients. Patients with low white blood cell counts may be given filgrastim or sargramostim.

Treatment in women

Treatment of pregnant women with HIV is particularly important because antiretroviral therapy has been shown to reduce transmission to the infant by 65%.

Expected results

At the present time, there is no cure for AIDS. Treatment stresses aggressive combination drug therapy when possible. The use of multi-drug therapies has significantly reduced the number of U.S. deaths resulting from AIDS. The potential exists to possibly prolong life indefinitely using these and other drug therapies to boost the immune system, keep the virus from replicating, and ward off opportunistic infections and malignancies.

Prognosis after the latency period depends on the patient's specific symptoms and the organ systems affected by the disease. Patients with AIDS-related lymphomas of the central nervous system die within two to three months of diagnosis; those with systemic lymphomas may survive for eight to ten months. In America, the successful treatment of AIDS patients with HAART has actually led to a growing number of people living with HIV. About 25,000 infected people per year are added to the list of HIV-infected Americans.

However, not only does HAART and other treatment prolong AIDS patients' lives, it has led to some improvement in quality of life too. A recent study shows that HAART therapy substantially reduces risk of AIDS-related pneumonia (PCP), although PCP still remains the most common AIDS-defining illness among opportunistic infections. Other recent studies show that these protease inhibitors may result in high cholesterol and put AIDS patients at eventual risk for heart disease. Further research must be done, since long-term effects of HAART treatment are just now being studied. Most clinicians would say the benefits outweigh the risks anyway.

Prevention

As of 2000, there is no vaccine effective against AIDS. Several vaccines to prevent initial HIV infection and disease progression are being tested. In 2002, reports showed a new "library" vaccine showed potential. The vaccine is composed of up to 32 HIV gene fragments that can induce a number of immune responses. In the same year, the British government worked with five African countries in a trial to find an effective gel that would protect women against HIV during sex. The study leaders believed if they could find a lotion that could be applied before intercourse that would help prevent HIV transmission, they would give women the ability to better protect themselves from HIV. In 2003, the first human test of a vaccine against the most common subtype of HIV was underway.

Precautions to take to prevent the spread of AIDS include:

  • Monogamy and practicing safe sex. Besides avoiding the risk of HIV infection, condoms are successful in preventing other sexually transmitted diseases and unwanted pregnancies.
  • Avoiding needle sharing among intravenous drug users.
  • Although blood and blood products are carefully monitored, those individuals who are planning to undergo major surgery may wish to donate blood ahead of time to prevent a risk of infection from a blood transfusion.
  • Healthcare professionals should wear gloves and masks when handling body fluids and avoid needle-stick injuries.
  • A person who suspects that he or she may have become infected should get tested. If treated aggressively and early, the development of AIDS can sometimes be postponed indefinitely. If HIV infection is confirmed, it also is vital to inform sexual partners.

Resources

BOOKS

Abrams, Donald I. "Alternative Therapies." AIDS Therapy. edited by Raphael Dolin et al. Philadelphia: Churchill Livingstone, 1999.

Early HIV Infection Guideline Panel. Evaluation and Management of Early HIV Infection. Rockville, MD: U.S. Department of Health and Human Services, Agency for Health Care Policy and Research, 1994.

The Global AIDS Policy Coalition. AIDS in the World. Cambridge, MA: Harvard University Press, 1992.

Huber, Jeffrey T. Dictionary of AIDS-Related Terminology. New York and London: Neal-Schuman Publishers, Inc., 1993.

"Infectious Diseases: Human Immunodeficiency Virus (HIV)." In Neonatology: Management, Procedures, On-Call Problems, Diseases and Drugs. edited by Tricia Lacy Gomella, et al. Norwalk, CT: Appleton & Lange, 1994.

Katz, Mitchell H. and Harry Hollander. "HIV Infection." In Current Medical Diagnosis & Treatment 1998. edited by Lawrence M. Tierney Jr., et al. Stamford, CT: Appleton & Lange, 1998.

McCutchan, J. Allen. "Alternative, Unconventional, and Unproven Therapies." Textbook of AIDS Medicine, 2nd edition. edited by Thomas C. Merigan, et al. Baltimore: Williams & Wilkins, 1999.

McFarland, Elizabeth J. "Human Immunodeficiency Virus (HIV) Infections: Acquired Immunodeficiency Syndrome (AIDS)." In Current Pediatric Diagnosis & Treatment. edited by William W. Hay Jr., et al. Stamford, CT: Appleton & Lange, 1997.

So, Peter and Livette Johnson. "Acquired Immune Deficiency Syndrome (AIDS)." In Conn's Current Therapy. edited by Robert E. Rakel. Philadelphia: W. B. Saunders Company, 1997.

Standish, Leanna J., Roberta C.M. Wines, and Cherie Reeves. "Complementary/Alternative Therapies in Select Populations: Women with HIV and AIDS." In Complementary/Alternative Medicine: An Evidence Based Approach. edited by John W. Spencer and Joseph J. Jacobs. St. Louis: Mosby, 1999.

PERIODICALS

"DHEA in HIV Infection." Infectious Disease Alert. (March 1, 2002): S7.

Ernst, Jerome. "Alternative Treatment Modalities in Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome." Clinical Infectious Diseases (September 1, 2003): 150154.

"First Human Tests Under Way of HIV Vaccine Pioneered at UNC." AIDS Vaccine Week (August 25, 2003): 2.

Fleck, Fiona. "British Medical Journal." British Medical Journal (September 27, 2003): 698.

Gangel, Elaine K. "Garlic Supplements and HIV Medication." American Family Physician (March 15, 2002): 1225.

"Government Lauches Trial of Gel to Protect Women Against HIV." AIDS Weekly (March 25, 2002): 11.

"HIV Drugs Approved as of August 2003." AIDS Treatment News (July 25, 2003): 4.

"HIV Rising Among Gay, Bisexual Men." Medical Letter on the CDC & FDA (August 24, 2003): 9.

"Is HAART Hard on the Heart" Science News (March 9, 2002): 158.

"Library Vaccine Shows Promise." Vaccine Weekly. (February 13, 2002): 2.

"One-step HIV Test May Be Cheaper, Faster, Less Wasteful." AIDS Weekly (September 29, 2003): 13.

Ozsoy, Metin and Edzard Ernst. "How Effective are Complementary Therapies for HIV and AIDS?a Systematic Review." International Journal of STD & AIDS 10 (1999): 629-635.

"Prevalence of HIV Infection Increasing in Older Americans." AIDS Weekly (September 1, 2003): 16.

"Revised Guidelines Will Ease Selection of HIV/AIDS Treatments." Drug Week (August 8, 2003): 10.

"Successful HAART Reduces Risk of Pneumonia." AIDS Weekly (January 14, 2002): 24.

"Success of Treatment Swells Ranks of HIV Infected." AIDS Weekly (March 25, 2002): 13.

Wootton, Jacqueline C. "WebWatch: Alternative and Complementary Therapies." AIDS Patient Care and STDs 12 (1998): 811-813.

ORGANIZATIONS

American Foundation for AIDS Research, 733 Third Avenue, 12th floor, 1515 Broadway, Suite 3601, New York, NY 10017. (212) 682-7440.

Gay Men's Health Crisis, Inc., 129 West 20th Street, New York, NY 10011-0022. (212) 807-6655.

National AIDS Hot Line. (800) 342-AIDS (English). (800) 344-SIDA (Spanish). (800) AIDS-TTY (hearing-impaired).

Belinda Rowland

Teresa G. Odle

views updated

AIDS Tests

Definition

AIDS tests, short for acquired immunodeficiency syndrome tests, cover a number of different procedures used in the diagnosis and treatment of HIV patients. These tests sometimes are called AIDS serology tests. Serology is the branch of immunology that deals with the contents and characteristics of blood serum. Serum is the clear light yellow part of blood that remains liquid when blood cells form a clot. AIDS serology evaluates the presence of human immunodeficiency virus (HIV) infection in blood serum and its effects on each patient's immune system.

Purpose

AIDS serology serves several different purposes. Some AIDS tests are used to diagnose patients or confirm a diagnosis; others are used to measure the progression of the disease or the effectiveness of specific treatment regimens. Some AIDS tests also can be used to screen blood donations for safe use in transfusions.

In order to understand the different purposes of the blood tests used with AIDS patients, it is helpful to understand how HIV infection affects human blood and the immune system. HIV is a retrovirus that enters the blood stream of a new host in the following ways:

  • by sexual contact
  • by contact with infected body fluids (such as blood and urine)
  • by transmission during pregnancy, or
  • through transfusion of infected blood products

A retrovirus is a virus that contains a unique enzyme called reverse transcriptase that allows it to replicate within new host cells. The virus binds to a protein called CD4, which is found on the surface of certain subtypes of white blood cells, including helper T cells, macrophages, and monocytes. Once HIV enters the cell, it can replicate and kill the cell in ways that are still not completely understood. In addition to killing some lymphocytes directly, the AIDS virus disrupts the functioning of the remaining CD4 cells. CD4 cells ordinarily produce a substance called interleukin-2 (IL-2), which stimulates other cells (T cells and B cells) in the human immune system to respond to infections. Without the IL-2, T cells do not reproduce as they normally would in response to the HIV virus, and B cells are not stimulated to respond to the infection.

Precautions

In some states such as New York, a signed consent form is needed in order to administer an AIDS test. As with all blood tests, healthcare professionals should always wear latex gloves and avoid being pricked by the needle used in drawing blood for the tests. It may be difficult to get blood from a habitual intravenous drug user due to collapsed veins.

Description

Diagnostic tests

Diagnostic blood tests for AIDS usually are given to persons in high-risk populations who may have been exposed to HIV or who have the early symptoms of AIDS. Most persons infected with HIV will develop a detectable level of antibody within three months of infection. The condition of testing positive for HIV antibody in the blood is called seroconversion, and persons who have become HIV-positive are called seroconverters.

It is possible to diagnose HIV infection by isolating the virus itself from a blood sample or by demonstrating the presence of HIV antigen in the blood. Viral culture, however, is expensive, not widely available, and slowit takes 28 days to complete the viral culture test. More common are blood tests that work by detecting the presence of antibodies to the HIV virus. These tests are inexpensive, widely available, and accurate in detecting 99.9% of AIDS infections when used in combination to screen patients and confirm diagnoses.

ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA). This type of blood test is used to screen blood for transfusions as well as diagnose patients. An ELISA test for HIV works by attaching HIV antigens to a plastic well or beads. A sample of the patient's blood serum is added, and excess proteins are removed. A second antibody coupled to an enzyme is added, followed by addition of a substance that will cause the enzyme to react by forming a color. An instrument called a spectrophotometer can measure the color. The name of the test is derived from the use of the enzyme that is coupled or linked to the second antibody.

KEY TERMS

Antibody A protein in the blood that identifies and helps remove disease organisms or their toxins. Antibodies are secreted by B cells. AIDS diagnostic tests work by demonstrating the presence of HIV antibody in the patient's blood.

Antigen Any substance that stimulates the body to produce antibodies.

B cell A type of white blood cell derived from bone marrow. B cells are sometimes called B lymphocytes. They secrete antibody and have a number of other complex functions within the human immune system.

CD4 A type of protein molecule in human blood that is present on the surface of 65% of human T cells. CD4 is a receptor for the HIV virus. When the HIV virus infects cells with CD4 surface proteins, it depletes the number of T cells, B cells, natural killer cells, and monocytes in the patient's blood. Most of the damage to an AIDS patient's immune system is done by the virus' destruction of CD4+ lymphocytes. CD4 is sometimes called the T4 antigen.

Complete blood count (CBC) A routine analysis performed on a sample of blood taken from the patient's vein with a needle and vacuum tube. The measurements taken in a CBC include a white blood cell count, a red blood cell count, the red cell distribution width, the hematocrit (ratio of the volume of the red blood cells to the blood volume), and the amount of hemoglobin (the blood protein that carries oxygen). CBCs are a routine blood test used for many medical reasons, not only for AIDS patients. They can help the doctor determine if a patient is in advanced stages of the disease.

Electrophoresis A method of separating complex protein molecules suspended in a gel by running an electric current through the gel.

Enzyme-linked immunosorbent assay (ELISA) A diagnostic blood test used to screen patients for AIDS or other viruses. The patient's blood is mixed with antigen attached to a plastic tube or bead surface. A sample of the patient's blood serum is added, and excess proteins are removed. A second antibody coupled to an enzyme is added, followed by a chemical that will cause a color reaction that can be measured by a special instrument.

Human immunodeficiency virus (HIV) A transmissible retrovirus that causes AIDS in humans. Two forms of HIV are now recognized: HIV-1, which causes most cases of AIDS in Europe, North and South America, and most parts of Africa; and HIV-2, which is chiefly found in West African patients. HIV-2, discovered in 1986, appears to be less virulent than HIV-1, but also may have a longer latency period.

Immunofluorescent assay (IFA) A blood test sometimes used to confirm ELISA results instead of using the Western blotting. In an IFA test, HIV antigen is mixed with a fluorescent compound and then with a sample of the patient's blood. If HIV antibody is present, the mixture will fluoresce when examined under ultraviolet light.

Lymphocyte A type of white blood cell that is important in the formation of antibodies. Doctors can monitor the health of AIDS patients by measuring the number or proportion of certain types of lymphocytes in the patient's blood.

Macrophage A large white blood cell, found primarily in the bloodstream and connective tissue, that helps the body fight off infections by ingesting the disease organism. HIV can infect and kill macrophages.

Monocyte A large white blood cell that is formed in the bone marrow and spleen. About 4% of the white blood cells in normal adults are monocytes.

Opportunistic infection An infection that develops only when a person's immune system is weakened, as happens to AIDS patients.

Polymerase chain reaction (PCR) A test performed to evaluate false-negative results to the ELISA and Western blot tests. In PCR testing, numerous copies of a gene are made by separating the two strands of DNA containing the gene segment, marking its location, using DNA polymerase to make a copy, and then continuously replicating the copies. The amplification of gene sequences that are associated with HIV allows for detection of the virus by this method.

Retrovirus A virus that contains a unique enzyme called reverse transcriptase that allows it to replicate within new host cells.

Seroconversion The change from HIV-negative to HIV-positive status during blood testing. Persons who are HIV-positive are called seroconverters.

Serology The analysis of the contents and properties of blood serum.

Serum The part of human blood that remains liquid when blood cells form a clot. Human blood serum is clear light yellow in color.

T cells Lymphocytes that originate in the thymus gland. T cells regulate the immune system's response to infections, including HIV. CD4 lymphocytes are a subset of T lymphocytes.

Viral load test A new blood test for monitoring the speed of HIV replication in AIDS patients. The viral load test is based on PCR techniques and supplements the CD4+ cell count tests.

Western blot A technique developed in 1979 that is used to confirm ELISA results. HIV antigen is purified by electrophoresis and attached by blotting to a nylon or nitrocellulose filter. The patient's serum is reacted against the filter, followed by treatment with developing chemicals that allow HIV antibody to show up as a colored patch or blot. If the patient is HIV-positive, there will be stripes at specific locations for two or more viral proteins. A negative result is blank.

WBC differential A white blood cell count in which the technician classifies the different white blood cells by type as well as calculating the number of each type. A WBC differential is necessary to calculate the absolute CD4+ lymphocyte count.

The latest generation of ELISA tests are 99.5% sensitive to HIV. Occasionally, the ELISA test will be positive for a patient without symptoms of AIDS from a low-risk group. Because this result is likely to be a false-positive, the ELISA must be repeated on the same sample of the patient's blood. If the second ELISA is positive, the result should be confirmed by the Western blot test.

