HIV-1 infection in a Ugandan town on the trans-African highway: prevalence and risk factors.

All adult residents (aged 13 years or more) of 154 randomly selected households in 3 urban and one semi-rural ward of a town in South West Uganda on the trans-African highway were invited to participate in a socio-demographic, behavioural and medical survey. An unambiguous HIV-1 serostatus was obtained for 389 (80%) adults. The overall sero-prevalence rate was 40.4%; all age groups except males aged 13-19 years had infection rates in excess of 20%. Rates above 50% were found in females aged 20-34 years and males aged 35-44 years. For females seropositivity rates increased steeply with increasing numbers of lifetime sexual partners up to a maximum of 3; in contrast, for males rates continued to increase with increasing numbers of partners. The risk of infection amongst those with only one reported partner was 17%. A high proportion of males (14%) and females (18%) reported a history of genital ulcer disease within the previous 6 months; on examination genital lesions were observed in 12% of all participants. Interventions with a single focus are unlikely to have much impact in such a situation and a strategy is suggested which includes 3 components, namely improved STD control, a reduction in partner change and an increase in condom utilization.