Identification of two novel hepatitis C virus subtype 2 from Tunisia (2v and 2w)

BACKGROUND: Hepatitis C virus (HCV) has a high genetic diversity. Eight genotypes and 90 subtypes are currently described. Genotypes are clinically significant for therapeutic management and their determination is necessary for epidemiological studies. METHODS: Tunisian patients plasma samples (n = 6) with unassigned HCV-2 subtype using partial sequencing in the NS5B and Core/E1 regions were analyzed by realizing whole-genome sequencing analysis. Phylogenetic analyses were performed to assign subtypes. RESULTS: Phylogenetic analysis of the full genome sequences of Tunisian strains shows two subtypes within HCV-2. These later were genetically distinct from all previously established HCV-2 subtypes with nucleotide divergence greater than 15% (20% -31%). These two subtypes are proposed as new subtypes 2v and 2w. CONCLUSIONS: The discovery of two new HCV-2 subtypes circulating in the Tunisian population confirms the great diversity of HCV-2 viruses and increases the total number of HCV-2 subtypes from 21 to 23.