WESTERN BLOT (IMMUNOBLOT). The Western blot or immunoblot test is used as a reference procedure to confirm the diagnosis of AIDS. In Western blot testing, HIV antigen is purified by electrophoresis (large protein molecules are suspended in a gel and separated from one another by running an electric current through the gel). The HIV antigens are attached by blotting to a nylon or nitrocellulose filter. The patient's serum is reacted against the filter, followed by treatment with developing chemicals that allow HIV antibody to show up as a colored patch or blot. A commercially produced Western blot test for HIV-1 is now available. It consists of a prefabricated strip that is incubated with a sample of the patient's blood serum and the developing chemicals. About nine different HIV-1 proteins can be detected in the blots.

When used in combination with ELISA testing, Western blot testing is 99.9% specific. It can, however, yield false negatives in patients with very early HIV infection and in those infected by HIV-2. In some patients the Western blot yields indeterminate results.

IMMUNOFLUORESCENCE ASSAY (IFA). This method is sometimes used to confirm ELISA results instead of Western blotting. An IFA test detects the presence of HIV antibody in a sample of the patient's serum by mixing HIV antigen with a fluorescent chemical, adding the blood sample, and observing the reaction under a microscope with ultraviolet light.

POLYMERASE CHAIN REACTION (PCR). This test is used to evaluate the very small number of AIDS patients with false-negative ELISA and Western blot tests. These patients are sometimes called antibody-negative asymptomatic (without symptoms) carriers, because they do not have any symptoms of AIDS and there is no detectable quantity of antibody in the blood serum. Antibody-negative asymptomatic carriers may be responsible for the very low ongoing risk of HIV infection transmitted by blood transfusions. It is estimated that the risk is between 1 in 10,000 and 1 in 100,000 units of transfused blood.

The polymerase chain reaction (PCR) test can measure the presence of viral nucleic acids in the patient's blood even when there is no detectable antibody to HIV. This test works by amplifying the presence of HIV nucleic acids in a blood sample. Numerous copies of a gene are made by separating the two strands of DNA containing the gene segment, marking its location, using DNA polymerase to make a copy, and then continuously replicating the copies. It is questionable whether PCR will replace Western blotting as the method of confirming AIDS diagnoses. Although PCR can detect the low number of persons (1%) with HIV infections that have not yet generated an antibody response to the virus, the overwhelming majority of infected persons will be detected by ELISA screening within one to three months of infection. In addition, PCR testing is based on present knowledge of the genetic sequences in HIV. Since the virus is continually generating new variants, PCR testing could yield a false negative in patients with these new variants. In 2004, researchers reported on a new test that was more sensitive to HIV, detecting the infection in as little as 12 days after infection. However, the manufacturer was still seeking FDA approval for the test, which would cost about the same as PCR testing.

In 1999, the U.S. Food and Drug Administration (FDA) approved an HIV home testing kit. The kit contained multiple components, including material for specimen collection, a mailing envelope to send the specimen to a laboratory for analysis, and provides pre- and post-test counseling. It uses a finger prick process for blood collection. Other tests have been in development that would allow patients to monitor their own therapy in the home without sending out for results.

Prognostic tests

Blood tests to evaluate patients already diagnosed with HIV infection are as important as the diagnostic tests. Because AIDS has a long latency period, some persons may be infected with the virus for 10 years or longer before they develop symptoms of AIDS. These patients are sometimes called antibody-positive asymptomatic carriers. Prognostic tests also help drug researchers evaluate the usefulness of new medications in treating AIDS.

BLOOD CELL COUNTS. Doctors can measure the number or proportion of certain types of cells in an AIDS patient's blood to see whether and how rapidly the disease is progressing, or whether certain treatments are helping the patient. These cell count tests include:

  • Complete blood count (CBC). A CBC is a routine analysis performed on a sample of blood taken from the patient's vein with a needle and vacuum tube. The measurements taken in a CBC include a white blood cell count (WBC), a red blood cell count (RBC), the red cell distribution width, the hematocrit (ratio of the volume of the red blood cells to the blood volume), and the amount of hemoglobin (the blood protein that carries oxygen). Although CBCs are used on more than just AIDS patients, they can help the doctor determine if an AIDS patient has an advanced form of the disease. Specific AIDS-related signs in a CBC include a low hematocrit, a sharp decrease in the number of blood platelets, and a low level of a certain type of white blood cell called neutrophils.
  • Absolute CD4+ lymphocytes. A lymphocyte is a type of white blood cell that is important in the formation of an immune response. Because HIV targets CD4+ lymphocytes, their number in the patient's blood can be used to track the course of the infection. This blood cell count is considered the most accurate indicator for the presence of an opportunistic infection in an AIDS patient. The absolute CD4+ lymphocyte count is obtained by multiplying the patient's white blood cell count (WBC) by the percentage of lymphocytes among the white blood cells, and multiplying the result by the percentage of lymphocytes bearing the CD4+ marker. An absolute count below 200-300 CD+4 lymphocytes in 1 cubic millimeter (mm3) of blood indicates that the patient is vulnerable to some opportunistic infections.
  • CD4+ lymphocyte percentage. Some doctors think that this is a more accurate test than the absolute count because the percentage does not depend on a manual calculation of the number of types of different white blood cells. A white blood cell count that is broken down into categories in this way is called a WBC differential.

It is important for doctors treating AIDS patients to measure the lymphocyte count on a regular basis. Experts consulted by the United States Public Health Service recommend the following frequency of serum testing based on the patient's CD4+ level:

  • CD4+ count more than 600 cells/mm3: Every six months.
  • CD4+ count between 200-600 cells/mm3: Every three months.
  • CD4+ count less than 200 cells/mm3: Every three months.

When the CD4+ count falls below 200 cells/mm3, the doctor will put the patient on a medication regimen to protect him or her against opportunistic infections.

HIV VIRAL LOAD TESTS. Another type of blood test for monitoring AIDS patients is the viral load test. It supplements the CD4+ count, which can tell the doctor the extent of the patient's loss of immune function, but not the speed of HIV replication in the body. The viral load test is based on PCR techniques and can measure the number of copies of HIV nucleic acids. Successive test results for a given patient's viral load are calculated on a base 10 logarithmic scale.

ORAL HIV TESTS. Scientists have developed oral HIV tests that can be conducted with saliva samples. One of the unintented effects of these tests is the misperception that HIV can be transmitted through saliva. Still, they present an excellent alternative to blood sample testing.

RAPID HIV TESTS. Researchers constantly work on more rapid tests for HIV that can be done in physician offices or by less skilled people and more convenient locations in developing countries. A finger-stick test that can be read quickly from a whole blood sample had shown promising results in the fall of 2003. Another test, called the VScan test kit, requires no refrigeration or electricity and can safely be stored at room temperature. Even if the positive results must be confirmed by ELISA or Western blotting, an accurate initial rapid test can help screen populations for HIV antibodies.

In 2004, a new three-minute test for HIV was lunched in the United States under FDA approval. The hope of this test is that health care providers such as family practice physician offices can quickly test a patient in the office and provide results while the patient waits, rather than sending results to a lab.

BETA2-MICROGLOBULIN (BETA2M). Beta-microglobulin is a protein found on the surface of all human cells with a nucleus. It is released into the blood when a cell dies. Although rising blood levels of β2M are found in patients with cancer and other serious diseases, a rising β2M blood level can be used to measure the progression of AIDS.

P24 ANTIGEN CAPTURE ASSAY. Found in the viral core of HIV, p24 is a protein that can be measured by the ELISA technique. Doctors can use p24 assays to measure the antiviral activity of the patient's medications. In addition, the p24 assay is sometimes useful in detecting HIV infection before seroconversion. However, p24 is consistently present in only 25% of persons infected with HIV.

GENOTYPIC DRUG RESISTANCE TEST. Genotypic testing can help determine whether specific gene mutations, common in people with HIV, are causing drug resistance and drug failure. The test looks for specific genetic mutations within the virus that are known to cause resistance to certain drugs used in HIV treatment. For example the drug 3TC, also known as lamivudine (Epivir), is not effective against strains of HIV that have a mutation at a particular position on the reverse transcriptase proteinamino acid 184known as M184V (MV, methionine to valine). So if the genotypic resistance test shows a mutation at position M184V, it is likely the person is resistant to 3TC and not likely to respond to 3TC treatment. Genotypic tests are only effective if the person is already taking antiviral medication and if the viral load is greater than 1,000 copies per milliliter (mL) of blood. The cost of the test, usually between $300 and $500, is usually now covered by many insurance plans.

PHENOTYPIC DRUG RESISTANCE TESTING. Phenotypic testing directly measures the sensitivity of a patient's HIV to particular drugs and drug combinations. To do this, it measures the concentration of a drug required to inhibit viral replication in the test tube. This is the same method used by researchers to determine whether a drug might be effective against HIV before using it in human clinical trials. Phenotypic testing is a more direct measurement of resistance than genotypic testing. Also, unlike genotypic testing, phenotypic testing does not require a high viral load but it is recommended that persons already be taking antiretroviral drugs. The cost is between $700 and $900 and is now covered by many insurance plans.

AIDS serology in children

Children born to HIV-infected mothers may acquire the infection through the mother's placenta or during the birth process. Public health experts recommend the testing and monitoring of all children born to mothers with HIV. Diagnostic testing in children older than 18 months is similar to adult testing, with ELISA screening confirmed by Western blot. Younger infants can be diagnosed by direct culture of the HIV virus, PCR testing, and p24 antigen testing. These techniques allow a pediatrician to identify 50% of infected children at or near birth, and 95% of cases in infants three to six months of age.

Preparation

Preparation and aftercare are important parts of AIDS diagnostic testing. Doctors are now advised to take the patient's emotional, social, economic, and other circumstances into account and to provide counseling before and after testing. Patients are generally better able to cope with the results if the doctor has spent some time with them before the blood test explaining the basic facts about HIV infection and testing. Many doctors now offer this type of informational counseling before performing the tests.

Aftercare

If the test results indicate that the patient is HIV-positive, he or she will need counseling, information, referral for treatment, and support. Doctors can either counsel the patient themselves or invite an experienced HIV counselor to discuss the results of the blood tests with the patient. They also will assess the patient's emotional and psychological status, including the possibility of violent behavior and the availability of a support network.

Risks

The risks of AIDS testing are primarily related to disclosure of the patient's HIV status rather than to any physical risks connected with blood testing. Some patients are better prepared to cope with a positive diagnosis than others, depending on their age, sex, health, resources, belief system, and similar factors.

Normal results

Normal results for ELISA, Western blot, IFA, and PCR testing are negative for HIV antibody.

Normal results for blood cell counts:

  • WBC differential: Total lymphocytes 24-44% of the white blood cells.
  • Hematocrit: 40-54% in men; 37-47% in women.
  • T cell lymphocytes: 644-2200/mm3, 60-88% of all lymphocytes.
  • B cell lymphocytes: 82-392/mm3, 3-20% of all lymphocytes.
  • CD4+ lymphocytes: 500-1200/mm3, 34-67% of all lymphocytes.

Abnormal results

The following results in AIDS tests indicate progression of the disease:

  • Percentage of CD4+ lymphocytes: less than 20% of all lymphocytes.
  • CD4+ lymphocyte count: less than 200 cells/mm3.
  • Viral load test: Levels more than 5000 copies/mL.
  • β:-2-microglobulin: Levels more than 3.5 mg/dL.
  • P24 antigen: Measurable amounts in blood serum.

Resources

BOOKS

Bennett, Rebecca, and Erin, Charles A., editors. HIV and AIDS Testing, Screening, and Confidentiality: Ethics, Law, and Social Policy. Oxford, England: Oxford University Press, 2001.

PERIODICALS

"Finger-stick Test is Accurate and Acceptable to Women in Thailand." Drug Week (September 5, 2003): 168.

Kaplan, Edward H., and Glen A. Satten. "Repeat Screening for HIV: When to Test and Why." The Journal of the American Medical Association.

Medical Devices & Surgical Technology Week (September 12, 2004): 102.

"Researcher Developing Home Test Kit for HIV Therapies." Medical Devices & Surgical Technology Week (December 23, 2001): 2.

"Researchers Report New Ultra-sensitive AIDS Test." Biotech Week (July 14, 2004): 246.

Weinhardt, Lance S., et al. "Human Immunodeficiency Virus Testing and Behavior Change." Archives of Internal Medicine (May 22, 2000): 1538.

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AIDS

Definition

Acquired immune deficiency syndrome (AIDS) is an infectious disease caused by the human immunodeficiency virus (HIV). AIDS is the advanced form of infection caused by HIV and typically only manifests itself after a long latency period after initial HIV infection. AIDS is a fatal disease for which there is currently no cure.

Description

First recognized in the United States in 1981, AIDS is considered one of the most devastating public health problems in recent history. The Centers for Disease Control and Prevention (CDC) has estimated that, as of 2003, between 1,039,000 and 1,185,000 people in the United States were HIV-positive, and 944,305 were living with AIDS. Of 2004 adult AIDS cases, 17,691 were believed to have contracted HIV from same sex male intercourse, 9,152 from intravenous drug use, and 13,128 from heterosexual contact. There are an estimated 42,500 new HIV infections each year in the U.S. The Joint United Nations Program on HIV/AIDS estimates that, worldwide during the year 2005, an estimated 3.1 million people had died of AIDS, and 8 million adults and 2.3 million children were living with HIV/AIDS. Approximately 95% of persons with HIV/AIDS were living in developing countries.

Risk factors

HIV/AIDS can be transmitted in several ways. The various routes of transmission (and associated risk factors) include:

  • Sexual contact. Persons at greatest risk are those who do not practice safe sex (sex with a condom), those who are not monogamous, those who engage in anal intercourse, and those who have sex with a partner with symptoms of advanced HIV infection and/or other sexually transmitted diseases (STDs). In the United States and Europe, most cases of sexually transmitted HIV infection arise via same sex contact, whereas in Africa the disease is spread primarily through heterosexual intercourse.
  • Transmission in pregnancy. High-risk mothers include women who use intravenous drugs, women who have sex with bisexual men, women who are married to men who have an abnormal blood condition called hemophilia (a condition requiring blood transfusions), and women living in areas with a high rate of HIV infection among heterosexuals. The chances of transmitting HIV from mother to child are higher in women who are in advanced stages of the disease. Breast feeding increases the risk of transmission by 10%-20%, and vaginal delivery doubles the risk of transmitting HIV to the child. Zidovudine (AZT) given to the mother during pregnancy and given to the baby soon after delivery have been shown to decrease the risk of HIV transmission to the child.
  • Exposure to contaminated blood or blood products. With the introduction of blood product screening in the mid-1980s, the incidence of HIV transmission in blood transfusions has dropped to 1 in 100,000. Among users of intravenous drugs, risk increases with the duration of injection use, the frequency of needle sharing, the number of persons who share a needle, and the number of AIDS cases in the local population.
  • Exposure of health care professionals to infected blood. Studies have shown that 0.32% of highly exposed health care workers have become infected with HIV through occupational exposure. Needle injuries are the most common exposure route. Risk factors for contracting HIV from a needle injury include a deep injection, a needle that has been used in an artery or vein, blood visibly apparent on the needle prior to injury, and blood from a patient with end-stage AIDS. There is evidence that administration of zidovudine (AZT) to the injured worker soon after HIV exposure decreases risk of infection.

HIV is not transmitted by handshakes, coughing, sneezing, or other casual non-sexual contact. There is currently no evidence that HIV can be transmitted through bloodsucking insects such as mosquitoes.

AIDS in women

HIV remains an important cause of death and illness in women. In the US, AIDS was the fifth leading cause of death among women aged 25-44 in 1998. In 2003, 27% of new HIV diagnoses were in women. Although HIV infected women have been observed to die earlier than men, it is believed that this difference in survival rates is caused by differences in access to care and delayed treatment rather than biological differences in disease progression.

