Acute sporadic non-A, non-B viral hepatitis of adults in India- epidemiological and immunological studies

On the basis of tests for specific IgM class antibodies in the serum, infections by hepatitis A virus, hepatitis B virus and hepatitis non-A, non-B virus accounted for 7%, 37.8% and 54.2% respectively of 286 cases of acute sporadic viral hepatitis in adults from three different regions of India. Epstein-Barr virus and cytomegalo virus were insignificant (0.5-1%) aetiological agents. Approximately one-quarter of all non-A, non-B (NANB) cases were additionally HBsAg carriers; there were significant differences in regional frequencies. NANB hepatitis commonly affected individuals in the mid-fourth decade and occurred throughout the year with small peaks in different seasons. No antigen-antibody reaction could be demonstrated in various immunological tests including radioimmunobinding using acute and convalescent phase sera. Neither were virus-like particles visualized in acute phase sera on electron and immuno-electron microscopy. However, rhesus monkeys inoculated with acute phase serum from a case of NANB hepatitis developed distinct hepatocellular changes at 43-55 days after inoculation, which had some features of similarity with experimental NANB hepatitis of other simian species. Sporadic NANB hepatitis is a major health problem throughout India and intensive study is needed on its epidemiology and aetiology