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acquired immune deficiency syndrome (AIDS)
A disease caused by a retrovirus, called human immunodeficiency virus (HIV), that mainly attacks T-4 cells (which help the production of antibodies) and renders the body's immune system incapable of resisting infection. The first diagnosis was in New York in 1979. In 1983–84 scientists at the Pasteur Institute in France and the National Cancer Institute in the USA isolated HIV as the cause of the disease.
The virus can remain dormant in infected T-cells for up to 10 years. Early symptoms include severe weight loss and fatigue. The condition progresses to full-blown AIDS, characterized by secondary infections, neurological damage, and cancers (such as Kaposi's sarcomas and B-cell lymphomas).
AIDS is transmitted only by a direct exchange of body fluids. Methods of transmission include: sexual intercourse, sharing of contaminated needles by intravenous drug users, and infected mothers to their babies in the uterus. Before effective screening procedures were introduced many hemophiliacs were infected through transfusions of contaminated blood. Development of a vaccine has been hampered by the virus' constantly shifting genetic composition. Research has centered on treatment, and on delaying the onset of the full-blown syndrome. In 1986–87 the first chemical was produced which was partially successful in controlling symptoms, zidovudine or azidothymidine (AZT). More recently the emphasis has been on reducing the viral load – the amount of virus within the body – using a combination of AZT and newer drugs such as protease inhibitors.
Related category
• HEALTH AND DISEASE
Source: National Cancer Institute.
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