AIDS in children

Since AIDS can be transmitted from an infected mother to the child during pregnancy, during the birth process, or through breast milk, all infants born to HIV-positive mothers are a high-risk group. In 1999, 78% of new HIV cases in women were in females of childbearing age. Without prenatal intervention, between 20-40% of children born to HIV-positive women will become infected with the virus.

AIDS is one of the 10 leading causes of death in children between one and four years of age. The interval between exposure to HIV and the development of AIDS is shorter in children than in adults. Infants infected with HIV have a 20-30% chance of developing AIDS within a year and dying before age three. In the remainder, AIDS progresses more slowly; the average child patient survives to seven years of age. Some survive into early adolescence.

Causes and symptoms

Because HIV destroys immune system cells, AIDS is a disease that can affect any of the body's major organ systems. HIV attacks the body through three disease processes: immunodeficiency, autoimmunity, and nervous system dysfunction.

Immunodeficiency describes the condition in which the body's immune response is damaged, weakened, or is not functioning properly. In AIDS, immunodeficiency results from the way that the virus binds to a protein called CD4, which is found on the surface of certain subtypes of white blood cells, including helper T cells, macrophages, and monocytes. Once HIV attaches to an immune system cell, it can replicate within the cell and kill the cell in ways that are still not completely understood. In addition to killing some lymphocytes directly, the AIDS virus disrupts the functioning of the remaining CD4 cells. Because the immune system cells are destroyed, many different types of infections and cancers that take advantage of a person's weakened immune system (opportunistic) can develop.

Autoimmunity is a condition in which the body's immune system produces antibodies that work against its own cells. Antibodies are specific proteins produced in response to exposure to a specific, usually foreign, protein or particle called an antigen. In this case, the body produces antibodies that bind to blood platelets that are necessary for proper blood clotting and tissue repair. Once bound, the antibodies mark the platelets for removal from the body, and they are filtered out by the spleen. Some AIDS patients develop a disorder, called immune-related thrombocytopenia purpura (ITP), in which the number of blood platelets drops to abnormally low levels.

HIV also infects some susceptible cells in the central nervous system. The exact mechanism of HIV entry into the brain is unknown. Possible modes of entry across the blood-brain barrier include HIV entry as a single cell-free viral particle (virion), entry via infected monocyte or lymphocyte, and infection of endothelial cells (cells forming brain border). Regardless of the mechanism, evidence suggests that the cerebral spinal fluid is seeded with HIV very early in the infection process.

Although not all patients will follow them precisely, the course of AIDS generally progresses through the three stages (acute retroviral syndrome, latency period, and late-stage AIDS) that follow.

Acute retroviral syndrome

Acute retroviral syndrome is a term used to describe a group of symptoms that can resemble mononucleosis and that may be the first sign of HIV infection in 50-70% of all patients and 45-90% of women. The symptoms may include fever, fatigue, muscle aches, loss of appetite, digestive disturbances, weight loss, skin rashes, headache, and chronically swollen lymph nodes (lymphadenopathy). Approximately 25-33% of patients will experience a form of meningitis during this phase in which the membranes that cover the brain and spinal cord become inflamed. Acute retroviral syndrome develops between one and six weeks after infection and lasts for two to three weeks. Blood tests during this period will indicate the presence of virus (viremia) and the appearance of the viral p24 antigen in the blood.

Latency period

After the HIV virus enters a patient's lymph nodes during the acute retroviral syndrome stage, the disease becomes latent for as many as 10 years or more before symptoms of advanced disease develop. During latency, the virus continues to replicate in the lymph nodes, where it may cause one or more of the following conditions.

PERSISTENT GENERALIZED LYMPHADENOPATHY (PGL). Persistent generalized lymphadenopathy, or PGL, is a condition in which HIV continues to produce chronic painless swellings in the lymph nodes during the latency period. The lymph nodes that are most frequently affected by PGL are those in the areas of the neck, jaw, groin, and armpits. PGL affects between 50-70% of patients during latency.

CONSTITUTIONAL SYMPTOMS. Many patients will develop low-grade fevers, chronic fatigue, and general weakness. HIV may also cause a combination of food malabsorption, loss of appetite, and increased metabolism that contribute to the so-called AIDS wasting or wasting syndrome.

OTHER ORGAN SYSTEMS. At any time during the course of HIV infection, patients may suffer from a yeast infection in the mouth called thrush, open sores or ulcers, or other infections of the mouth; diarrhea and other gastrointestinal symptoms that cause malnutrition and weight loss; diseases of the lungs and kidneys; and degeneration of the nerve fibers in the arms and legs. HIV infection of the nervous system leads to general loss of strength, loss of reflexes, and feelings of numbness or burning sensations in the feet or lower legs.

Late-stage AIDS

Late-stage AIDS is usually marked by a sharp decline in the number of CD4+ lymphocytes, followed by a rise in the frequency of opportunistic infections and cancers. Doctors monitor the number and proportion of CD4+ lymphocytes in the patient's blood in order to assess the progression of the disease and the effectiveness of different medications. About 10% of infected individuals never progress to this overt stage of the disease.

OPPORTUNISTIC INFECTIONS. Once the patient's CD4+ lymphocyte count falls below 200 cells/mm3, the patient is at risk for a variety of opportunistic infections. The infectious organisms may include the following:

  • Fungi. The most common fungal disease associated with AIDS is Pneumocystis cariniipneumonia (PCP). About 70%-80% of AIDS patients will have at least one episode of PCP prior to death. PCP is the immediate cause of death in 15-20% of AIDS patients. It is an important measure of a patient's prognosis. Other fungal infections include a yeast infection of the mouth (candidiasis or thrush) and cryptococcal meningitis.
  • Protozoa. Toxoplasmosis is a common opportunistic infection in AIDS patients that is caused by a protozoan. Other diseases in this category include amebiasis and cryptosporidiosis.
  • Mycobacteria. AIDS patients may develop tuberculosis or MAC infections. MAC infections are caused by Mycobacterium avium-intracellulare, and occur in about 40% of AIDS patients.
  • Bacteria. AIDS patients are likely to develop bacterial infections of the skin and digestive tract.
  • Viruses. AIDS patients are highly vulnerable to cytomegalovirus (CMV), herpes simplex virus (HSV), varicella zoster virus (VZV), and Epstein-Barr virus (EBV) infections. Another virus, JC virus, causes progressive destruction of brain tissue in the brain stem, cerebrum, and cerebellum (multifocal leukoencephalopathy or PML), which is regarded as an AIDS-defining illness by the Centers for Disease Control and Prevention.

AIDS DEMENTIA COMPLEX AND NEUROLOGIC COMPLICATIONS. AIDS dementia complex is a late complication of the disease. It is unclear whether it is caused by the direct effects of the virus on the brain or by intermediate causes. AIDS dementia complex is marked by loss of reasoning ability, loss of memory, inability to concentrate, apathy and loss of initiative, and unsteadiness or weakness in walking. Some patients also develop seizures. There are no specific treatments for AIDS dementia complex.

MUSCULOSKELETAL COMPLICATIONS. Patients in late-stage AIDS may develop inflammations of the muscles, particularly in the hip area, and may have arthritis-like pains in the joints.

ORAL SYMPTOMS. In addition to thrush and painful ulcers in the mouth, patients may develop a condition called hairy leukoplakia of the tongue. This condition is also regarded by the CDC as an indicator of AIDS. Hairy leukoplakia is a white area of diseased tissue on the tongue that may be flat or slightly raised. It is caused by the Epstein-Barr virus.

AIDS-RELATED CANCERS. Patients with late-stage AIDS may develop Kaposi's sarcoma (KS), a skin tumor that primarily affects homosexual men. KS is the most common AIDS-related malignancy. It is characterized by reddish-purple blotches or patches (brownish in persons with darker skin) on the skin or in the mouth. About 40% of patients with KS develop symptoms in the digestive tract or lungs. KS may be caused by a herpes virus-like sexually transmitted disease agent rather than HIV.

The second most common form of cancer in AIDS patients is a tumor of the lymphatic system (lymphoma). AIDS-related lymphomas often affect the central nervous system and develop very aggressively.

Invasive cancer of the cervix is an important diagnostic marker of AIDS in women.

Diagnosis

Because HIV infection produces such a wide range of symptoms, the CDC has drawn up a list of 34 conditions regarded as defining AIDS. The physician will use the CDC list to decide whether the patient falls into one of these three groups:

  • definitive diagnoses with or without laboratory evidence of HIV infection
  • definitive diagnoses with laboratory evidence of HIV infection
  • presumptive diagnoses with laboratory evidence of HIV infection

Physical findings

Almost all the symptoms of AIDS can occur with other diseases. The general physical examination may range from normal findings to symptoms that are closely associated with AIDS. These symptoms are hairy leukoplakia of the tongue and Kaposi's sarcoma. When the doctor examines the patient, he or she will look for the overall pattern of symptoms rather than any one finding.

Laboratory tests for HIV infection

BLOOD TESTS (SEROLOGY). The first blood test for AIDS was developed in 1985. At present, patients who are being tested for HIV infection are usually given an enzyme-linked immunosorbent assay (ELISA) test for the presence of HIV antibody in their blood. Positive ELISA results are then tested with a Western blot or immunofluorescence (IFA) assay for confirmation. The combination of the ELISA and Western blot tests is more than 99.9% accurate in detecting HIV infection within four to eight weeks following exposure. Indeterminate test results are possible (positive ELISA but non-confirmatory Western blot result) if the tests are given within the window period after infection (up to eight weeks after infection, but may be longer). In these indeterminate cases, the ELISA and Western blot should be repeated every three months until a definitive result is made. The patient should be considered HIV positive until proven otherwise. The polymerase chain reaction (PCR) test can be used to detect the presence of viral nucleic acids in the very small number of HIV patients who have false-negative results on the ELISA and Western blot tests.

OTHER LABORATORY TESTS. In addition to diagnostic blood tests, other blood tests are used to track the course of AIDS in patients that have already been diagnosed, including blood counts, viral load tests, p24 antigen assays, and measurements of β2-microglobulin (β2M).

Doctors will use a wide variety of tests to diagnose the presence of opportunistic infections, cancers, or other disease conditions in AIDS patients. Tissue biopsies, samples of cerebrospinal fluid, and sophisticated imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography scans (CT) are used to diagnose AIDS-related cancers, some opportunistic infections, damage to the central nervous system, and wasting of the muscles. Urine and stool samples are used to diagnose infections caused by parasites. AIDS patients are also given blood tests for syphilis and other sexually transmitted diseases.

Diagnosis in children

Diagnostic blood testing in children older than 18 months is similar to adult testing, with ELISA screening confirmed by Western blot. Younger infants can be diagnosed by direct culture of the HIV virus, PCR testing, and p24 antigen testing.

In terms of symptoms, children are less likely than adults to have an early acute syndrome. They are, however, likely to have delayed growth, a history of frequent illness, recurrent ear infections, a low blood cell count, failure to gain weight, and unexplained fevers. Children with AIDS are more likely to develop bacterial infections, inflammation of the lungs, and AIDS-related brain disorders than are HIV-positive adults.

Treatment

Because AIDS is a fatal disease, AIDS therapies focus on improving the quality and length of life for AIDS patients by slowing or halting the replication of the virus, and treating or preventing infections and cancers that take advantage of a person's weakened immune system. No vaccine is effective in preventing HIV infection.

Treatment for AIDS covers four considerations:

TREATMENT OF OPPORTUNISTIC INFECTIONS AND MALIGNANCIES. Most AIDS patients require complex long-term treatment with medications for infectious diseases. This treatment is often complicated by the development of resistance in the disease organisms. AIDS-related malignancies in the central nervous system are usually treated with radiation therapy. Cancers elsewhere in the body are treated with chemotherapy.

PROPHYLACTIC TREATMENT FOR OPPORTUNISTIC INFECTIONS. Prophylactic treatment is treatment that is given to prevent disease. AIDS patients with a history of Pneumocystis pneumonia; with CD4+ counts below 200 cells/mm3 or 14% of lymphocytes; weight loss; or thrush should be given prophylactic medications. The three drugs given are trimethoprim-sulfamethoxazole, dapsone, or pentamidine in aerosol form.

ANTI-RETROVIRAL TREATMENT. In recent years researchers have developed drugs that suppress HIV replication, as distinct from treating its effects on the body. These drugs fall into three classes:

  • Nucleoside reverse transcriptase inhibitors (NRTIs). These drugs work by looking very similar to the molecules acted upon by the HIV enzyme reverse transcriptase. Reverse transcriptase binds to these drugs, which in turn stop the viral replication process. These drugs include zidovudine, didanosine (ddi), zalcitabine (ddC), stavudine (d4T), lamivudine (3TC), and abacavir (ABC).
  • Non-nucleoside reverse transcriptase inhibitors (NNRTIs). These drugs de-activate the HIV enzyme reverse transcriptase. This class of drugs includes nevirapine (NVP), delavirdine (DLV), and efavirenz (EFV).

Protease inhibitors. A new class of drugs, protease inhibitors are effective against HIV strains that have developed resistance to nucleoside analogues and are used in combination with them. These compounds include saquinavir (SQV), ritonavir (RJV), indinavir (IDV), nelfinavir (NFV), and amprenavir (APV).

New combinations of therapies are also being developed, primarily to improve adherence. Trizivir for the treatment of HIV in adults and adolescents is a fixed-dose combination of abacavir, zidovudine, and lamivudine. Another combination therapy, Combivir, combines lamivudine and zidovudine. Both Trizivir and Combivir are combinations of NRTIs that combine drugs into a single dosage, making it easier for patients to comply with their dosage regimens.

Treatment guidelines for these agents are continually being modified as new medications are developed and introduced. Guidelines for when to start anti-retroviral therapy have been published separately by the International AIDS Society—United States and U.S. Department of Health and Human Services. These guidelines are very similar and base their recommendations on a patient's CD4 counts, viral load, and clinical symptoms.

In terms of specific treatment approaches, the 2005 guidelines from the U.S. Department of Health and Human Services suggest two strategies for initial treatment, both of which use combinations of drugs: two nucleosides and a protease inhibitor, or two nucleosides and a non-nucleoside drug. Over time, treatment changes may be required; factors that must be considered when changing treatment regimens include drug toxicity, clinical symptoms, viral load, CD4 counts, adherence to current and future medications, and other viable treatment options.

STIMULATION OF BLOOD CELL PRODUCTION. Because many patients with AIDS suffer from abnormally low levels of both red and white blood cells, they may be given medications to stimulate blood cell production. Epoetin alfa (erythropoietin) may be given to anemic patients. Patients with low white blood cell counts may be given filgrastim or sargramostim.

Risk of acquiring HIV infection by entry site
Entry site Risk virus reaches entry site Risk virus enters Risk inoculated
Source: Hopp, J.W. and E.A. Rogers. AIDS and the Allied Health Professions. Philadelphia: F.A. Davis Co., 1989.
ConjuntivaModerateModerateVery low
Oral mucosaModerateModerateLow
Nasal mucosaLowLowVery low
Lower respiratoryVery lowVery lowVery low
AnusVery highVery highVery high
Skin, intactVery lowVery lowVery low
Skin, brokenLowHighHigh
Sexual:
   VaginaLowLowMedium
   PenisHighLowLow
   Ulcers (STD)HighHighVery high
Blood:
   ProductsHighHighHigh
   Shared needlesHighHighVery high
   Accidental needleLowHighLow
Traumatic woundModestHighHigh
PerinatalHighHighHigh

Treatment in women

Treatment of pregnant women with HIV is particularly important because anti-retroviral therapy has been shown to reduce transmission to the infant by 65%.

Prognosis

No cure for AIDS has been discovered. Treatment stresses aggressive combination drug therapy for those patients with access to the expensive medications and who tolerate them adequately. The use of these multi-drug therapies, called highly active antiretroviral therapies or HAART, has significantly reduced the numbers of deaths in the United states resulting from AIDS. The data is still inconclusive, but the potential exists to prolong life indefinitely using these and other drug therapies to boost the immune system, keep the virus from replicating, and ward off opportunistic infections and malignancies.

