MOLECULAR EPIDEMIOLOGY OF HEPATITIS-C VIRUS-INFECTION AMONG INTRAVENOUS-DRUG-USERS

Background/Aims: The clinico-pathological features of hepatitis C viru s infection in intravenous drug users are different from those found i n other hepatitis C virus-infected patients, Our aim was to test wheth er specific viral variants circulate within this particular patient po pulation. Methods: We studied the distribution of hepatitis C virus ge notypes in 90 drug addicts and 484 controls, according to the method d escribed by Okamoto. Results: Hepatitis C virus type la and 3a infecti ons were more frequent among intravenous drug users than in 125 age-ma tched controls (48.8% and 21.1% vs 17.6% and 11.2%), accounting for th e majority of infections in intravenous drug users, Analysis of hepati tis C virus genotypes according to age showed that,in the general popu lation, hepatitis C virus types la and 3a were more prevalent among pa tients younger than 40 years of age than in older individuals (17.6% a nd 11.2% vs. 1.4% and 0.6%). Conclusions: These findings suggest that hepatitis C virus types la and 3a were recently introduced in Italy, p resumably via needle-sharing among intravenous drug users, and from th is reservoir they are extending to the general population, particularl y among younger subjects.