Epidemiological trends of AIDS in the United States.

The incidence of acquired immunodeficiency syndrome (AIDS) in the United States has increased rapidly since the first reports in 1981. Highest estimated rates are among single (never-married) men in Manhattan and San Francisco, men and women who have abused drugs intravenously, and persons with hemophilia. Serosurveys among populations at increased risk for AIDS have demonstrated a high prevalence of antibody to human T-cell leukemia virus III-lymphadenopathy-associated virus (HTLV-III/LAV), the virus which causes AIDS. The discovery of the virus and the widespread availability of serological tests greatly increase the ability to understand AIDS and to study the natural history of HTLV-III/LAV infection.