Prognosis after the latency period depends on the patient's specific symptoms and the organ systems affected by the disease. Patients with AIDS-related lymphomas of the central nervous system die within two to three months of diagnosis; those with systemic lymphomas may survive for eight to ten months.

Health care team roles

The physician oversees the treatment strategy and patient evaluation for patients who are HIV-positive and/or have AIDS. Adherence to treatment is a critical aspect of clinical care in AIDS, and nurses play a key role in educating patients and providing them with adherence tools. Nurses, social workers, and psychologists can also be trained as HIV counselors to advise patients about HIV testing and, if necessary, to assist and guide patients in adjusting to a life with HIV. During end-stage AIDS, nurses, social workers, and other hospice workers ensure that patients do not experience unnecessary pain and discomfort.

Prevention

As of 2005, there is no vaccine effective against HIV/AIDS. Several vaccines are being investigated, however, both to prevent initial HIV infection and as a therapeutic treatment to prevent HIV from progressing to full-blown AIDS.

Several types of prevention programs have been found to be effective in reducing sexual transmission of HIV. These include:

  • targeted education for at-risk groups, emphasizing preventive practices such as condom use, monogamy, and HIV testing prior to beginning a sexual relationship
  • counseling with or without testing for HIV and other sexually transmitted diseases
  • education programs in institutions such as the military, prisons, and the workplace
  • greater access to condoms

Preventive measures for other modes of transmission include:

  • Making clean needles more available and discouraging intravenous drug users from sharing needles.
  • Encouraging health care professionals to take all necessary precautions by wearing gloves and masks when handling body fluids.
  • Encouraging health care institutions to provide safer medical devices such as self-sheathing needles and retracting and/or needleless intravenous systems.
  • Informing individuals who are planning to undergo major surgery that they can donate blood in advance to prevent a risk of infection from a blood transfusion. (However, blood and blood products are carefully monitored.)

KEY TERMS

Acute retroviral syndrome— A group of symptoms resembling mononucleosis that often are the first sign of HIV infection in 50-70% of all patients and 45-90% of women.

AIDS dementia complex— A type of brain dysfunction caused by HIV infection that causes difficulty thinking, confusion, and loss of muscular coordination.

Antibody— A specific protein produced by the immune system in response to a specific foreign protein or particle called an antigen.

Antigen— Any substance that stimulates the body to produce antibody.

Autoimmunity— A condition in which the body's immune system produces antibodies in response to its own tissues or blood components instead of foreign particles or microorganisms.

CD4— A type of protein molecule in human blood, sometimes called the T4 antigen, that is present on the surface of 65% of immune cells. The HIV virus infects cells that have CD4 surface proteins, and as a result, depletes the number of T cells, B cells, natural killer cells, and monocytes in the patient's blood. Most of the damage to an AIDS patient's immune system is done by the virus' destruction of CD4+ lymphocytes.

Hairy leukoplakia of the tongue— A white area of diseased tissue on the tongue that may be flat or slightly raised. It is caused by the Epstein-Barr virus and is an important diagnostic sign of AIDS.

Hemophilia— Any of several hereditary blood coagulation disorders occurring almost exclusively in males. Because blood does not clot properly, even minor injuries can cause significant blood loss that may require a blood transfusion, with its associated minor risk of infection.

Human immunodeficiency virus (HIV)— A transmissible retrovirus that causes AIDS in humans. Two forms of HIV are now recognized: HIV-1, which causes most cases of AIDS in Europe, North and South America, and most parts of Africa; and HIV-2, which is chiefly found in West African patients. HIV-2, discovered in 1986, appears to be less virulent than HIV-1 and may also have a longer latency period.

Immunodeficient— A condition in which the body's immune response is damaged, weakened, or is not functioning properly.

Kaposi's sarcoma— A cancer of the connective tissue that produces painless purplish red (in people with light skin) or brown (in people with dark skin) blotches on the skin. It is a major diagnostic marker of AIDS

Latent period— Also called incubation period, the time between infection with a disease-causing agent and the development of disease.

Lymphocyte— A type of white blood cell that is important in the formation of antibodies and that can be used to monitor the health of AIDS patients.

Lymphoma— A cancerous tumor in the lymphatic system that is associated with a poor prognosis in AIDS patients.

Macrophage— A large white blood cell, found primarily in the bloodstream and connective tissue, that helps the body fight off infections by ingesting the disease-causing organism. HIV can infect and kill macrophages.

Monocyte— A large white blood cell that is formed in the bone marrow and spleen. About 4% of the white blood cells in normal adults are monocytes.

Mycobacterium avium (MAC) infection— A type of opportunistic infection that occurs in about 40% of AIDS patients and is regarded as an AIDS-defining disease.

Non-nucleoside reverse transcriptase inhibitors— A newer class of anti-retroviral drugs that work by inhibiting the reverse transcriptase enzyme necessary for HIV replication.

Nucleoside analogue reverse transcriptase inhibitors— The first group of effective anti-retroviral medications. They work by interfering with HIV synthesis of its viral DNA.

Opportunistic infection— An infection by organisms that usually do not cause infection in people with healthy functioning immune systems.

Persistent generalized lymphadenopathy (PGL)— A condition in which HIV continues to produce chronic painless swellings in the lymph nodes during the latency period.

Pneumocystis carinii pneumonia (PCP)— An opportunistic infection caused by a fungus that is a major cause of death in patients with late-stage AIDS.

Progressive multifocal leukoencephalopathy (PML)— A disease caused by a virus that destroys white matter in localized areas of the brain. It is regarded as an AIDS-defining illness.

Protease inhibitors— A new class of anti-retroviral drugs used to treat AIDS that works by preventing the HIV protease enzyme from generating new functioning HIV viruses.

Protozoan— A single-celled, usually microscopic organism that is eukaryotic and, therefore, different from bacteria (prokaryotic).

Retrovirus— A virus that contains a unique enzyme called reverse transcriptase that allows it to replicate within new host cells.

T cells— Lymphocytes that originate in the thymus gland. T cells regulate the immune system's response to infections, including HIV. CD4 lymphocytes are a subset of T lymphocytes.

Thrush— A yeast infection of the mouth characterized by white patches on the inside of the mouth and cheeks.

Viremia— The measurable presence of virus in the bloodstream that is a characteristic of acute retroviral syndrome.

Wasting syndrome— A progressive loss of weight and muscle tissue caused by the AIDS virus.

  • Encouraging testing for HIV infection if there has been suspected exposure to HIV. If HIV infection is confirmed, sexual partners should be informed and, if necessary, receive medical attention.

Resources

BOOKS

Bartlett, John G., and Finkbeiner, Ann K. The Guide to Living With HIV Infection: Developed at the Johns Hopkins AIDS Clinic (Johns Hopkins Press Health Book). 5th ed. Baltimore: Johns Hopkins University Press, 2001.

Cohen, Oren J., Anthony S. Fauci. "Current Strategies in the Treatment of HIV Infection." In Advances in Internal Medicine. Vol. 46. Schrier, Robert W. et al. eds. St Louis: Mosby, Inc., 2001.

Kirton, Carl A. et al. eds. Handbook of HIV/AIDS Nursing St. Louis: Mosby, Inc., 2001.

Lahart, Christopher J. "Management of the Patient with HIV Infection." In Conn's Current Therapy. 3rd ed. Edited by Robert E. Rakel and Edward T. Bope. Philadelphia: WB Saunders Company, 2001.

Princeton, Douglas C. Manual of HIV/AIDS Therapy, 2000 Edition. Current Clinical Strategies, 2001.

Smith, Raymond A. ed. Encyclopedia of AIDS: A Social, Political, Cultural, and Scientific Record of the Hiv Epidemic. Penquin USA, 2001.

US Public Health Service, Department of Health Human Services, Infectious Disease Society of America. The 2001 Guidelines for the Use of Antiretroviral Agents in HIV-Infected Adults and Adolescents and the 1999 USPHS/IDSA Guidelines for the Prevention of Opportunistic Infections. International Medical Publishing, 2001.

PERIODICALS

Janoff E.N., and Smith, P.D. "Emerging Concepts in Gastrointestinal Aspects of HIV-1 Pathogenesis and Management." Gastroenterology (United States) 120, no 3 (February 2001): 607-21.

Kerr C. "Trizivir on the Market." Trends in Microbiology (England). 9, no 1 (January 2001): 13.

Neuwirth, RS. "Special Article: Hysteroscopy and Gynecology: Past, Present, and Future." Journal of American Association Gynecology Laparoscopy 8, no 2 (May 2001): 193-8.

Summers, T. "Public Policy for Health Care workers Infected with the Human Immunodeficiency Virus." Journal of the American Medical Association 285, no 7 (February 21, 2001): 882.

ORGANIZATIONS

Gay Men's Health Crisis. The Tisch Building, 119 West 24th Street, New York, NY 10011. (800) 243-7692. 〈http://www.gmhc.org/〉.

HIV/AIDS Treatment Information Service (ATIS). P.O. Box 6303, Rockville, MD 20849-6303. (800) 448-0440. 〈http://www.hivatis.org/〉.

National AIDS Hot Line. (800) 342-AIDS/2437 (English). (800) 344-SIDA (Spanish). (800) AIDS-TTY (hearing-impaired).

OTHER

Treatment. Centers for Disease Control and Prevention, Division of HIV/AIDS Prevention. August 2001. 〈http://www.cdc.gov/hiv/treatment.htm〉.

views updated

AIDS

Definition

Acquired immunodeficiency syndrome (AIDS) is an advanced form of HIV infection in which the patient has developed opportunistic infections or certain types of cancer and/or the CD4+ T cell count has dropped below 200 per microliter (200/?L). Human immunodeficiency virus (HIV) is a retrovirus—a type of virus that uses an enzyme called reverse transcriptase to enable it to become part of its host's DNA and replicate. As of 2008 there is no cure for AIDS and no vaccine against the infection.

Estimated numbers of AIDS cases, by year of diagnosis and selected characteristics, 2002–2006 and cumulative— United States and dependent areas
 Year of diagnosis  
 2002 2003 2004 2005 2006 Cumulative
Data for 50 states and the District of Columbia
Age at diagnosis (yrs)
      
50–543,2713,3643,4913,5273,68759,907
55–591,6071,6931,8361,8612,07132,190
60–5487286491387295517,303
≥6568276379172783515,074
Estimated numbers of deaths of persons with AIDS, by year of death and selected characteriscs, 2002–2006 and cumulative—United States and dependent areas
 Year of diagnosis  
 2002 2003 2004 2005 2006 Cumulative
source: Centers for Disease Control and Prevention. HIV/AIDS Surveillance Report, 2006. Vol. 18. Atlanta: U.S. Department of Health and Human Services. Centers for Disease Control and Prevention; 2008; p. 13 and p. 17. http://www.cdc.gov/hiv/topics/surveillance/resources/reports/.
(Illustration by GGS Information Services. Cengage Learning, Gale)
Data for 50 states and the District of Columbia Age at death (yrs)
50–542,3182,3732,5022,6452,34344,255
55–591,2091,3221,4251,5431,48025,123
60–5461670574179777114,315
6569177380786580514,393

Description

Background

HIV infection is thought to have emerged as a human disease in sub-Saharan Africa at some point in the mid-twentieth century, most likely when the virus made a species jump from chimpanzees into humans. The first cases of AIDS in the United States were reported in 1981 in a group of homosexual men in New York City. In the following years other cases of HIV transmission through blood transfusions were reported, followed by reports of children developing AIDS via transmission of the virus from an infected mother to her infant during childbirth. It is now known that HIV can be transmitted through direct contact of a mucous membrane or the bloodstream with a body fluid contaminated by the virus. Body fluids include breast milk, semen, and vaginal secretions as well as blood and saliva. Transmission can occur through oral, anal, or vaginal intercourse; blood transfusion; the use of contaminated hypodermic needles; breastfeeding; and needlestick injuries.

Stages

As of the early 2000s, HIV infection is usually described as progressing in three stages:

  • Primary HIV infection/acute retroviral syndrome (ARS). Some patients have no symptoms at this stage; however, about 30 percent develop acute retroviral syndrome (ARS) a few days or weeks after exposure. ARS is often mistaken for flu, strep throat, mononucleosis, or even secondary syphilis. The patient may or may not have developed antibodies to HIV (a process known as seroconversion) at this point; thus a test for HIV infection in this early period may not yield positive results even though the patient is in fact infected. In this stage the CD4 cell count is 500/?L or higher.
  • Clinically asymptomatic stage. The acute symptoms (if any) of the primary infection stage go away. The virus continues to replicate in the body for as long as 10 years, however, destroying the structures of the patient's lymph nodes and gradually depleting the CD4+ T cells that fight the infection. The CD4+ T cell count in this stage is between 500 and 200 cells per microliter.
  • Symptomatic stage (full-blown AIDS). In this third stage, the body's immune system begins to fail. The usual measurement for this stage is a CD4+ T cell count that drops below 200/?L. At this point the patient develops repeated opportunistic infections and may develop AIDS-related cancers.

As of the early 2000s, it takes an average of 11 years in younger adults for HIV infection to progress to AIDS; in seniors, the disease usually progresses faster.

Demographics

AIDS is considered the most destructive pandemic of the past century. As of 2008, the disease is estimated to have killed 25 million people around the world since it was first identified in 1981. An estimated 33.2 million people worldwide are presently living with the disease. According to the Centers for Disease Control and Prevention (CDC), an estimated 1,039,000 to 1,185,000 persons in the United States were living with HIV/AIDS at the end of 2003, with 24–27 percent undiagnosed and unaware that they are infected. Seniors are more likely than younger patients to be undiagnosed, with diagnostic evaluations in seniors often being delayed for as long as 10 months after the first symptoms of infection.

The demographics of HIV infection among the elderly have changed since the early days of the AIDS epidemic. In the mid-1980s, most cases of AIDS among seniors in the United States were the result of transfusions with contaminated blood. The introduction of effective screening tests for blood products has virtually eliminated this path of HIV transmission, however; as of 2008, almost all cases of AIDS in seniors are the result of sexual activity. In the United States, about 10 percent of all cases of AIDS occur in people over 50, and 3 percent in people over 60. About 35 percent of seniors who develop AIDS are homosexual or bisexual men; others are heterosexual men living in urban areas who engage in high-risk sex with prostitutes.

One reason that sexually active seniors are particularly at risk for HIV infection is that they are rarely concerned about contraception. Adults over 50 are five times more likely than younger people to have unprotected sex because they think of condoms as a method of birth control rather than a means of preventing disease transmission. In addition, older women have thinner and more fragile tissues lining the walls of the vagina; these tissues are more likely to be bruised or damaged during unprotected intercourse, making it easier for the virus to enter the underlying tissues. Several studies done in 2006 and 2007 have reported that older women are less likely than their younger counterparts to take precautions against HIV infection, in part because they are less sexually active than older men, and partly because they do not perceive themselves as being at risk for HIV infection.

According to the Merck Manual of Geriatrics, “Practically no prevention information on AIDS is targeted at elderly persons, although most elderly persons are sexually active.” According to statistics compiled by the Centers for Disease Control and Prevention, about 2100 men between the ages of 55 and 59 are diagnosed with HIV infection each year, and 800 over the age of 65. Since the epidemic began in 1981, 15,000 seniors over age 65 have been diagnosed with HIV in the United States.

Causes and symptoms

Causes

AIDS is caused by a retrovirus that contains an enzyme called reverse transcriptase. Reverse transcriptase converts viral RNA into a proviral DNA copy that becomes integrated into the DNA of the host cell. As the virus infects more cells, it gradually reduced the number of CD4+ T helper cells in the blood. These cells are the body's infection fighters. Counting the number of CD4+ T cells in a blood sample is one way to monitor the disease progress in someone infected with HIV.

