Changing molecular epidemiology of hepatitis C virus infection in northeast Italy

To assess HCV genotype distribution and its determinants, 318 consecutive HCV RNA positive patients were examined. Subtype 1b infection was the most prevalent (35.5%), followed by subtype 1 a (22%),3a (21.4%) and 2 genotype (21.3%). Subtypes la, 1b and 3a had a comparable prevalence (30-35%) in the 0-15-, 16-30- and 31-45-year age groups. In subjects older than 45 years, genotype 2 prevalence increased, whereas subtype la and 3a infections decreased markedly. In this age group types 1b and 2 accounted for a prevalence of more than 90% in a comparable proportion. Genotype prevalence rates according to different risk factors were different statistically (P < 0.001): subtype la and 3a infections were predominant in injection drug users (42.9% and 37.7%, respectively), whereas community acquired infections and infections in patients with a history of transfusion were caused mainly by subtype 1b (38.5% and 66.6%, respectively). Logistic regression showed that age and injection drug use are independent determinants of genotype distribution. (C) 2002 Wiley-Liss, Inc.