Seroepidemiologic study of hepatitis B virus infection at San Juan district in the Republic of Bolivia

The markers for hepatitis B virus including HBsAg and anti-HBs were determined in 484 sera obtained from 300 Japanese and 184 Bolivians living in the San Juan district in the Republic of Bolivia. In adults (older than 16 years old) HBsAg was detected in 7.1% of Japanese, but was not detected in Bolivians. As for anti-HBs, 45% of Japanese were positive, whereas 27% of Bolivian were positive. Among children (undre 16 years old), prevalence of HBsAg was 10% in Japanese and none in Bolivians, whereas anti-HBs were detected in 66% of Japanese and in 3.8% of Bolivians. Moreover, twenty six sera obtained from HBsAg positive subjects were tested for HBe antigen-antibody system by radioimmunoassay. In adults, 9.1% were positive for HBeAg, whereas 53% of children was HBeAg positive. Twenty five HBsAg-positive subjects were also tested for subtypes of HBsAg by hemagglutination inhibition method, revealing that 80% of HBsAg was subtype ‘adw’, and 20% of it was subtype ‘adr’.