Risk factors

Some seniors are at higher risk than others of HIV infection. In order to determine whether HIV testing should be a personal priority, the senior should use the following checklist of high-risk behaviors (for 1978 and later):

  • Shared needles for injecting drugs or steroids.
  • If a male, had unprotected sex with other males.
  • Had unprotected sex with someone known or suspected to be infected with HIV.
  • Had a blood transfusion between 1978 and 1985.
  • Had another sexually transmitted disease.
  • Had unprotected sex with anyone with any of the five previous risk factors.

Symptoms

The symptoms of HIV infection vary according to the progress of the infection. As mentioned above, about 30 percent of patients develop an acute syndrome resembling flu within a month of exposure to HIV. The patient typically has a fever, headache, swollen lymph nodes, and fatigue. The symptoms then disappear; however, the infected person is highly contagious in this early phase and can readily pass the virus on to others.

In the second phase, the virus may be silent, but more commonly it produces complications. Patients in this stage of infection may have the following symptoms:

  • Swelling of the lymph nodes that lasts three months or longer.
  • Fevers and night sweats.
  • Loss of energy.
  • Weight loss.
  • Frequent yeast infections of the vagina or mouth and throat. Yeast infections of the mouth are sometimes called thrush.
  • Skin rashes or flaky skin that does not go away.
  • Short-term memory loss. This symptom helps to explain why HIV infection in seniors is often misdiagnosed as early-stage Alzheimer' s.

In full-blown AIDS, the person develops one or more of the following opportunistic infections. Death usually results from one of these infections or from an AIDS-related cancer.

  • Lung infections: these include a type of pneumonia caused by an organism known as Pneumocystis jirovecii, a yeast-like fungus; and tuberculosis.
  • Mouth infections: these include oral candidiasis, or thrush.
  • Infections of the digestive tract: these include parasitic as well as bacterial infections, and are often marked by severe diarrhea.
  • Infections of the central nervous system: these include meningitis and toxoplasmosis. AIDS dementia complex (ADC), which is often misdiagnosed as Alzheimer's disease, is caused by destruction of brain tissue by toxins secreted by HIV. AIDS dementia complex affects between 10 and 20 percent of AIDS patients in the United States and is often the first symptom of full-blown AIDS. Like Alzheimer's, ADC is characterized by memory loss, inability to concentrate, loss of motor ability, poor balance, and mood changes.

AIDS-related cancers include Kaposi's sarcoma, a skin cancer occasionally found in older men who do not have HIV infection; and cervical cancers in women. AIDS patients are also at increased risk of developing Hodgkin's disease, Burkitt's lymphoma, and cancers of the anus or rectum.

Diagnosis

Physical examination and history

The patient's history is often the most important single diagnostic clue to HIV infection, particularly if he or she admits to unsafe sexual practices or intravenous drug use. If the doctor suspects HIV infection on the basis of the flu-like symptoms of acute retroviral syndrome, or if the patient requests HIV testing, the doctor will usually order appropriate blood or oral fluid tests.

Laboratory tests

HIV infection is usually diagnosed by a blood test, either an enzyme-linked immunosorbent assay (ELISA) test or a rapid screening test, and confirmed by a second blood test known as a Western blot test. A newer method of testing involves the collection of oral fluid from the patient's gums and teeth on a swab, but its results must also be confirmed by a Western blot test. In most cases an infected person's blood will develop antibodies to HIV within 1 to 3 months of being infected; however, a blood test may not yield accurate results within this window period, as it is known. The doctor may ask the senior to come back for a second blood test if the results of the first are inconclusive.

The doctor may also order a complete blood count and a stool test (if the patient is suspected of having intestinal parasites). If the patient appears to have an opportunistic infection of the nervous system, the doctor may order a lumbar puncture in order to test a sample of spinal fluid. In some cases the doctor may take a sample of nerve or muscle tissue for a biopsy.

Imaging tests

The doctor may order a chest x-ray if opportunistic infections of the lung are suspected.

Treatment

Post-exposure prophylaxis (PEP) Post-exposure prophylaxis (PEP) is a four- to eight-week course of antiretroviral drugs given to persons immediately after exposure (through rape, unprotected sex, or needlestick injuries) to HIV to prevent them from being infected by the virus. To be effective, PEP must be started within 48 hours of exposure. It has some unpleasant side effects, including severe nausea and headaches .

Antiretroviral therapy (ART)

Antiretroviral therapy (ART) refers to drugs or combinations of drugs given to AIDS patients to slow down the replication of HIV and to prevent it from developing resistance to treatment. The drugs are grouped into several categories according to the stage of the virus's life cycle that they inhibit. Some inhibit reverse transcription, others prevent the virus's DNA from being integrated into the DNA of the infected host cell, and still others prevent HIV from gaining entrance into its target cell.

In 1996, a new approach to ART known as highly active antiretroviral therapy or HAART was introduced. HAART is not one drug but a combination of various antiretroviral agents given to patients to prevent the virus from replicating and to discourage mutations of the virus. The drugs must be taken in combination because no medication by itself is able to suppress HIV for very long. One early problem with HAART was the complicated dosing schedules of the different drugs prescribed for an individual patient. To encourage adherence to treatment schedules (which must be at least 98 percent complete to protect the patient from developing a strain of the virus resistant to HAART), some pharmaceutical companies developed fixed-dose combinations—medications in which several antiretroviral drugs that are known to work well together are combined in a single pill.

Guidelines for offering HAART treatment to patients were published in the late 1990s because the drugs have so many adverse effects (including hair loss, muscle cramps and pains, kidney or liver failure, insomnia , inflammation of the pancreas, dizziness and mental confusion, headache, nausea and vomiting, and numbness in hands or feet) that many patients were not compliant with dosage schedules and developed drug-resistant mutations of the HIV virus. Recommendations for HAART have been revised several times by the U.S. Department of Health and Human Services. The following is the most recent set of standards, issued in October 2005:

  • All patients with history of an AIDS-defining illness or severe symptoms of HIV infection should receive antiretroviral therapy regardless of CD4+ T cell count.
  • Antiretroviral treatment is recommended for asymptomatic patients with less than 200 CD4+ T cells/µL.
  • Asymptomatic patients with CD4+ T cell counts of 201–350 cells/µL should be offered antiretroviral treatment.
  • For asymptomatic patients with CD4+ T cell of greater than 350 cells/µL and plasma HIV RNA greater than 100,000 copies/ml, most experienced
  • clinicians defer therapy but some clinicians may consider initiating antiretroviral treatment.
  • Antiretroviral therapy should be deferred for patients with CD4+ T cell counts of greater than 350 cells/µL and plasma HIV RNA less than 100,000 copies/ml.

Doctors who specialize in treating AIDS in seniors maintain that HAART should be started as early as possible and as aggressively as possible in older adults because they respond more slowly to treatment. As of 2008, however, relatively little is known about the most effective drug combinations for seniors. There are no official guidelines for antiretroviral treatment in the elderly, and seniors are rarely included in clinical trials of new AIDS drugs. In addition, the negative side effects of antiretroviral drugs are more pronounced in seniors, and interactions with drugs that the senior is taking for other conditions are common complications of treatment for AIDS.

Complementary and alternative (CAM) treatments

CAM treatments that have been recommended for AIDS patients include multivitamin therapy, acupuncture, yoga, massage therapy , and the use of relaxation techniques to improve mood and relieve depression . Some studies indicate that naturopathic treatments slow the progression of HIV infection even though they cannot cure it. Interestingly, a study published in 2007 reported that seniors with AIDS are just as likely to use complementary therapies since the introduction of HAART as they were before 1996. The study also reported that men who used CAM were more likely to be college-educated, to have contracted HIV through intravenous drug use rather than through sex with other men, and to be African American rather than Caucasian.

NCCAM announced plans in 2007 to conduct a three-year study of CAM therapies used by adults diagnosed with HIV. According to the center, between 47 and 74 percent of HIV-positive persons in the United States have used some type of CAM approach—most often to relieve the side effects of HAART as well as to improve overall well-being. The study is scheduled to run from 2009 through 2011.

Nutrition/Dietetic concerns

AIDS symptoms related to nutrition

Seniors with AIDS frequently develop symptoms that affect digestion and nutrition as a result of the disease itself combined with the side effects of antiretroviral drugs. One common side effect is nausea and vomiting, which makes the patient more susceptible to opportunistic infections as well as rapid weight loss . A second common development is lipodystrophy. Lipodystrophy is the medical term for the redistribution of body fat that sometimes occurs in patients with HIV infection as a result of HAART, genetic factors, the length of time a person has been HIV-positive, and the severity of the disease. It is not completely understood as of the early 2000s why antiretroviral drugs and other factors have this effect.

The patient may notice new deposits of fat at the back of the neck (sometimes called “buffalo humps”) and around the abdomen. Conversely, fat may be lost under the skin of the face, resulting in sunken cheeks, or lost under the skin of the buttocks, arms, or legs. Lipodystrophy is not necessarily associated with weight loss.

Still another nutritional symptom of AIDS is wasting. Wasting refers to rapid unintentional weight loss (usually defined as 5 percent of body weight over a period of 6 months) combined with changes in the composition of the senior's body tissue. Specifically, the patient is losing lean muscle tissue and replacing it with fat. The patient's outward appearance may not be a reliable guide to wasting, particularly if he or she also has lipodystrophy. Weight loss associated with wasting may result from nausea and vomiting related to opportunistic infections of the digestive tract as well as from reactions to medication.

Food safety issues

Food safety is an critical concern for seniors with HIV infection because their immune systems have difficulty fighting off food- or water-borne disease organisms. While most people can get food poisoning or parasitic infections of the digestive tract if they drink contaminated water or do not prepare food properly, older adults with HIV infection can get severely ill as a result of these diseases. Food-borne illnesses are also much more difficult to treat in persons with AIDS or HIV infection, and may lead to malabsorption syndrome, a condition in which the body cannot absorb and make use of needed nutrients in food. Basic dietary safeguards include the following:

  • Wash hands repeatedly in warm soapy water before and after preparing or eating food. Instant hand sanitizers should be used when away from home.
  • Cook all meats, fish, and poultry to the well-done stage; do not eat sushi, raw oysters, or raw meat in any form.
  • Do not use unpasteurized milk or dairy products.
  • Do not eat raw, soft-boiled, or “wet” scrambled eggs, or Caesar salad made with raw egg in the dressing. Hard-boiled or hard-scrambled eggs are safe.
  • Rinse all fruits and vegetables carefully in clean, safe water, and clean all cutting boards and knives that touch chicken and meat with soap and hot water before using these utensils with other food items.
  • Keep all refrigerated foods below 40°F; check expiration dates on food packaging.
  • Completely reheat leftovers before eating, and do not eat leftovers that have been stored in the refrigerator for longer than 3 days.
  • Do not drink water that comes directly from lakes, streams, rivers, or springs, and ask for drinks without ice in restaurants.

Treatments for wasting syndrome include increasing the senior's daily calorie intake and the use of appetite stimulants. In general, multivitamins, other dietary supplements, or herbal teas prepared by reliable manufacturers and approved by the patient's physician are useful complementary treatments for seniors with AIDS. According to NCCAM, high doses of vitamins are one of the most frequently used CAM treatments for counteracting the side effects of antiretroviral drugs.

Therapy

Therapy for AIDS consists of combination drug treatment (HAART in most cases), along with nutritional counseling, treatment of opportunistic infections, skin cancer, and dementia as they arise. Treatment also includes counseling regarding safe sex practices and supportive psychotherapy for the emotional depression that frequently affects seniors with AIDS.

Seniors with AIDS-related dementia usually re-quire placement in a long-term care facility; there is no effective treatment for this complication of AIDS.

Prognosis

Seniors generally have a worse prognosis than younger adults diagnosed with AIDS. The earlier stages of HIV infection progress more rapidly to AIDS in seniors, the initial CD4+ T cell counts are lower, and the survival period is shorter. Whereas 80 percent of younger adults survive for a year after being diagnosed with AIDS, only 40 percent of seniors survive that long.

QUESTIONS TO ASK YOUR DOCTOR

  • How can I lower my risk of HIV infection?
  • What are the side effects of HAART, and what can I do to minimize them?
  • What will happen if I miss a dose of my medication?
  • Is it safe to combine HAART with my other prescription drugs?
  • What dietary changes would you recommend?

The reasons for the poorer prognosis in older adults are not fully understood as of 2008. Various explanations include delayed diagnosis due to the fact that the early symptoms of HIV infection are easily confused with those of other diseases commonly found in older persons; inadequate treatment; the high rate of other diseases and disorders in the elderly that can further weaken the immune system; a lower rate of compliance with treatment regimens; and age-related changes in the immune system itself. It is thought that the immune system in older adults is less efficient in replacing T helper cells and so is more easily overwhelmed by HIV infection.

Prevention

The most effective preventive measure for AIDS is sexual abstinence, followed by sex within a monogamous relationship. Other measures include avoidance of intravenous drug use and avoidance of direct contact with the body fluids of persons who are HIV-positive.

KEY TERMS

Acute retroviral syndrome (ARS) —A syndrome that develops in about 30 percent of HIV patients within a few weeks of infection. ARS is characterized by nausea, vomiting, fever, headache, general tiredness, and muscle cramps.

CD4+ T cell —A type of helper cell in the human immune system that is attacked and infected by HIV. CD4 is a protein on the surface of these T cells that is used by the HIV virus to gain entry into the cells.

Enzyme-linked immunosorbent assay (ELISA) —A biochemical test used in immunology to detect the presence of antibody or antigen in a sample of blood serum. ELISA was the first screening test commonly used to detect HIV infection.

Highly active antiretroviral therapy (HAART) —An approach to HIV infection that consists of a combination of three or four separate drugs to treat the infection. It is not a cure for HIV infection but acts to slow the replication of the virus and discourage new mutations. HAART has a number of side effects that complicate compliance in AIDS patients.

Lipodystrophy —The medical term for redistribution of body fat in response to HAART, insulin injections in diabetics, or rare hereditary disorders.

Post-exposure prophylaxis (PEP) —A course of antiretroviral drugs given to people immediately following exposure to HIV infection from rape, unprotected sex, needlestick injuries, or sharing needles.

Retrovirus —A single-stranded virus that replicates by reverse transcription to produce DNA copies that are incorporated into the genome of infected cells. AIDS is caused by a retrovirus.

Seroconversion —The development of detectable specific antibodies in a patient's blood serum as a result of infection or immunization.

T-lymphocyte —A type of white blood cell, also knownas a T-helper cell, a Th cell, aneffector Tcell, or a CD4+ T cell, whose numbers in a blood sample can be used to monitor the progression of HIV infection.

Western blot —A procedure that uses electrical current passed through a gel containing a sample of tissue extract in order to break down the proteins in the sample and detect the presence of antibodies for a specific disease. The Western blot method is used in HIV testing to confirm the results of an initial ELISA test.

Caregiver concerns

A caregiver for a senior with AIDS should be concerned with the following:

  • Complete compliance with the senior's HAART regimen. Failure to take the medications exactly as directed can lead to resistant forms of HIV and eventual treatment failure. A handout for patients on how to take antiretroviral medications is available on the American Academy of Family Physicians website at http://www.aafp.org/afp/20030815/689ph.html.
  • Nausea, vomiting, and weight loss, or signs of lipodystrophy or wasting syndrome. The doctor may recommend a consultation with a professional dietitian.
  • Signs of dementia. As noted earlier, AIDS-related dementia in seniors is often misdiagnosed as Alzheimer's disease.
  • Signs of drug interactions between the senior's antiretroviral therapy and medications he or she may be taking for other diseases.
  • Signs of upper respiratory infections, particularly pneumonia or thrush.
  • Skin disorders, including changes in the skin that may indicate cancer.

