Nationwide community-based serological survey of HIV-1 and other human retrovirus infections in a central African country. Rwandan HIV Seroprevalence Study Group.

In December, 1986, a nationwide serological survey of human immunodeficiency virus type 1 (HIV-1) infection in the general population of Rwanda was done in two parts--one in the rural and the other in the urban population. The sampling method was a modification of the cluster sampling technique developed for monitoring immunisation coverage. Antibodies to HIV-1 (and to HIV-2 and human T-cell leukaemia/lymphoma virus type I [HTLV-I]) were detected by immunoenzymatic assays and confirmed by western blot. The number of clusters surveyed was 30 in each setting, urban and rural. HIV-1 seroprevalence was 17.8% (95% confidence interval 14.3-21.2%) in the urban sample (n = 1870) and 1.3% (0.5-2.2%) in the rural sample (n = 742). In the urban sample, females were more frequently HIV-1 seropositive than males (21.0% vs 14.6%). Age-specific peaks of HIV-1 seroprevalence were identified at 0 to 5 years of age (10.1%) and at 26-40 years (30.0%). No differences in seroprevalence were observed in terms of age and sex in the rural sample. None of the sera were seropositive for HIV-2 and HTLV-I seroprevalence was 0.2% in the urban sample and 0.3% in the rural. Nationwide serological surveys could be effective in evaluating the spread of HIV infection and the efficacy of public health interventions against AIDS in developing countries.