Evidence of increasing diversification of hepatitis C viruses.

Hepatitis C virus (HCV) has high genomic variability and, since its discovery, at least six different types and an increasing number of sub-types have been reported. The HCV genotype may influence virus replication, the natural course of disease and the response to therapy. HCV has been described as a dynamic population of heterogeneous, closely related variants, designated quasispecies. In order to study the degree of genetic variability of strains isolated in Montevideo, Uruguay, sequence data obtained from the 5' non-coding region of type 1-infected patients were compared with published sequences from 53 different strains of all types isolated all over the world. The phylogenetic analysis revealed that type 1 strains isolated in Montevideo represent a different genetic lineage from major sub-types 1a and 1b strains and indicates an increasing diversification of HCV viruses.