Resources

BOOKS

Beers, Mark H., M. D., and Thomas V. Jones, MD. Merck Manual of Geriatrics, 3rd ed., Chapter 134, “Human Immunodeficiency Virus Infection.” Whitehouse Station, NJ: Merck, 2005.

Klausner, Jeffrey D., and Edward W. Hook, III, eds. Current Diagnosis and Treatment of Sexually Transmitted Diseases. New York: McGraw-Hill Medical, 2007.

Lee, Sharon Dian. HIV and Aging. New York: Informa Healthcare USA, 2008.

Pelletier, Kenneth R., MD. The Best Alternative Medicine, Part II, “CAM Therapies for Specific Conditions: AIDS.” New York: Simon & Schuster, 2002.

PERIODICALS

Akers, A., L. Bernstein, S. Henderson, et al. “Factors Associated with Lack of Interest in HIV Testing in Older At-Risk Women.” Journal of Women's Health (Larchmont) 16 (July-August 2007): 842–858.

Branson, B. M. “State of the Art for Diagnosis of HIV Infection.” Clinical Infectious Diseases 45 (December 15, 2007): S221–225.

Josephs, J. S., J. A. Fleishman, P. Gaist, et al. “Use of Complementary and Alternative Medicines among a Multistate, Multisite Cohort of People Living with HIV/AIDS.” HIV Medicine 8 (July 2007): 200–305.

Lindau, S. T., L. P. Schumm, E. O. Laumann, et al. “A Study of Sexuality and Health among Older Adults in the United States.” New England Journal of Medicine 357 (August 23, 2007): 762–774.

Manfredi, Roberto, and Francesco Chiodo. “A Case-Control Study of Virological and Immunological Effects of Highly Active Antiretroviral Therapy in HIV-infected Patients with Advanced Age.” AIDS 14 (July 7, 2000): 1475–1477.

Perlmutter, Barbara L., Jordan B. Glaser, and Samwel O. Oyugi. “How to Recognize and Treat Acute HIV Syndrome.” American Family Physician 60 (August 1999): 535–546.

“Position of the American Dietetic Association and Dietitians of Canada: Nutrition Intervention in the Care of Persons with Human Immunodeficiency Virus Infection.” Journal of the American Dietetic Association 104 (September 2004): 1425–1441.

Tichy, A. M., and M. L. Talashek. “Older Women: Sexually Transmitted Diseases and Acquired Immunodeficiency Syndrome.” Nursing Clinics of North America 27 (December 1992): 937–949.

Weerasuriya, N., and J. Snape. “Oesophageal Candidiasis in Elderly Patients: Risk Factors, Prevention and Management.” Drugs and Aging 25 (February 2008):119–130.

OTHER

Centers for Disease Control and Prevention (CDC). Deciding If and When to Be Tested, posted January 22, 2007. http://www.cdc.gov/hiv/topics/testing/resources/qa/be_tested.htm [cited February 15, 2008].

Centers for Disease Control and Prevention (CDC). HIV Partner Counseling and Referral Services: Guidance. Washington, DC: U.S. Department of Health and Human Services, 1998.

Centers for Disease Control and Prevention (CDC). Voluntary HIV Counseling and Testing: Facts, Issues and Answers. Washington, DC: U.S. Department of Health and Human Services, 1998. Available online in PDF format at http://cdcnpin.org/brochures/Testing.pdf [cited February 16, 2008].

Chan-Tack, Kirk M. “Early Symptomatic HIV Infection.” eMedicine, February 20, 2007. http://www.emedicine.com/med/topic86.htm [cited March 9, 2008].

Dubin, Jeff. “HIV Infection and AIDS.” eMedicine, February 5, 2007. http://www.emedicine.com/emerg/topic253.htm [cited February 14, 2008].

U.S. Food and Drug Administration (FDA). Eating Defensively: Food Safety Advice for Persons with AIDS. Available online at http://www.cfsan.fda.gov/̃dms/aidseat.html [updated 2005; cited March 9, 2008].

National Center for Complementary and Alternative Medicine (NCCAM). Project Concept Review: CAM Approaches in the Management of HIV Disease and Its Complications. Bethesda, MD: NCCAM, 2007. Available online at http://nccam.nih.gov/research/concepts/consider/hivncam.htm [cited March 9, 2008].

ORGANIZATIONS

American Academy of HIV Medicine, 1705 DeSales Street NW, Suite 700, Washington, DC, 20036, (202) 659-0699, (202) 659-0976, [email protected], http://www.aahivm.org/index.php?option=com_frontpage&Itemid=1.

Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA, 30333, (404) 498-1515, (800) 311-3435, http://www.cdc.gov/.

Centers for Disease Control and Prevention National Prevention Information Network (CDC NPIN), P.O. Box 6003, Rockville, MD, 20849, (404) 679-3860, (800) 458-5231, (888) 282-7681, [email protected], http://www.cdcnpin.org/scripts/about/index.asp.

Food and Drug Administration (FDA), 5600 Fishers Lane, Rockville, MD, 20857, (888) 463-6332, http://www.fda.gov/default.htm.

HIV InSite, University of California San Francisco, Center for HIV Information, 4150 Clement Street, Box 111V, San Francisco, CA, 94121, (415) 379 5547, [email protected] hivinsite.ucsf.edu, http://hivinsite.ucsf.edu/InSite.

National Center for Complementary and Alternative Medicine (NCCAM), 9000 Rockville Pike, Bethesda, MD, 20892, (301) 519-3153, (888) 644-6226, (866) 464-3616, [email protected], http://nccam.nih.gov.

Rebecca J. Frey Ph.D.

views updated

Acquired Immunodeficiency Syndrome (AIDS)


Acquired Immunodeficiency Syndrome (AIDS) is caused by the human immunodeficiency virus (HIV), which destroys the cells in the human body that combat infections. Although recent medical advances have caused a shift from the mindset of a terminal disease to one of a chronic, manageable condition in some areas of the world, this new approach brings challenges of its own, as the disease is eventually fatal (Ferri et. al 1997). HIV has brought about a global epidemic far more extensive than what was predicted even a decade ago. The issue of HIV/AIDS is not only relevant to medical documentation, but is complex and highly politically charged, affecting all communities regardless of race, age, or sexual orientation (Ginsberg 1995). At the end of the year 2000, it was estimated that there were 36.1 million adults and children living with HIV/AIDS, the vast majority of whom live in the developing world, with more than twenty-five million living in the continent of Africa ("Global Summary of the HIV/AIDS Epidemic, 2000" 2001).


History

The epidemic began in the late 1970s and early 1980s in sub-Saharan Africa, Latin America, the Caribbean, Western Europe, North America, Australia, and New Zealand. In the late 1980s, the epidemic continued to spread to North Africa and the Middle East, South and Southeast Asia, East Asia, and the Pacific. Only in the late 1990s did the epidemic spread significantly to Eastern Europe and Central Asia. (See Table 1 for a summary of HIV/AIDS statistics and features, including the primary mode(s) of transmission in each region.) Since 1981, the AIDS pandemic has brought sexually transmitted diseases to the center of medical

TABLE 1
HIV/AIDS statistics and features
regionmain mode(s) of transmission* for adults # living with hiv/aidsepidemic started
*hetero (heterosexual transmission), idu (transmission through intravenous drug use), msm (sexual transmission among men who have sex with men).
#the proportion of adults (15 to 49 years of age) living with hiv/aids.
australia & new zealandmsmlate 1970s – early 1980s
caribbeanhetero, msmlate 1970s – early 1980s
east asia & pacificidu, hetero, msmlate 1980s
eastern europe & central asiaiduearly 1990s
latin americamsm, idu, heterolate 1970s – early 1980s
north africa & middle easthetero, idulate 1980s
north americamsm, idu, heterolate 1970s – early 1980s
south & south-east asiahetero, idulate 1980s
sub-saharan africaheterolate 1970s – early 1980s

and social consciousness. Indeed, "not since the world-wide pandemic of swine influenza in 1918 have we faced a public health emergency of such tragic magnitude" (Brandt 1988, p. 151).

In response to this mysterious ailment, articles began to appear in newspapers and magazines in the United States that described an illness unofficially identified as gay-related immunodeficiency (GRID). As early as 1982, however, it became clear to the researchers at the Centers for Disease Control (CDC), that the disease was not exclusively a gay syndrome. Other groups began to get the disease: heterosexuals from sub-Saharan Africa, Haitians, prostitutes, and women who had sex with bisexual males (Tebble 1986).

The human T-cell lymphotropic virus (HTLVIII) was isolated as the retrovirus responsible for causing AIDS in 1984 (Getzel 1992; Levenson 1996). A retrovirus is a type of virus that replicates mutant strains, and then infects other cells (Gant 1998). "The virus, called HTLV-III by the Americans and LAV by the French—would eventually be designated as HIV" (Bethel 1995, p. 69). HIV-I (the most common type found worldwide) and HIV-II (found mostly in West Africa), both responsible for AIDS, are rapid replicators. The newer strains of HIV that were identified in the late 1990s are stronger and more resistant to medications.


Modes of Transmission

HIV is transmitted only through the intimate exchange of body fluids, specifically blood, semen, vaginal fluid, and mother's milk (Dane and Miller 1990). HIV is sometimes passed perinatally from mother to fetus, or through breastfeeding (Mulvi-hill 1996). HIV levels in the bloodstream are typically highest when a person is first infected and again in the late stages of the illness. High-risk behaviors include unprotected anal and vaginal intercourse (without condom) and intravenous drug use. Before blood screening began in 1986, the virus was also being contracted from transfusions and blood-clotting agents.

Testing and Diagnosis

One year after the isolation of HIV, the ELISA (enzyme-linked immunosorbent assay) test was developed, allowing detection of HIV antibodies well before the onset of any clinical manifestations, creating an opportunity for preventive therapy against opportunistic infections (Bellutta 1995). The required pre- and post-test counseling for the ELISA tests has been shown to help people to make informed decisions, cope better with their potential health condition, lead more positive lives, and prevent further transmission of HIV. Because the number of false positives is high, a positive ELISA test must be confirmed by a more specific test, the Western blot, which detects specific anti-bodies to a particular pathogen (Gant 1998). In many countries, home tests were approved in mid-1990s, and the oral collection (OraSure) for HIV antibody test was approved by the Food and Drug Administration (FDA) in the United States in 1996. These tests are not very reliable, and support such as pre- and post-test counseling is not available ("Fact Sheet 1 HIV/AIDS: The Infection" 2000).

The advent of HIV testing brought with it the need for guidelines surrounding the confidentiality of test results and anonymity of the individual during the testing process to protect that person against social stigmatization and economic exploitation. These measures are also intended to encourage widespread testing, so that medical care and support services can be instituted early in the process.

HIV attacks and destroys CD4 T-lymphocytes, which assist in the regulation of the entire immune system. CD-4 lymphocytes, also called CD-4 cells, T4cells, and CD-4 lymphocytes, are a type of blood cell important to the immune system. The loss of these cells reduces the system's ability to fight infection, increasing the risk of opportunistic infections, or infections that can take hold because a person's immune system is weak (Gant 1998). AIDS can be described as a continuum that begins with infection by the HIV virus leading to decreasing numbers of CD-4 cells and eventual progress to opportunistic diseases (Bellutta 1995).


Symptoms

HIV ranges from asymptomatic infection to severe forms of the disease (Aronstein and Thompson 1998). There is no dormant phase of the HIV infection. Rather, the body and the virus are locked in a pitched battle from the beginning. Every day the viral intruder produces a billion copies of itself, all intent on the destruction of CD-4 cells (Gorman 1996). With immune deficiency, the HIV-infected person becomes susceptible to opportunistic organisms that normally would be harmless (Aronstein and Thompson 1998).

Kaposi's sarcoma is a malignant tumor affecting the skin and mucous membranes and is usually characterized by the formation of pink to reddish-brown or bluish patches. In general, these tumors are quite rare, slow-growing, vascular in nature, and most commonly affect elderly men of Mediterranean descent. In the early AIDS cases, however, the tumors affected young white males in the United States and were found to grow and disseminate rapidly. Overwhelming infection and respiratory failure due to pneumocystis carinii pneumonia (PCP), a form of pneumonia caused by a microorganism that attacks the inner fibrous tissues of the lungs, were the leading causes of death in early AIDS cases (Bellutta 1995).

HIV-infected persons often experience acute symptoms including night sweats, sore throat, headache, fever, muscular pains, thrush, wasting, and rashes. It is estimated that more than half of the people diagnosed with AIDS at some time will display central nervous system dysfunction resulting from HIV infiltration of brain structures. The growing crisis of AIDS-related cognitive impairment ranges from mild cognitive disturbance to moderate and severe AIDS dementia complex (ADC).

Neuropsychological symptoms are typically more pronounced in the end stage of the disease; however, decreased concentration, memory loss, and confusion may be the first symptoms of AIDS.


Treatment

Researchers persist in their attempts to develop effective medical treatments to reduce the suffering of those who are HIV-infected or seriously ill with AIDS. Encouraging early treatment is crucial for persons that test HIV positive (Levenson 1996). HIV treatments include two components: first, prophylactic drugs to prevent and treat opportunistic infections, and, second, combination or three-drug combinations (also known as drug cocktails) to directly reduce replication of the virus (Linsk and Keigher 1997). Where available, the antiretroviral drug combinations (protease inhibitor combined with two or more Reverse Transcriptase inhibitors) require strict adherence to a complex drug regimen. The potential benefits and risks of the combinations are great. Many people taking drug combinations have been found to have reduced viral load to levels below the detection limits of current viral load tests, therefore appearing to be no longer HIV positive. However, the virus can easily become resistant to the medications if the regimen is not followed, often causing the viral load to increase. Many people infected with HIV are finding that eating a healthful diet, getting sufficient rest, and drinking little alcohol increase their level of functioning.

HIV/AIDS prevention through education, as well as safe-sex information, distribution of condoms, and needle exchange programs worldwide have greatly decreased the transmission of new HIV cases in many parts of the world since 1990. In addition, officials from many health organizations, including the World Health Organization (WHO), and governments from various countries, have been collaborating in an effort to address the urgent need for an HIV vaccine. Since 1991, these constituents have worked to prepare for HIV vaccine efficacy trials. In February of 1999, Thailand became the first developing nation to announce a three-year, Phase III vaccine field trial, AIDSVAX. A Phase III trial is done to determine if a vaccine is effective in protecting against infection or disease and is an important step in the evaluation process leading to licensure.


Psychosocial Issues

In the initial years of the epidemic, the complex clinical treatment dynamics, negative public attitudes, and limited personal and community resources available to people with AIDS challenged the advocacy and discharge-planning skills of many professionals (Mantell, Shulman, Belmont, and Spivak 1989). Repeated exposure to death, homophobia, negative attitudes about addictive lifestyles, antisocial behaviors, and fear of AIDS contagion have added stress to professionals employed in the health arena and supporting services (Wade, Stein, and Beckerman 1995).

Partially because disadvantaged populations are disproportionately affected by HIV/AIDS, there is often a stigma attached to the diagnosis (Diaz and Kelly 1991; Reamer 1993). People within the United States have been victims of hate crimes due to their HIV positive status. Within many countries in Africa, people have been stoned to death, or disowned when an HIV positive status was disclosed ("Fact Sheet 6 HIV/AIDS: Fear, Stigma, and Isolation" 2000). Fear and prejudice have been an integral part of this epidemic since its inception, often exacerbating already difficult situations for those dealing with the diagnosis of HIV/AIDS (Ryan and Rowe 1988). Responses to this difficult reality include depression, claiming illness is something other than HIV/AIDS, withdrawal from loved ones and work environments, and even suicide (Ellenberg 1998).


