Understanding AIDS

Acquired Immune Deficiency Syndrome, or AIDS, was first reported in mid-1981 in the United States; it is believed to have originated in Sub-Saharan Africa. The human immunodeficiency virus (HIV) that causes AIDS was identified in 1983, and by 1985 tests to detect the virus were available. The credit for discovering the AIDS virus is jointly shared by Dr. Robert Gallo, a researcher at the National Cancer Institute, and Luc Montagnier of the Pasteur Institute, France.

Although the first reported cases involved homosexual men in Los Angeles who were infected through sexual contact, the principal mode of transmission throughout the world is through the exchange of bodily fluids during heterosexual intercourse. According to the World Health Organization, extensive spread of HIV appears to have begun in the late 1970s and early 1980s among men and women with multiple sexual partners in East and Central Africa and among homosexual and bisexual men in certain urban areas of the Americas, Australasia, and Western Europe.

In addition to sexual contact, AIDS has been spread by intravenous drug users sharing infected hypodermic needles. The virus can also be passed on through transfused blood or its components. It may also be transmitted from infected mother to infant before, during, or shortly after birth.

Two major types of HIV have been recognized, HIV-l and HIV-2. HIV-l is the dominant type worldwide. HIV-2 is found principally in West Africa but cases have been reported from East Africa, Europe, Asia, and Latin America. There are at least ten different genetic subtypes of HIV-l, but their biological and epidemiological significance is unclear at present. Both HIV-l and HIV-2 are transmitted in the same ways.

A fatal and incurable disease caused by the human immunodeficiency virus (HIV), AIDS attacks and destroys the immune system, gradually leaving the individual defenseless against illnesses that lead to death. These illnesses are referred to as “opportunistic” infections or diseases: in AIDS patients the most common are Pneumocystis carinii pneumonia (PCP), a parasitic infection of the lungs; and a type of cancer known as Kaposi's sarcoma (KS). Other opportunistic infections include unusually severe infections with yeast, cytomegalovirus, herpes virus, and parasites such as Toxoplasma or Cryptosporidia. Milder infections with these organisms do not suggest immune deficiencies. Symptoms of full-blown AIDS include a persistent cough, fever, and difficulty in breathing. Multiple purplish blotches and bumps on the skin may indicate Kaposi's sarcoma. The virus can also cause brain damage.

People infected with the virus can have a wide range of symptoms—from none to mild to severe. At least a fourth to a half of those infected will develop AIDS within four to ten years. Many experts think the percentage will be much higher.

With no cure at present, prudence could save thousands of people who have yet to be exposed to the virus. Use of condoms lessens the possibility of transmission as does the elimination of sharing hypodermic needles. The fate of many will depend less on science than on the ability of large numbers of human beings to change their behavior in the face of growing danger.

New drugs and tests have given researchers renewed optimism in treating AIDS. As of July 1996, three dozen preventive HIV vaccines were being tested in small-scale clinical trials around the world. In the summer of 1998, the first AIDS vaccine trials began in the United States. Five thousand volunteers are involved in this trial, and the study will last three years. For those already infected, powerful drug combinations are able to decrease the amount of HIV virus in the blood to undetectable levels.