Transmissible disease of the immune system caused by HIV. AIDS is the last stage of HIV infection, during which time the individual develops frequently fatal infections and cancers, including Pneumocystis carinii pneumonia, cytomegalovirus (CMV), lymphoma, and Kaposi sarcoma. The first AIDS cases were identified in 1981, HIV was isolated in 1983, and blood tests were developed by 1985. According to the UN's 2004 report on AIDS, some 38 million people are living with HIV, approximately 5 million people become infected annually, and about 3 million people die each year from AIDS. Some 20 million people have died of the disease since 1981. Sub-Saharan Africa accounts for some 70 percent of all HIV infections. Rates of infection are lower in other parts of the world, but the epidemic is spreading rapidly in eastern Europe, India, South and Southeast Asia, Latin America, and the Caribbean.
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The term AIDS (for acquired immune deficiency syndrome) was proposed in 1982 by Sasu Siegelbaum, among other researchers, concerned with the accuracy of the disease's name. In this new name, scientists were supported by political figures who realized that the term "gay-related" did not accurately describe the demographic that the disease affected. On April 23, 1984, the U.S. Department of Health and Human Services Secretary announced at a press conference that an American scientist, Dr. Robert Gallo, had discovered the probable cause of AIDS: the retrovirus subsequently named human immunodeficiency virus or HIV in 1986.