EPIDEMIOLOGIC ASPECTS OF HEPATITIS-B AND HEPATITIS-D VIRUS-INFECTION IN THE NORTHERN REGION OF AMAZONAS, BRAZIL

The State of Amazonas in the Brazilian Amazon region is an area of hig h prevalence of hepatitis B and D virus (HBV and HDV) infection. The a im of this study was to identify epidemiological patterns and risk fac tors of HBV and HDV infections in Barcelos, in the basin of the Negro river. A random sample (798 in all) of the total population in the urb an area and in 2 rural villages was surveyed. A standardized questionn aire was used and blood samples were tested by enzyme-linked immunosor bent assay: 1.63% had hepatitis B surface antigen, 12.9% had anti-hepa titis B surface antibody and 21.4% had anti-hepatitis B core antigen. The overall prevalence of HBV infection was 24.6%. Anti-hepatitis D wa s present in 5 subjects, all of them non-natives, and hepatitis B e an tigen in 2. A positive association between history of dental treatment with an unqualified dental surgeon was found (P < 0.05). These result s suggest a low prevalence of HVB and HDV infection, in contrast with other parts of the Amazon area.