AIDS: Origin of the Modern Pandemic

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AIDS: Origin of the Modern Pandemic


History and Policy Response

Impacts and Issues

Primary Source Connection



The world has reached the twenty-fifth year of the modern AIDS pandemic, which has been acknowledged by the United Nations (UN) to be among the deadliest epidemics in human history. AIDS has killed 25 million people and infected an estimated additional 40 million people since 1981, many of whom will die of the disease without effective treatment.

History and Policy Response

Little is yet known about the incidence and prevalence of AIDS prior to the first reported cases in the United States in the early 1980s. In the 1970s, the HIV virus was unknown and, given its latency period with which clinicians are now familiar, transmission was not associated with signs or symptoms significant enough to be noticed. A small number of case reports of AIDS and medical archaeological studies have uncovered human infections with HIV prior to 1970. Scientists have pieced together evidence suggesting that AIDS originated in Africa, but the precise location of the pandemic's origin remains unknown. AIDS is thought to have begun in the primordial forests of West Africa when a virus harbored in the blood of a monkey or a chimpanzee made the genetic leap to humans, possibly after a hunter was infected by a bite. HIV was discovered by researchers in a blood sample collected in 1959 from a man in Kinshasa, Congo. Further genetic analysis of the man's blood indicated that the HIV infection was caused by a single virus in the late 1940s or early 1950s. Thus, it appears that the earliest human infections went unnoticed on a continent where people routinely die from tropical diseases with unusual manifestations.

Analyses of medical records in African countries have shown that there had been striking increases in opportunistic infections now known to be AIDS-related during the late 1970s and early 1980s. These included “slim” disease in Zaire (late 1970s) and in Uganda and Tanzania (early 1980s); esophageal candidiasis in Rwanda (from 1983); aggressive Kaposi's sarcoma in Zaire (early 1980s) and in Zambia and Uganda (1982 and 1983); and crypotococcal meningitis in Zaire (late 1970s to early 1980s). Research suggests that although isolated cases of AIDS may have occurred in Africa earlier, it was probably rare until the late 1970s and early 1980s. Studies further suggest that demographic groups and the routes of disease transmission have been largely similar in Africa and Western nations, implicating sexual activity among young and middle-aged people, blood transfusions, vertical transmission from mother to infant, and frequent exposure to unsterilized needles as the most likely means of transmitting AIDS.

Thus, available data suggest that the modern AIDS pandemic started in the mid- to late-1970s. By 1980, HIV had spread to North America, South America, Europe, and Australia. During this early stage of the epidemic, the transmission of the virus was unhindered by awareness of the disease or any preventive action, and approximately 100,000–300,000 persons are estimated to have contracted the infection.

In March 1981, however, a few cases of an aggressive form of Kaposi's sarcoma (KS) were documented among young gay men in New York. This development caused concern because KS was known as a rare, relatively benign cancer that tended to occur in elderly people with immune system impairment. Simultaneously, there was an increase in California and New York in the incidence of Pneumocystis carinii pneumonia (PCP), an unusual lung infection. The Centers for Disease Control and Prevention (CDC) noticed this increase in April in the course of monitoring prescriptions that were dispensed for rare drugs and detected a spike in requests for pentamine to treat PCP. In June 1981, the CDC published a report outlining the occurrence of five cases of PCP without identifiable cause in Los Angeles. This report marks the beginning of a more general awareness of AIDS, and, shortly thereafter, the CDC formed a task force to investigate a syndrome that they called Kaposi's sarcoma and Opportunistic Infections (KSOI).

Speculation among scientists soon centered on whether this apparently new disease was a consequence of the widespread recreational use of amyl nitrate for sexual stimulation among gay men, or the possibility of immune system overload in this population due to exposure to repeated sexually transmitted infections such as cytomegalovirus (CMV). CDC officials issued statements indicating that the disease appeared to be limited to gay men and that there was no apparent risk of spreading the disease through contagion.


ANTIRETROVIRAL DRUGS: Antiretroviral (ARV) drugs prevent the reproduction of a type of virus called a retrovirus. The human immunodefiency virus (HIV), which causes acquired immune deficiency syndrome (AIDS, also cited as acquired immune deficiency syndrome), is a retrovirus. These ARV drugs are therefore used to treat HIV infections. These medicines cannot prevent or cure HIV infection, but they help to keep the virus in check.

IMMUNODEFICIENCY: In immunodeficiency disorders, part of the body's immune system is missing or defective, thus impairing the body's ability to fight infections. As a result, the person with an immunodeficiency disorder will have frequent infections that are generally more severe and last longer than usual.

