SITUATION IN FRANCE: The prevalence of hepatitis C virus (HCV) infection in the French population is estimated at 1%, a level similar to that in other western countries. USUAL CONTAMINATION ROUTES: Epidemiological studies, together with gene typing, have made it possible to distinguish transmission modes. A history of intravenous drug abuse or transfusion is found in 60 to 80% of all subjects infected by the HCV. Other documented modes of contamination include hemodialysis, organ transplantation, accidental occupational-related puncture and mother-infant transmission. OTHER ROUTES: Sexual or intra-familial nonsexual transmission is uncommon and related to the length of exposure and the stage of HCV infection in the "source" subjects. Cases of HCV transmission have been reported during medical procedures. Currently the mode of of transmission is unknown in 20 to 40% of the cases.