Global Implications

The challenges of HIV vary enormously from place to place, depending on how far and fast the virus is spreading, whether those infected have started to fall ill or die in large numbers, and what sort of access they have to medical care. In all parts of the world except sub-Saharan Africa, more men than women are infected with HIV and dying of AIDS. Men's behavior—often influenced by harmful cultural beliefs about masculinity—makes them the prime casualties of the epidemic. Male behavior also contributes to HIV infections in women, who often have less power to determine where, when, and how sex takes place ("Global Summary of the HI/AIDS Epidemic" 2001). Men's enormous potential to make a difference when it comes to curbing HIV transmission, caring for infected family members, and looking after orphans and other survivors of the epidemic has been noted in many countries.

As the number of children orphaned by HIV/AIDS rises, some calls have been heard for an increase in institutional care for children. This solution is impracticably expensive. In Ethiopia, for example, keeping a child in an orphanage costs about U.S. $500 a year, more than three times the national income per person. One solution developed by church groups in Zimbabwe is to recruit community members to visit orphans in the homes where they live—either with foster parents, grandparents or other relatives, or in child-headed households. Households caring for orphans are provided with clothing, blankets, school fees, seeds, and fertilizer as necessary, and communities contribute to activities such as farming communal fields and generating income to support the program. This community-driven approach to orphan support has been reproduced all over Zimbabwe, and replicas are now sprouting up in other African countries ("Global Summary of the HIV/AIDS Epidemic, 2000" 2001).

Internationally, a campaign by AIDS activists succeeded in 2000 in getting drug companies to lower prices for the antiretroviral medications. But even at prices 90 percent lower than in the United States, drugs are still beyond the reach of most Africans. There is a debate among those working on AIDS in Africa and elsewhere about whether the current emphasis on drugs is taking the spotlight off prevention, where many feel it should be. Apart from the staggering costs of drugs, world health leaders say huge sums of money are needed just for basic AIDS prevention and care in Africa and other developing nations ("Confronting AIDS" 2001).

UNAIDS and WHO now estimate that the number of people living with HIV or AIDS at the end of the year 2000 stands at 36.1 million, 50 percent higher than what the WHO's Global Programme on AIDS projected in 1991 ("Global Summary of the HIV/AIDS Epidemic, 2000" 2001). The unique situation in various countries and parts of the world will be presented in order to catch a glimpse of the diverse face of HIV/AIDS in the early twenty-first century. In each area, access to health care and medication, HIV transmission, and political responses will be considered.


Botswana. The first AIDS cases in Botswana were reported in 1985. An estimated 36 percent of adults were HIV positive as of 2000. The highest HIV prevalence rate is among twenty to thirty-nine year olds. An estimated 300,000 adults and 26,000 children under age five are living with HIV/AIDS. The mean age of death due to AIDS in Botswana is twenty-five in females and thirty-five in males, the reproductive and economically productive years.

Unlike many other African countries, Botswana has a strong and developed infrastructure that provides people with such social services as education and health care. The government, as well as many companies, are trying to provide antiretrovirals to all who need them, regardless of their ability to pay. Well-supplied hospitals and adequate foreign reserves make it easier for Botswana than for other African countries to provide the drugs. But even here, where the annual per capita income is $3,700 a year (high for Africa), many people remain poor. In the next ten years AIDS will slice 20 percent off the government budget, erode development gains, and bring about a 13 percent reduction in the income of the poorest households ("Global AIDS Program Countries" 2001).

The hope of treatment encourages people to be tested, and testing is considered crucial for prevention. Even as efforts to treat people get underway, prevention remains the highest priority, including visits to local bars to show people how to prevent HIV using male and female condoms and going to schools to keep the next generation HIV-free.


Brazil. HIV began to spread in Brazil in the 1980s. At of the end of the year 2000, slightly more than 196,000 cases of AIDS had been reported in Brazil, the largest number in South America. Brazil is unique among the Latin American countries in that it provides those people with HIV infection antiretroviral therapy free of charge if they meet the national medical guidelines for treatment.

An estimated 12,898 pregnant women had HIV infection in 1998, while 536,920 people between the ages of fifteen and twenty-nine were infected with HIV. Between the years 1978 and 1999, 29,929 children were orphaned in Brazil due to AIDS. Although rates of AIDS are decreasing among men who have sex with men and injection drug users, the rate of heterosexual transmission of AIDS is increasing. In many municipalities, especially along the coast, the ratio of AIDS between men and women is approaching 1:1 ("Global AIDS Program Countries" 2001).


South Africa. The HIV/AIDS epidemic started in sub-Saharan Africa in the late 1970s and early 1980s. Half of all HIV positive people in the nine southern African countries hardest hit by the pandemic live in South Africa. The government estimates that 4.2 million persons, and 19.9 percent of the adult population, are infected with HIV, and by 2010 adult HIV prevalence could reach 25 percent, similar to infection rates in neighboring Zimbabwe and Botswana. In 1998 South Africa had approximately 100,000 AIDS orphans, and by 2008, 1.6 million children will have been orphaned by AIDS ("Global AIDS Program Countries" 2001).

Reasons cited for high rates of HIV/AIDS in South Africa are the realities of migrant labor, high prevalence of sexually transmitted disease, and presence of multiple strains of the disease. Exacerbating factors include a society in denial about an overwhelming epidemic that is ravaging the lives and bodies of many persons within a context of poverty and a thriving commercial sex work industry.

Families are especially hard hit by HIV/AIDS in South Africa. One in five pregnant women in South African clinics is HIV positive. Studies have shown that treating pregnant African women with the drug AZT significantly reduced the risk that they would transmit the virus to their babies. However, if these women then breastfed their infants, the risks of transmission rebounded, making it more urgent than ever to find acceptable alternatives to breastfeeding among infected African women. The AIDS virus accounts for most pediatric cases in hospitals. The worst is yet to come because most of the infected have not yet developed AIDS symptoms, and many still feed an infection spiral that is creating about 1,700 new cases every day.Thailand. Thailand has experienced a rapidly escalating and severe HIV epidemic since 1988. Among the sixty million inhabitants of Thailand, as many as 800,000 people are currently believed to be living with HIV. Despite innovative and persistent prevention efforts, HIV continues to spread rapidly, particularly among Thailand's population of injection drug users (IDUs). Methadone treatment, education, counseling on HIV prevention, and easy access to sterile needles have helped to slow the epidemic. Yet, among IDUs in Bangkok, 6 percent continue to become infected each year.

As part of the Thai National Plan for HIV vaccine research, the Bangkok Metropolitan Administration is leading the three-year collaborative research trial to evaluate the ability of AIDSVAX to prevent HIV infection among uninfected IDUs in Bangkok, Thailand. For people infected with HIV, the Thai government and health officials feel very strongly that treatment should follow the protocols that they have established for their country. Therefore, the triple drug therapies currently being used elsewhere are not considered feasible for use in Thailand, not only because of cost constraints, but also because of issues related to the complexity of the regimen, the necessary follow-up and monitoring of patients, and tolerance to the therapies.


United States. In the early 1980s, a number of unexplainable phenomena began to surface across the United States. As the incidents of pneumocystic pneumonia and Kaposi's sarcoma were reported to the Center for Disease Control, a pattern began to emerge. The CDC first published a report reflecting these observations in June of 1981, identifying all of the people demonstrating these symptoms as gay men (Black 1985). In the absence of services in established medical centers and social agencies, many gay men and lesbians joined with activists to establish community-based AIDS service organizations to meet the needs of people affected by HIV. The Names Project Quilt, or AIDS Quilt, has been an important mechanism for people within the United States to recognize the lives of those who have died of HIV/AIDS. The quilt was first displayed in Washington, DC, in 1987, and then in its entirety for the last time in October of 1996, with more than 30,000 panels.

In the United States, as of December 2000, 774,467 AIDS cases had been reported including 640,022 cases among men and 134,441 among women. The main modes of transmission for adults living with HIV/AIDS were men having sex with men, intravenous drug users, and heterosexual transmission. In the United States HIV and AIDS have disproportionately affected the most disadvantaged and stigmatized groups in American society (Barbour 1994). Analyzed by race, 330,160 AIDS cases have been reported among whites, 292,522 among blacks, and 141,694 among Hispanics.

In early 1998, AIDS deaths in the United States dropped by 47 percent. "In recent years, the rate of decline for both cases and deaths began to slow, and in 1999, the annual number of AIDS cases appears to be leveling, while the decline in AIDS deaths has slowed considerably" ("A Glance at the HIV Epidemic" 2001, p. 3). Overall, HIV prevalence rose risen slightly, mainly because antiretroviral therapy is keeping HIV positive people alive longer. Thousands of infections are still occurring through unsafe sex between men. In this era in which few young gay men have seen friends die of AIDS, and some mistakenly view antiretrovirals as a cure, there is growing complacency about the HIV risk, judging from reports of increased sexual risk behavior among this population.


Conclusion

The family is greatly affected in all cases of HIV/AIDS, regardless of where the person might live. Issues such as safe sex practices, planning for care of children during parents' illness and after death, dealing with prejudices and unmet expectations within the family unit, coming out as a homosexual, admitting to intravenous drug use, or to sexual activity with multiple partners, are often on the forefront during this difficult time. Until a vaccine is approved and widely disseminated, people must avoid risky behaviors in order to curb the spread of this devastating disease. One of the primary issues is to support extended family members who are taking in children orphaned by AIDS, while grieving the great loss of loved ones.

See also:Chronic Illness; Death and Dying; Dementia; Family Planning; Hospice; Sexuality; Sexuality Education; Sexually Transmitted Diseases; Stress


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"Fact Sheet 6 HIV/AIDS: Fear, Stigma and Isolation." (2000). World Health Organization. Available from http://www-int/whosis/statistics/factsheets-hiv-nurses/fact-sheet-6/index.html.

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HOPE HASLAM STRAUGHAN

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AIDS Tests

Definition

AIDS tests, short for acquired immunodeficiency syndrome tests, cover a number of different procedures used in the diagnosis and treatment of HIV-infected patients. Tests that measure antibodies to the human immunodeficiency virus (HIV) are called AIDS serology tests. Serology is the branch of immunology that deals with the identification and measurement of antibodies in serum. Presence of antibodies indicates the presence of disease or immunity to disease. Serum is the normally clear light yellow noncellular portion of blood that forms after the sample is allowed to clot. Some AIDS tests measure HIV antigens or nucleic acid rather than antibodies produced in response to HIV infection. AIDS tests evaluate the presence of HIV in blood serum, and the effects of HIV infection on the patient's immune system.

Purpose

AIDS serology tests have several uses. Some AIDS tests are used to diagnose patients or confirm a diagnosis; others are used to measure the progression of the disease or the effectiveness of specific treatment regimens. Some AIDS tests are used to screen blood donations for safe use in transfusions.

In order to understand the different purposes of the blood tests used for AIDS patients, it is helpful to understand how HIV infection affects the immune system. HIV is a retrovirus that enters the blood stream of a new host in the following ways:

  • sexual contact, including oral and anal intercourse
  • entry of HIV infected body fluids (such as blood or urine) through a cut or break in the skin
  • transmission during pregnancy
  • using or being pricked by a needle that had previously been used by or on an infected person
  • transfusion of infected blood products

A retrovirus is a virus that contains two identical strands of RNA and a unique enzyme called reverse transcriptase that converts the viral RNA to DNA within the host cell. Another viral enzyme called integrase inserts this proviral DNA into the host cell DNA. Other viral proteins control the process of transcription, which forms RNA copies of the inserted DNA, production of structural viral proteins, assembly of immature virus particles, maturation, and release (budding) from the host cell. The entire process takes 12-24 hours.

The primary host cell for HIV is the T helper cell. The HIV envelope contains a glycoprotein called gp120 that binds to a surface molecule on the T helper cell called CD4. Other types of lymphocytes that lack the CD4 molecule are not infected. In addition to T helper cells, HIV can infect phagocytic cells (macrophages, monocytes, and dendritic cells), which serve as reservoirs and spread the virus throughout the body. The virus can also infect certain tissue cells such as neurons, which in part accounts for some of the underlying pathology of HIV disease.

HIV disease begins as a flu-like illness two to six weeks after infection which subsides without treatment. Antibodies to the viral envelope appear eight to 12 weeks after infection. Most patients enter a phase of clinical latency, which on average lasts eight to 10 years. This is followed by gradual loss of CD4 positive lymphocytes (T helper cells). T helper cells produce a substance called interleukin-2 (IL-2). IL-2 stimulates other cells (T cells and B cells) in the human immune system to respond to infections. Without the IL-2, the immune response collapses and patients become susceptible to a wide range of infections. Depletion of T helper cells signals the onset of opportunistic infections, malignancy, dementia, and a constellation of other diseases associated with AIDS.

Precautions

There are no medical restrictions on administering AIDS tests. Most tests are performed on blood, but a screening test using urine is available. Health care professionals should always follow standard precautions recommended by the Centers for Disease Control (CDC) to reduce the possibility of accidental needlestick injury or exposure to the patient's blood and body fluids. This includes wearing latex gloves, washing hands before and following venipuncture, and using disposable needles and safety devices.

Description

Diagnostic tests

Diagnostic blood tests for AIDS are usually given to persons in high-risk populations, pregnant females, health care and public service workers who have been exposed to HIV, or those who have symptoms associated with AIDS. The condition of testing positive for HIV antibody in the blood is called seroconversion, and persons who are HIV-positive are called seroconverters.

AIDS tests used to diagnose infection fall into two categories, screening tests and confirmatory tests. It is possible to diagnose HIV infection by isolating the virus from the blood. However, viral culture is expensive, not widely available, and time consuming. Screening tests detect the presence of antibodies to several HIV antigens. These tests are inexpensive, widely available, and accurate in detecting 99.9% of HIV infections. However, approximately 0.2% of persons without HIV infection will test positive. In order to eliminate these false positives, persons should be tested in duplicate and positive results followed by a confirmatory test.

ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA). This test is the most commonly used method to screen blood for transfusions as well as to diagnose patients. An ELISA test for HIV works by attaching two or more HIV antigens to a plastic well or beads. A sample of the patient's blood serum is added and incubated. If antibodies to HIV antigens are present, they will bind to the tube, or bead. After washing to remove excess proteins, an anti-human immunoglobulin conjugated to an enzyme is added. After incubation, excess antibody is washed away and a chemical called a substrate is added. The enzyme reacts with the substrate to form a colored product that indicates a positive test.

The latest generation of ELISA tests are 99.5% sensitive to HIV. Occasionally, the ELISA test will be positive for a patient without symptoms of AIDS from a low-risk group. Because this result is likely to be a false positive, the ELISA must be repeated on the same sample of the patient's blood. If the second ELISA is positive, the result should be confirmed by the Western blot or other confirmatory test.

WESTERN BLOT (IMMUNOBLOT). The Western blot or immunoblot test is used as a reference procedure to confirm the diagnosis of HIV infection. In Western blot testing, HIV antigens of different size are purified from HIV cultures and separated from each other by the process of electrophoresis. (In electrophoresis, protein molecules are suspended in a gel and separated by applying an electric current through the gel.) The HIV antigens are transferred to a nylon membrane or nitrocellulose filter. The patient's serum is added to this, and if antibodies are present they will bind to the corresponding viral antigens. The membrane is washed and anti-human immunoglobulin conjugated to an enzyme is added. After washing again, the color-developing substrate is added, which causes colored bands to appear where the serum antibodies are attached to the membrane. Western blots can detect antibodies to several HIV antigens, but results must be interpreted with caution because antibodies produced against other viruses may cross-react. A test is considered positive when antibodies are seen against antigens from at least two of the three major HIV antigens (p24, gp41, and gp120/160).

When used in combination with ELISA testing, Western blot testing is 99.9% specific. It can, however, yield false negatives in patients with very early HIV infection and in those infected by HIV-2. In some patients the Western blot yields indeterminate results.

