AIDS

AIDS, or Acquired Immune Deficiency Syndrome, is a disease caused by a virus that disables the immune system. The virus enters the body through the bloodstream, duplicates itself rapidly, and eventually destroys the body's immune system. This leaves the victim susceptible to other infectious diseases that usually prove fatal.

AIDS is caused by the Human Immunodeficiency Virus (HIV) that was first isolated in 1983. Before 1981, AIDS was unknown, and many health professionals believed that infectious diseases were a thing of the past in developed countries. However, following the discovery in late 1980 of several young homosexual men who had developed rare forms of pneumonia and cancer, health officials in the United States realized they had discovered a new infectious disease that enters the bloodstream and destroys the immune system. From these beginnings, the worldwide estimates of the number of people infected with AIDS has reached 30,000,000. More than 12,000,000 people have already died from AIDS since the beginnings of this worldwide epidemic, and although the number of infected individuals has stabilized in developed countries, the number of AIDS cases has exploded in many African countries.

HOW AIDS SPREADS

AIDS is obviously a contagious disease for which there is no cure. It is spread by a virus and transmitted by entering the bloodstream. This means that AIDS cannot be spread by the type of casual contact that usually takes place between family members and friends. HIV must somehow enter the bloodstream to infect a person, and the most common way for this to happen is through some form of intimate sexual contact that allows bodily fluids from one person to enter that of another. This is what occurs during any type of sexual intercourse or sexual penetration of a person's body. Another way is for an intravenous drug user to share a needle with another person. HIV has also been transmitted to an unborn child by its infected mother, and until programs for blood screening were created, HIV had also been transmitted by blood transfusions.

AIDS TAKES OVER THE IMMUNE SYSTEM

AIDS is an especially difficult disease because, unlike other forms of infections, it attacks the very system that we use to defend ourselves against outside invasions. The HIV virus is a ribonucleic acid (RNA) virus like many other viruses, such as the flu, the common cold, and measles. However, HIV is also a retrovirus, which makes it quite different and deadly. Viruses contain their own forms of deoxyribonucleic acid (DNA) and RNA (their own genetic code), but a retrovirus contains a special enzyme that enables it to put its own DNA into the DNA of the cell it invades. A retrovirus can then use the infected cell's machinery to continuously reproduce itself and make more and more copies of the retrovirus.

ROBERT CHARLES GALLO

American virologist (a person specializing in the study of viruses) Robert Gallo (1937– ) is credited as the codiscoverer of the human immunodeficiency virus (HIV). Gallo also established that HIV causes acquired immunodeficiency syndrome, or AIDS (a disease caused by a virus that disables the immune system), and developed the blood test for detecting HIV, which is still the main tool in diagnosing the disease. Moreover, Gallo's blood test for HIV has made the blood supply safe.

Robert Gallo was born in Waterbury, Connecticut, and grew up in the same house that his immigrant grandparents bought after they came to the United States from Italy. His father had a welding business, but the dominant theme of young Gallo's family life was the illness and death of his only sibling, his sister Judy. His sister died of childhood leukemia, and this disease brought Gallo into regular contact with the nonfamily member who most influenced his life, Doctor Marcus Cox. During his senior year in high school, an injury forced Gallo off the basketball team and got him thinking about his future. He began to spend time with Cox, and by the time Gallo was ready for college, he knew he wanted a career in biomedical research. Gallo majored in biology at Providence College in Rhode Island, and went on to earn a medical degree from Jefferson Medical College in Philadelphia in 1963.

In 1965 Gallo joined the National Institutes of Health (NIH) to do cancer research, and in 1971 he was appointed head of a new Tumor Cell Biology laboratory at NIH. There he studied retroviruses, which are types of viruses that possess the ability to penetrate other cells and to splice their own genetic material into the genes of their hosts, eventually taking over all of the invaded cell's reproductive functions. This research led him to discover the first human cancer virus.

When AIDS began to be recognized in the United States in early 1981 as a new and terrible disease, it was Gallo's pioneering work in the field of human retrovirology that led him to be one of the first scientists to hypothesize that the disease was caused by a virus. In 1982, the National Cancer Institute formed an AIDS task force with Gallo as its head. By 1984, Gallo's team was able to establish that the Human Immunodeficiency Virus caused AIDS, and it developed a blood test for detecting the virus. It was then that a controversy developed which would involve Gallo for the next decade. The controversy began when a French colleague who had earlier and independently discovered the same virus sent Gallo a sample. The result involved legal disputes and hearings, accusations, findings, and reversals of opinions on which scientists had actually discovered the virus first. Overall, it is now thought that the virus sent to Gallo from France may have contaminated the blood samples that he held, making for a mistake but not misconduct. Today, Gallo has survived and overcome the allegations and is the director of the Institute of Human Virology in Baltimore, Maryland. There, Gallo continues his pioneering work in the field of human retroviruses. Gallo has received many honors, including the distinction of being the most referenced scientist in the world between 1980 and 1990.

Once inside the body and reproducing, HIV goes to work by attacking the very type of cells that the body automatically uses to fight invaders like viruses. It mainly attacks what are called the T-4 white blood cells and eventually causes their number to dramatically decrease. As these important disease-fighting cells are killed off, the body's ability to resist infection is severely impaired, and AIDS patients become more susceptible to what are called "opportunistic" infections such as pneumonia, tuberculosis, and rare forms of cancer.

PHASES OF AIDS

The disease typically goes through three major phases. During the first stage, the individual experiences general flu-like symptoms and remains relatively healthy while the immune system keeps fighting back. However, once the immune system begins to weaken (which may take several years), the next stage includes symptoms like swollen glands, severe fatigue, cough, diarrhea, and night sweats, as well as persistent infections like thrush and herpes. Only in the final stage, which is what is technically called AIDS, does the patient develop the serious infections or tumors that will eventually prove fatal. AIDS is a terribly wasting disease and its victims are usually reduced to human skeletons as their lungs and brains are also destroyed.

Continued and heavily funded research has not yet found a cure for AIDS, although researchers have discovered drug combinations that effectively prolong the period before full-blown AIDS begins. As with any virus however, HIV has already mutated and developed strains that are resistant to some of these drugs. Research on the origins of AIDS suggests that the virus may be a mutant of a strain that is known to infect the African green monkey, an animal that often comes in contact with humans in West Africa.

To date, information and educational campaigns throughout the world have been effective in making people aware that prevention is, for now, the only sure weapon against AIDS. However, sexual behavior and drug-related activities are not always conducted with common sense in mind. It is especially important to always practice safe sex by using a condom

(a rubber sheath that is worn over the penis to prevent the exchange of bodily fluids) and not to share intravenous drug needles. Even with widespread awareness, an estimated 6,000,000 new infections occur every year.

[See alsoImmune System; Virus ]