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.

By 1982, however, AIDS was reported among injection drug users, and disease patterns among a group of gay men in California appeared to support the notion that the disease was sexually transmitted. Later in the year, cases appeared among citizens of Haiti and among persons with hemophilia, a blood disorder that is treated with infusions of blood clotting factors. After the spreading disease shed its exclusive association with gay men, the CDC characterized the disease as acquired immuno-deficiency syndrome (AIDS, also cited as acquired immune deficiency syndrome). This terminology for the ailment was chosen because the immune system impairment that was its hallmark was acquired rather than inherited as in other known immunodeficiencies. AIDS was labeled a syndrome because it was associated with a group of diseases rather than a single disease. By the end of 1982, cases of AIDS began to appear in European countries, and a wasting syndrome dubbed “slim” was reported in Uganda, which was soon linked to AIDS. By the end of the year, over 600 cases had been reported in the United States.

In 1983, physicians diagnosed the first cases of AIDS among women with no other apparent risk factors, indicating that the disease could be transmitted by heterosexual contact. In view of the evidence that AIDS was an infection that could be transmitted via blood and blood products, the CDC mounted a concerted effort to discover an infectious agent responsible for causing the disease. In May, doctors at the Institute Pasteur in France reported the isolation of a new virus, which they suggested might be the cause of AIDS. Although scant notice was taken of this announcement when it was made, a sample of the virus was sent to the CDC. Several months later, the virus was named lymphadenopathy-associated virus or LAV, and a sample of LAV was sent to the National Cancer Institute (NCI). In the meantime, public anxiety over the means of AIDS transmission, viewed by some people as potentially spread through casual contact due to its incidence among children, continued to grow, giving rise to increasingly numerous panic-driven and sometimes cruel interactions involving people either with AIDS or seen as at risk for AIDS. These incidents included evictions of persons with AIDS from housing; families and loved ones abandoning their relatives or partners with AIDS; and use of surgical masks during police work with individuals suspected of having AIDS. The CDC soon issued information that confirmed that there was no evidence for casual transmission and explained the possibility of bloodborne transmission of infection of AIDS from mothers to children.

By 1984, it became clear that the AIDS epidemic had been established in central Africa among populations that were not at risk from homosexuality, drug use, blood transfusion, or hemophilia. In Africa, cases often had an aggressive and often fatal form of Kaposi's sarcoma, which had up to this point been endemic to the region, but had been easily treatable. The main risk factor in Africa for AIDS appeared to be heterosexual contact. American and European scientists began to focus on the African epidemic, particularly because it appeared more likely to spread throughout the world due to its predominantly heterosexual mode of transmission than the epidemic in America and Europe.

The Institute Pasteur continued to claim that LAV was the cause of AIDS, but a related virus called human t-cell leukemia virus III (HTLV-III) was discovered by a research team in San Francisco. Investigators began to suspect that these viruses were identical. By the end of 1984, the CDC had reported nearly 8,000 AIDS cases and 3,500 deaths from the disease.

In 1985, the U.S. Food and Drug Administration confirmed that LAV and HTLV-III were identical, and that the virus was indeed the cause of AIDS. The FDA additionally ordered testing of the national blood supply and required that anyone testing positive for the virus would not be allowed to donate blood. Now that the cause of AIDS could be detected, public bewilderment over AIDS transmission gave way to concern over the dissemination and use of information about HTLV-III/LAV infection. The gay community voiced fears of stigmatization of persons found to carry the virus, believing the information would be misused by employers and insurance companies to exclude infected individuals. Incidents of cruelty and prejudice directed toward AIDS victims and perceived risk groups continued to mount, though Haitians were removed from the list of high-risk groups in view of new understanding of heterosexual and injection drug transmission risks. The year 1985 ended with more than 20,000 reported U.S. AIDS cases, with over 15,000 cases reported in other nations.

The International Committee on the Taxonomy of Viruses ruled in May 1986 that the LAV and HTLV-III virus names should be dropped in favor of Human Immunodeficiency Virus (HIV). During that year, the Director of the WHO announced that some 10 million people worldwide could already have been infected with HIV by June 1986. The true scope and devastation of the disease had begun to be apparent to the scientific community.


