Viral hepatitis: new aspects of an old disease.

The new classification and nomenclature of viral hepatitis and serological markers of hepatitis viruses are presented. Modes of infection, clinical aspects and sequelae of viral hepatitis are outlined. The clinical significance of Australia antigen (HBsAg) is explained, stressing its prognostic value. The problem of asymptomatic HBsAg carriers is discussed and practical guidelines for the prevention of viral hepatitis outlined. The treatment of fulminant hepatitis is unsatisfactory and development of an artificial liver support system is badly needed. Future modes of immunization are listed.