The importance of the quasispecies nature of hepatitis C virus (HCV) for the evolution of HCV populations in patients: study on a single source outbreak of HCV infection.

The quasispecies populations of hepatitis C virus (HCV) in the infectious source (IS) and in patients of a single source outbreak were characterized. A predominant variant AD78-1 and some minor variants of HCV 5' NCR were identified in IS. Different complex HCV populations emerged rapidly in patients though HCV populations in chronic infection were rather simple and stable. AD78-1 remained predominant in 17/24 chronically infected patients while new predominant variants with distinct nucleotide substitutions persisted in 7 other patients. Thus, only distinct variants are involved in viral persistence and the genetic heterogeneity of HCV does not successively increase with time.