Hepatitis C virus genotype 6:Virology,epidemiology,genetic variation and clinical implication

Hepatitis C virus(HCV)is a serious public health problem affecting 170 million carriers worldwide.It is a leading cause of chronic hepatitis,cirrhosis,and liver cancer and is the primary cause for liver transplantation worldwide.HCV genotype 6(HCV-6)is restricted to South China,South-East Asia,and it is also occasionally found in migrant patients from endemic countries.HCV-6 has considerable genetic diversity with23 subtypes(a to w).Although direct sequencing followed by phylogenetic analysis is the gold standard for HCV-6 genotyping and subtyping,there are also now rapid genotyping tests available such as the reverse hybridization line probe assay(INNO-LiPAⅡ;Innogenetics,Zwijnaarde,Belgium).HCV-6 patients present with similar clinical manifestations as patients infected with other genotypes.Based on current evidence,the optimal treatment duration of HCV-6 with pegylated interferon/ribavirin should be 48 wk,although a shortened treatment duration of 24 wk could be sufficient in patients with low pretreatment viral load who achieve rapid virological response.In addition,the development of direct-acting antiviral agents is ongoing,and they give high response rate when combined with standard therapy.Herein,we review the epidemiology,classification,diagnosis and treatment as it pertain to HCV-6.