Prevalence of HIV-1 infection in rural, semi-urban and urban villages in southwest Tanzania: estimates from a blood-donor study.

Objectives: To measure the prevalence of HIV-1 infection in different subgroups of blood donors and to identify groups at high risk of acquiring HIV-1.

Methods: Between March 1988 and April 1991 all blood donors at Ilembula Lutheran Hospital, Tanzania were asked about their age, marital status, home village and occupation, and tested for the presence of HIV antibodies using a first generation, whole virus lysate enzyme-linked immunosorbent assay (ELISA). Some negative (n = 265) and nearly all positive samples (439 out of 485) were subjected to confirmatory testing including recombinant and peptide-based ELISA and Western blot assays.