The epidemiology and prevention of the acquired immunodeficiency syndrome.

The incidence of the acquired immunodeficiency syndrome (AIDS) has continued to increase worldwide. From June 1981 to September 1985, 12 932 cases have been diagnosed and reported in the United States; this number is expected to double during the next year. The incubation period is long and few persons infected with human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) have AIDS diagnosed within 2 to 5 years of infection. The widespread use of HTLV-III/LAV serologic tests to screen donated blood and plasma, the continued deferral of donors from groups with an increased incidence of AIDS, and the use of heat-treated clotting factor concentrates should help prevent HTLV-III/LAV transmission through blood and blood products. Preventing transmission among sexual partners, among intravenous drug users, and from infected mothers to newborns will continue to be difficult without a vaccine, specific antiviral therapy, or both. Risk reduction strategies should involve community groups to provide accurate information and influence behaviors that lead to transmission of the virus.