[Diagnosis and epidemiology of hepatitis C]

After years of unsuccessful attempts to isolate the causative agent of hepatitis non-A-non-B this has recently been accomplished. The nucleic acid of a virus, now called hepatitis C, was cloned which formed the basis of a diagnostic ELISA. In this test antibodies against a non-structural protein of the virus can be detected. These antibodies are not actually protective but rather indicate virus activity. The first generation test is hampered by some unspecificity but mostly by the fact that seroconversions are detected very late, sometimes up to 6 months after infection. However by including some more antigens in the ELISA of the second generation this problem will hopefully be overcome. Hepatitis C virus (HCV) antibodies could be found in up to 90% of patients with posttransfusion hepatitis. But also about 75% of patients with sporadic (cryptogenetic) hepatitis, were positive for HCV. Beside multiple blood transfusions (0.7% of blood donors in Austria are infected) other risk factors for HCV are needle sharing by i.v. drug users and treatment for hemophilia, because of HCV is not inactivated during the preparation of antihemophilic plasma. A virus inactivating procedure is therefore carried out in modern preparations. A high percentage of hemodialysis patients are also infected. However, important differences (0 to 30%) were found between different dialysis units. Other investigations revealed that the HCV risk for medical personnel is not extremely high, perhaps only twice that of the normal population. Sexual transmission of the virus seems to be possible but not of practical importance. Although the majority of hepatitis cases which earlier were classified as non-A-non-B, can now be diagnosed as hepatitis C, the possible existence of one more hepatitis virus cannot be excluded.