Seroprevalence of HIV, hepatitis B, and syphilis in an urban population and isolated villages in Gabon

interval of 95%. The observed diVerences were considered as significant for an alpha error of 5%. The seroprevalence rates were adjusted by sex. Results The seroprevalence rates for HIV are not significantly diVerent in the two population (table 1), and remain lower than in the capital, Libreville (3.7% among the blood donors in 1995). In Franceville, the seroprevalence rate of HIV-1 has doubled since the last similar survey in 1988. 2 During the same time, this rate has multiplied by only 1.3 in Libreville. The HIV seroprevalence in the two populations and, more generally in Gabon, stays relatively low compared with the seroprevalence commonly noted in Central Africa. No HIV-2 was found during these surveys, confirming its very low seroprevalence in Gabon. 3 The population at risk for hepatitis B is diVerent in the two sites. In Franceville, the risk of being Ag HBs positive is greater for west Africans than for central Africans (7/20 v 53/419, RR=2.77, 95% CL=1.45‐5.29), but this risk exists only for women cohabiting. So it is mainly the social status of these immigrant women that exposes them to the risk of contamination—cloistered at home, with little access to prevention and treatment, they are the inevitable victims of the extraconjugal contaminations of their husband. In the villages, trading is the risk factor but only among men (13/31 v 28/118, RR=1.83, 95% CL=1.08‐3.08). It could be proposed that travelling to the city to restock would permit a man to have more sexual partners than a woman. The seroprevalence rate of syphilis in Franceville is low for a central African city. 45