EPIDEMIOLOGY OF HEPATITIS-C VIRUS-INFECTI ON IN IN FRANCE

In France, the population of adult carriers of anti-HCV antibodies has been estimated about 600.000, but only 10 to 15 % are aware of the di agnosis. Two major sources of infection have been identified : transfu sion and intravenous drug use, accounting for 60 % of HCV infections. In contrast, sexual or household transmission, mother-to-infant transm ission or occupational exposure account for a small part of the HCV ep idemic. In about 15 % of cases, a nosocomial exposure is questionned, probably related to an insuficient decontamination of medical devices. Finally, no source of infection can be recognized in about 20 % of in fected patients. Among them, many have spent a long stay in high HCV p revalence areas, suggesting local percutaneous exposures. The diagnosi s of chronic hepatitis C is often made late in the course of the disas e, an average of 10 years after exposure. At this time, a cirrhosis is present in about 20 % of the patients. The frequency of cirrhosis dep ends on the duration of the HCV infection, and probabably also on the source of transmission, independently of the duration of the disease. Thus, it has been observed that cirrhosis was more frequent in transfu sion recipients than in intravenous drug users. Such a difference coul d be related to different HCV genotypes in the different groups at ris k. The genotype Ib has been found predominant in transfusion recipient s whereas genotype 3a was more frequent in drug users. Recently, a sli ght modification in the relative frequency of the different genotypes, mainly spreading and increased frequency of genotype 3a could lead to a modified epidemiology of HCV infection. The consequences of such mo difications need to be evaluated.