IMMUNOFLUORESCENCE ASSAY (IFA). This method is sometimes used to confirm ELISA results instead of the Western blot test. An IFA test detects the presence of HIV antibody in a sample of the patient's serum by incubating the serum with H9 cells infected with HIV virus. The cells are grown in tissue culture and transferred to glass slides, which are frozen. After incubating with the patient's serum, the slide is washed to remove the serum and fluorescein-conjugated antihuman immunoglobulin is added. After incubation, the unbound conjugate is removed by washing the slide. The slide is examined using a fluorescent microscope. The conjugate causes the HIV-infected cells coated with antibody to have a green fluorescence. This test can detect antibody of the IgM class that is produced within seven to 10 days after infection.

RADIOIMMUNOPRECIPITATION ASSAY (RIPA). A third confirmatory HIV testing method is the radio-immunoprecipitation assay (RIPA). This test also uses H9 lymphocytes infected with HIV. The cells are grown in tissue culture media containing radioactive methionine. This causes the viral antigens to be radioactive. A lysate is prepared from the cultured cells and incubated with serum. If antibodies are present in the serum they will bind to the radioactive viral antigens. These radioactive immune complexes are isolated onto sepharose beads coated with Staphylococcal protein-A. The beads are precipitated and tested for radioactivity, the presence of which indicates a positive test.

VIRAL LOAD TESTS. Tests for viral load measure the amount of virus in the blood either by quantifying nucleic acid or p24 antigen (p24 antigen capture assay). They may be used as confirmatory tests for HIV infection, but are more often used to determine the progression of HIV disease to AIDS and to determine the onset of drug resistance, both of which are signaled by an increase in the concentration of circulating viruses. The nucleic acid based tests for viral load include the reverse transcriptase-polymerase chain reaction (RT-PCR) test, branched DNA signal amplification method (bDNA), and the nucleic acid sequence-based amplification method (NASBA). DNA amplification methods can detect as little as 50 copies of viral RNA per mL of plasma and can detect infection during the "window phase," when antibody levels are too low to produce a positive test result. In the RT-PCR assay, guanidinum isothocyanate is added to the patient's serum or plasma. The RNA is precipitated with isopropanol, and the RNA is resuspended and incubated in a medium containing reverse transcriptase, heat stable DNA polymerase (Taq polymerase), oligonuclotide primers tagged with biotin, and nucleotide triphosphates. The reverse transcriptase produces a double stranded DNA copy of the viral RNA. This DNA copy serves as the template for the polymerase chain reaction. Heat is used to separate the target DNA strand, a process known as denaturation. The temperature is lowered and the primers bind to the target sequence, a process called annealing. Heat stable DNA polymerase fills in the sequence by adding nucleotide triphosphates to the 3' end of the primer, a process called extention. This makes a new copy of the double stranded DNA. The cycle is repeated, making use of the newly synthesized DNA molecule as a template. If the process is repeated 30 times there will be over one billion copies of the target DNA. The amplified DNA, called amplicons, are denatured into single strands and are detected by means of an enzyme-conjugated DNA probe which hybridizes to the amplicons.

P24 ANTIGEN CAPTURE ASSAY. The p24 antigen capture assay is also used to measure viral load. Found in the viral core of HIV, p24 is a protein that can be measured by enzyme immunoassay. Generally, p24 is detected early in infection (before antibody production) but then falls to undetectable levels shortly after antibody production. The p24 assay is useful in detecting HIV infection before seroconversion, and for this reason it is used along with ELISA when testing donor blood for HIV. A return to detectable levels occurs when the virus becomes activated. Therefore, the test is used to identify patients who have become unresponsive to antiviral therapy and to indicate progression to AIDS. The test is not a useful screening test for HIV, since only about 20-30% of patients are positive in the early stages of HIV infection. Beads coated with monoclonal antibodies against p24 antigen are mixed with serum and incubated. After washing to remove unbound serum proteins, the beads are mixed with a second antibody to p24 derived from a rabbit. The beads are washed again, and an enzyme-conjugated anti-rabbit immunoglobulin is added. A final wash step is performed and substrate is added. The amount of color formed is proportional to the p24 antigen level of the serum.

KEY TERMS

Antibody— A protein in the blood that identifies and helps remove disease organisms or their toxins. Antibodies are secreted by B cells. AIDS diagnostic tests work by demonstrating the presence of HIV antibody in the patient's blood.

Antigen— Any substance that stimulates the body to produce antibodies.

B cell A type of white blood cell derived from bone marrow. B cells are sometimes called B lymphocytes. They secrete antibody and have a number of other complex functions within the human immune system.

CD4— A type of protein molecule in human blood that is present on the surface of 65% of human T cells. CD4 is a receptor for the HIV virus. When the HIV virus infects cells with CD4 surface proteins, it depletes the number of T cells, B cells, natural killer cells, and monocytes in the patient's blood. Most of the damage to an AIDS patient's immune system is done by the virus' destruction of CD4+ lymphocytes. CD4 is sometimes called the T4 antigen.

Complete blood count (CBC)— A routine analysis performed on a sample of blood taken from the patient's vein with a needle and vacuum tube. The measurements taken in a CBC include a white blood cell count, a red blood cell count, the red cell distribution width, the hematocrit (ratio of the volume of the red blood cells to the blood volume), and the amount of hemoglobin (the blood protein that carries oxygen).

Electrophoresis— A method of separating complex protein molecules suspended in a gel by running an electric current through the gel.

Enzyme-linked immunosorbent assay (ELISA)— A diagnostic blood test used to screen patients for AIDS or other viruses. The patient's blood is mixed with antigen attached to a plastic tube or bead surface. A sample of the patient's blood serum is added, and excess proteins are removed. A second antibody coupled to an enzyme is added, followed by a chemical that will cause a color reaction that can be measured by a special instrument.

Human immunodeficiency virus (HIV)— Atransmissible retrovirus that causes AIDS in humans. Two forms of HIV are now recognized: HIV-1, which causes most cases of AIDS in Europe, North and South America, and most parts of Africa; and HIV-2, which is chiefly found in West African patients. HIV-2, discovered in 1986, appears to be less virulent than HIV-1, but may also have a longer latency period.

Immunofluorescent assay (IFA)— A blood test sometimes used to confirm ELISA results instead of using the Western blotting. In an IFA test, HIV antigen is mixed with a fluorescent compound and then with a sample of the patient's blood. If HIV antibody is present, the mixture will fluoresce when examined under ultraviolet light.

Lymphocyte— A type of white blood cell that is important in the formation of antibodies. Doctors can monitor the health of AIDS patients by measuring the number or proportion of certain types of lymphocytes in the patient's blood.

Macrophage— A large white blood cell, found primarily in the bloodstream and connective tissue, that helps the body fight off infections by ingesting the disease organism. HIV can infect and kill macrophages.

Monocyte— A large white blood cell that is formed in the bone marrow and spleen. About 4% of the white blood cells in normal adults are monocytes.

Opportunistic infection— An infection that develops only when a person's immune system is weakened, as happens to AIDS patients.

Polymerase chain reaction (PCR)— A test performed to evaluate false-negative results to the ELISA and Western blot tests. In PCR testing, numerous copies of a gene are made by separating the two strands of DNA containing the gene segment, marking its location, using DNA polymerase to make a copy, and then continuously replicating the copies. The amplification of gene sequences that are associated with HIV allows for detection of the virus by this method.

Retrovirus— A virus that contains a unique enzyme called reverse transcriptase that allows it to replicate within new host cells.

Seroconversion— The change from HIV-negative to HIV-positive status during blood testing. Persons who are HIV-positive are called seroconverters.

Serology— The analysis of the contents and properties of blood serum.

Serum— The part of human blood that remains liquid when blood cells form a clot. Human blood serum is clear light yellow in color.

T cells— Lymphocytes that originate in the thymus gland. T cells regulate the immune system's response to infections, including HIV. CD4 lymphocytes are a subset of T lymphocytes.

Viral load test— A new blood test for monitoring the speed of HIV replication in AIDS patients. The viral load test is based on PCR techniques and supplements the CD4+ cell count tests.

Western blot— A technique that is used to confirm ELISA results. HIV antigen is purified by electrophoresis and attached by blotting to a nylon or nitrocellulose filter. The patient's serum is reacted against the filter, followed by treatment with developing chemicals that allow HIV antibody to show up as a colored patch or blot. If the patient is HIV-positive, there will be stripes at specific locations for two or more viral proteins. A negative result is blank.

WBC differential— A white blood cell count in which the technician classifies the different white blood cells by type as well as calculating the number of each type. A WBC differential is necessary to calculate the absolute CD4+ lymphocyte count.

BLOOD DONOR TESTING. Blood donated for transfusion is tested for HIV-1 and HIV-2 by ELISA, p24 antigen capture, and RT-PCR. For the latter, donor samples are pooled and tested for the presence of virus. This process detects the rare donors units that are negative for anti-HIV but potentially infective. This process has reduced the window phase from 22 days (ELISA alone) down to 11 days. It is estimated that the risk of receiving a transfusion of HIV positive blood in the United States is less than 1 in 562,500 when ELISA and p24 antigen testing are both used.

In 1999, the U.S. Food and Drug Administration (FDA) approved an HIV home testing kit. The kit contains multiple components, including material for specimen collection, a mailing envelope to send the specimen to a laboratory for analysis, and provides pre- and post-test counseling. It uses a finger prick process for blood collection. The results are obtained by the purchaser through a toll-free telephone number using a personal identification number (PIN). Post-test counseling is provided over the telephone by a licensed counselor. The only kit approved by the FDA as of 2001 was the Home Access test system.

Prognostic tests

In addition to tests for viral antigens and antibodies, other blood tests are needed to evaluate and manage patients with HIV disease. The most important of these is the CD4 positive lymphocyte count. This test measures the number of T helper cells in the blood. A CD4 count of less than 200/microL or 14% of the total lymphocyte count in a person who is HIV positive constitutes a diagnosis of AIDS. A falling CD4 positive lymphocyte count parallels a rise in viral replication and correlates with both a risk of opportunistic infection and drug resistance in patients receiving highly active antiviral therapy (HAART).

It is important for doctors treating AIDS patients to measure the CD4 positive lymphocyte count on a regular basis. Experts consulted by the U.S. Public Health Service recommend the following frequency of serum testing based on the patient's CD4+ level:

  • CD4+ count more than 600 cells/microL: Every six months.
  • CD4+ count between 200-600 cells/microL: Every three months.
  • CD4+ count less than 200 cells/microL: Every three months.

When the CD4+ count falls below 200 cells/microL, the doctor will put the patient on a medication regimen to protect him or her against opportunistic infections.

BETA2-MICROGLOBULIN (β2M). Beta2-microglobulin is a protein found on the surface of all human cells with a nucleus. It is released into the blood when a cell dies. Although rising blood levels of β2M are found in patients with cancer and other serious diseases, a rising β2M blood level can be used to measure the progression of AIDS.

GENOTYPIC DRUG RESISTANCE TEST. Genotypic testing can help determine whether specific gene mutations, common in people with HIV, are causing drug resistance and drug failure. The test looks for specific genetic mutations within the virus that are known to cause resistance to anti-viral drugs. For example the drug 3TC, also known as lamivudine (Epivir), is not effective against strains of HIV that have a mutation at a particular position, known as M184V, in their reverse transcriptase enzyme. If the genotypic resistance test shows a mutation at position M184V, it is likely that person is resistant to 3TC and not likely to respond to treatment. Genotypic tests are only useful when the patient is already taking antiviral medication, and the viral load is greater than 1,000 copies per mL of plasma. The cost of the viral drug resistance testing is usually between $300 and $500, and is usually not covered by insurance plans, including Medicare.

PHENOTYPIC DRUG RESISTANCE TESTING. Phenotypic testing directly measures the in vitro sensitivity of a patient's HIV strains to particular drugs and drug combinations. The test measures the concentration of a drug required to inhibit viral replication by 50% and 90%. This is the same method used by researchers to determine whether a drug might be effective against HIV before using it in human clinical trials. Phenotypic testing is a more direct measurement of resistance than genotypic testing. Unlike genotypic testing, phenotypic testing does not require a high viral load, but it is recommended that persons already be taking antiretroviral drugs. The cost is between $700 and $900 and is usually not covered by insurance plans, including Medicare.

AIDS serology in children

Children born to HIV-infected mothers may acquire the infection through the mother's placenta or during the birth process. Public health experts recommend the testing and monitoring of all children born to mothers with HIV. Diagnostic testing in children older than 18 months is similar to adult testing, with ELISA screening confirmed by Western blot. Younger infants can be diagnosed by direct culture of the HIV virus, PCR testing, and p24 antigen testing. These techniques allow a pediatrician to identify 50% of infected children at or near birth, and 95% of cases in infants three to six months of age.

Preparation

In addition to diagnostic testing for HIV infection, many laboratory tests are important to the proper management and treatment of patients with HIV disease and AIDS. These include the complete blood count (CBC), cultures and serological tests for opportunistic infections, Pap smear for cervical cancer, imaging studies, nerve conduction studies, and tests for nutritional status.

Aftercare

Preparation and aftercare are important parts of AIDS diagnostic testing. Doctors are now advised to take the patient's emotional, social, economic, and other circumstances into account and to provide counseling before and after testing. Patients are generally better able to cope with the results if the doctor has spent some time with them before the blood test explaining the basic facts about HIV infection and testing. Many doctors now offer this type of informational counseling before performing the tests.

Complications

The risks of AIDS testing are primarily related to disclosure of the patient's HIV status rather than to any physical risks connected with blood testing. Some patients are better prepared to cope with a positive diagnosis than others, depending on their age, sex, health, resources, belief system, and similar factors.

Results

Normal results for ELISA, Western blot, IFA, and PCR testing are negative for HIV antibody.

Normal results for CD4+ lymphocytes: 500-1200/microL, 34-67% of all lymphocytes.

The following abnormal results of AIDS tests indicate progression of the disease:

  • Percentage of CD4 positive lymphocytes: less than 14% of all lymphocytes.
  • CD4+ lymphocyte count: less than 200 cells/microL.
  • Viral load test: Levels more than 5000 copies/mL.

Health care team roles

Nurses and phlebotomists (workers who draw blood) are usually the health care professional that draw the blood for AIDS tests. However, it is the physician that recommends specific treatment and prescribes needed medication. HIV tests are performed by clinical laboratory scientists, CLS(NCA) or medical technologists, MT(ASCP). It is often the role of a trained counselor to tell the patient the test results. Regardless of the results, nurses, health care educators, and counselors often are responsible for educating the patient about safe sex practices and risk factors for contracting HIV, along with the possible need for periodic repeat testing.

Resources

BOOKS

Connolly, Sean. AIDS. Chicago: Heinemann Library, 2003.

Murphy, Robert L., and John P. Flaherty. Contemporary Diagnosis and Management of HIV/AIDS Infections. Newtown, PA: Handbooks in Health Care, 2003.

Watstein, Sarah, and Stephen E. Stratton. The Encyclopedia of HIV and AIDS. New York: Facts On File, 2003.

PERIODICALS

Carter, Zakia Munirah "Know Your Status: The Latest News on HIV Testing Could Save Your Life." Essence 35 (December 2004): 99-101.

MacLean, R. "Stigma Against People Infected With HIV Poses a Major Barrier to Testing." International Family Planning Perspectives 30 (June 2004): 103.

"The Ideal Versus The Best; AIDS Testing." The Economist 370 (February 2004): 76.

ORGANIZATIONS

Centers for Disease Control and Prevention (CDC). 1600 Clifton Rd., Atlanta, GA 30337. (404)639-3311. 〈http://www.cdc.gov/〉.

National Association of People with Aids. 1413 K St.N.W., Washington, DC 20005-3442. (202)898-0414. 〈http://www.nipwa.org.htm〉.

National Institute of Health. Office of Aids Research. (301)496-0357. 〈http://www.nih.gov/od/oar/index.htm〉.