Within an eight-month period in 1980–1981, five young men were hospitalized in the Los Angeles area with a rare, severe form of pneumonia caused by the pathogen (disease-causing microorganism) Pneumocystis carinii. In reporting the outbreak to the Centers for Disease Control and Prevention (CDC), physician Michael S. Gottlieb and his colleagues first documented in medical literature the disease that was to become known as AIDS. The report jarred physicians in New York and San Francisco, who noticed a handful of similar cases occurring at about the same time. In another unusual occurrence, eight young men in the New York area with Kaposi's sarcoma had recently died. Kaposi's sarcoma is a form of skin cancer that was usually seen mainly in elderly persons. Suspecting a new or emerging disease among young men, the Centers for Disease Control and Prevention (CDC) formed a task force to investigate the outbreaks. Gottlieb was an assistant professor of medicine at the University of California at Los Angeles (UCLA) in 1981 when he submitted the featured report as its lead author. In 1985, Gottlieb co-founded the American Foundation for AIDS Research.


In initial reports to the CDC, all of the young men with both Pneumocystis pneumonia and Kaposi's sarcoma were actively homosexual, and early on, the task force considered the disease likely to be confined to the community of homosexual males. By the end of 1981, it became clear that that the newly recognized disease affected other population groups, as the first cases of Pneumocystis pneumonia were reported in drug users who injected their drugs. It also became clear that the disease was not confined to the United States when similar cases were found within a year in the United Kingdom, Haiti, and in Uganda, where the disease was already known as “slim.”

Impacts and Issues

As of early 2007, officials at UNAIDS, a United Nations organization tasked with uniting efforts to treat and eliminate HIV, estimated that another 50 million people could die from AIDS in India and China alone by the year 2025. In Africa, where research indicates that the epidemic likely began, AIDS will have killed 100 million people by that time if trends continue. Although antiretroviral medications have begun to lower expected death rates, AIDS could still kill 40 million additional Africans by 2025. To date, all vaccine development programs have failed. Prevention programs focused on changing sexual and drug-use behaviors have had mixed success across regions and across cultural and political divides.

Primary Source Connection

The primary source “Many Blood Banks Deny Request of Hemophiliacs” demonstrates the confusion and fears surrounding the earliest days of the AIDS epidemic in the United States, when the cause of the disease was known, but erroneously linked only to specific groups.

The author/creator, The Associated Press, is a worldwide and multiple Pulitzer Prize winning news agency based in New York.

Editor's note: As set forth in the introduction, the perspective of time and accumulation of subsequent information can often make assertions contained in primary sources—even if based upon the best information available at the time written—subsequently misleading or wrong. Readers should be mindful that primary sources often contain information later proven to be false, or contain viewpoints and terms unacceptable to future generations. It is important to view primary sources within the historical and social context existing at the time of creation.


The advent of AIDS (Acquired Immunity Deficiency Syndrome) in early 1981 stunned the scientific community, as many researchers at that time viewed the world to be on the brink of eliminating infectious disease. Victims of AIDS most often die from opportunistic infections that take hold of the body because the immune system is severely impaired. AIDS is caused by the Human Immune Deficiency Virus (HIV). HIV belongs to a class of viruses known as retroviruses. These viruses are known as RNA viruses, because they have RNA (ribonucleic acid) as their basic genetic material instead of DNA (deoxyribonucleic acid).

Following its discovery and spread in Western nations, the urgency of combating AIDS significantly altered the distribution of research funding in the biomedical sciences—including increased funding for research on retroviruses. Whether such shifts in funding were insufficient (i.e., more research money should have been spent sooner) or to the overall detriment of world health—because it sometime shifted money from research on diseases that kill more people worldwide—is often a contentious scientific, political, and ethical issue.

See AlsoAIDS (Acquired Immunodeficiency Syndrome); Antiviral Drugs; Bloodborne Pathogens; Developing Nations and Drug Delivery; Epidemiology; Opportunistic Infection; Public Health and Infectious Disease; Sexually Transmitted Diseases.



Mayer, Kenneth H., and H.F. Pizer. The AIDS Pandemic: Impact on Science and Society. San Diego: Academic Press, 2004.


Hymes, K.B., J.B. Greene, A. Marcus, et al. “Kaposi's Sarcoma in Homosexual Men: A Report of Eight Cases.” Lancet 2 (1981): 598–600.

Gottlieb, M.S., et al. “Pneumocystis Pneumonia—Los Angeles” Morbidity and Mortality Weekly Report (June 5, 1981): (30) 21, 1–3. Available online at <> (accessed April 21, 2007).

Web Sites

Kaiser Family Foundation. “The Global HIV-AIDS Timeline.” <> (accessed February 19, 2007).

Centers for Disease Control and Prevention. “Milestones in the U.S. HIV Epidemic.” <> (accessed March 25, 2007).

Kenneth T. LaPensee