Epidemiology, clinical course and treatment of chronic viral hepatitis.

Chronic hepatitis may take the form of a hepatitis B infection, a delta virus infection, or a non-A, non-B hepatitis including hepatitis C. All the viruses involved are transmitted predominantly by parenteral or sexual routes. New insights into the structure of the hepatitis B virus (HBV) and the immune response mechanisms of the organism permit a clear definition of the replicative state of the virus, and allow predictions to be made about the outcome of the disease. Development of cirrhosis and hepatocellular carcinoma are the major complications associated with impaired life expectancy. Recently, the hepatitis C virus (HCV) was identified as the agent responsible for most cases of chronic non-A, non-B hepatitis. The development of an assay for the detection of HCV-antibodies facilitated the diagnosis of this type of hepatitis. Moreover, the use of screening tests for hepatitis B and hepatitis C in blood donors will decrease the risk of acquiring hepatitis via contaminated blood products. Treatment of chronic hepatitis B and C with alpha-interferon has shown promising results. However, the dosage schedule, the period of treatment, and the selection of patients needs to be evaluated in further studies.