THE EPIDEMIOLOGY OF HIV-INFECTION IN A RURAL AREA OF GUINEA-BISSAU

Objectives: To determine the prevalence of HIV infection and its relat ionship to age, sex and other factors. Design and setting: Cross-secti onal survey of a rural community in Guinea-Bissau. Methods: Questionna ire-administration and screening of sera from subjects aged greater-th an-or-equal-to 15 years. Results: Of the 2770 subjects tested, 220 (7. 9%) were HIV-2-seropositive, four (0.1%) were HIV-1-seropositive and 1 0 (0.4%) were dually reactive. Overall prevalence of HIV-2 was 9.3% in women, peaking at 17.2% in the 35-44 age group, and 6.6% in men, peak ing at 19.1% in the 45-54 age group. The mean age of the four subjects with HIV-1 infection was 24 years, which was significantly lower than those with HIV-2 infection. HIV-2 infection was more prevalent among women who were widowed or divorced, women whose husbands were living a way from the study area, and women who had lived in the capital, Bissa u. The majority of subjects with an infected spouse remained uninfecte d and none of the women aged < 25 years whose husbands were infected w ere seropositive. The prevalence varied significantly between settleme nts within the study area. Conclusions: The pattern of HIV-2 infection in this rural community has similarities to that found in urban Bissa u, and prevalence in both areas peaks in older subjects than in HIV-1 foci. The findings support previous suggestions that HIV-2 is not a re cent introduction to Guinea-Bissau, and that it is less pathogenic and less readily transmitted than HIV-1.