Chronic carriers of hepatitis B surface antigen in an endemic area for shistosomiasis mansoni in Brazil

ABSTRACT

Data on the association of schistosomiasis and hepatitis B in field-based studies are scarce. Two areas have been selected for this study i) Queixadinha, endemic for shistosomiasis, with a population of 693 individuals, and ii) Capäo, a control non-endemic area, with 515 inhabitants. Sera of all individuals in both areas were tested for hepatitis B infection, yearly, from 1994 to 1997. In the first area hepatitis B was found in 32.1 per cent of children up to one year old and reached a peak of 68.7 per cent in the age range of 15 to 19 years. In the control area the prevalence of hepatitis B was under 5 per cent up to 19 years of age and the highest prevalence was observed in adults over 45. HBsAg was detected in 9.4 per cent of the individuals living in the endemic area for shistosomiasis and in 1.4 per cent of the controls (OR=4.98; 95 per centCI=3.7-6.7). The index of chronicity of HBsAg was not statistically different in the studied areas (8.1 per cent x 7.3 per cent; OR=1.09; 95 per cent CI=0.42-3.03) nor was it different for people with and without schistosomiasis in Queixadinha (8.7 per cent x 7.0 per cent). We conclude that the Schistosoma mansoni infection has not altered the course of hepatitis B in the studied area.