Changes in the prevalence of hepatitis C virus (HCV) genotype 4 in Calabria, Southern Italy.

The aim of this study was to assess changes in the prevalence of hepatitis C virus (HCV) genotypes, focusing on genotype 4, by surveying population of chronic hepatitis C patients within an area of Southern Italy. HCV-RNA was detected in serum using two commercial hepatitis C RNA PCR assays (Amplicor Roche Diagnostic System, and AmpliSensor HCV, Nuclear Laser Medicine). PCR products were analyzed for genotyping using a reverse hybridization of the amplified product by a line probe assay (INNO LIPA, Innogenetics). In our Institution we have previously observed, in a period of 18 months (January 1997-May 1998) an initial increase of the genotype 4 which appeared in 3.3% of HCV patients versus a percentage of 1.3%, during 1996. Later data obtained from 702 HCV-RNA positive patients, collected from June 1998 until December 1999 indicated a 3.7% of genotype 4. This percentage increased until to 4.7% in the most recent period studied (January 2000-February 2001). Drug addiction, blood transfusion and sporadically acquired infections represented the most frequent risk factors. In the Calabria region, genotype 1b, the most prevalent isolate (53.3%) and genotype 2a/2c (26.2%) were associated with older age, confirming our previous study. Genotype 4 was the fifth most prevalent genotype observed, just after 3a and 1a subtypes. Spread of genotype 4 in Calabria region is mostly associated to older age when compared to genotype 3a and 1a, but is statistically associated with a younger group of patients when compared with genotype 1b. In conclusion we demonstrated a fourfold increased prevalence of HCV genotype 4 during the last 5 years.