[Seroepidemiological study on hepatitis C virus infection in an endemic area of hepatitis C virus].

To clarify the prevalence of hepatitis C virus infection in a rural area with high incidence of chronic liver disease in Japan, sera from 412 inhabitants, aged 20-89 years, collected in 1989-1990 and sera from 483 inhabitants in the same area, collected in 1982 were tested for anti-HCV (antibody to C100-3) with the first-generation enzyme-linked-immunosorbent-assay (ELISA). In addition, sera from 118 inhabitants, aged 20-49 years, collected in 1989-1990 were tested for HCV-RNA with the polymerase chain reaction technique, with use of primers from the 5'-untranslated region of the HCV genome. Anti-HCV was positive in 175 out of 412 sera collected in 1989-1990 (42.5%): prevalence was higher in male (54.0%) than in female (34.9%). The prevalence rates in the 20-29, 30-39, 40-49, 50-59, 60-69, and 70-89 year-old group were 0%, 14.3%, 51.9%, 41.7%, 49.1%, and 53.1%, respectively. On the other hand, in sera collected in 1982, the overall prevalence of anti-HCV was 42.5% (175 of 412). The prevalence rates in the 20-29, 30-39, 40-49, 50-59, 60-69, and 70-89 year-old group were 12.5%, 43.3%, 51.5%, 50.3%, 60.7%, and 68.9%, respectively. The prevalence rate of young adults less than 40 years old in 1982 were higher than that in 1989-1990. In short, the prevalence of hepatitis C virus infection in this area had altered a great deal. HCV-RAN was detected in 42 of 118 (35.6%).(ABSTRACT TRUNCATED AT 250 WORDS)