[Hepatitis C virus of genotype 5: a rare and unknown virus]

HCV genotype 5 (HCV 5) is rarely found outside of South Africa. However, a high prevalence has been reported in three European countries in limited geographical areas of Spain, Belgium and France. Two studies, supported by the ANRS, one epidemiological and the other using molecular virology, were made to investigate an epidemic in Auvergne, central France, where HCV 5 accounts for 14.2% of HCV infections. The origin of this outbreak was traced by phylogenetic analyses comparing local strains with those collected elsewhere in France. A Bayesian evolutionary method estimated the date of the most recent common ancestor of HCV 5 sequences in France to be 1939 [95% CI = 1921- 1956] and in central France 1954 [95% CI = 1942-1967]. Phylogenetic analysis confirmed the concomitant roles of transfusion, iatrogenic transmission (as the result of injections given by a country physician in the 1950s, 1960s and 1970s) and intra-familial transmission in the local spread of HCV 5a.