Geographic variation of genotype 6 hepatitis C virus infection in an endemic area of southern Taiwan

Abstract

Taiwan is a hepatitis C virus (HCV) endemic country with geographic variation of prevalence and main genotypes(GTs) are 1b and 2a. We recently reported high GT6 prevalence in Tainan of southern Taiwan. To clarify this special genotype as a local endemic disease and its geographic variation, the prevalence rates of HCV GTs of 37 districts of Tainan were analyzed. A total of 3040 patients with HCV viremia were enrolled. The prevalence rates of HCV GT 1a, 1b, 2, 3, 4, 6 and mixed types were 3.9%, 31.6%, 45.9%, 0.6%, 0.2%, 17.1% and 0.5% respectively. GT6 prevalence showed marked variation from 0 to 39.2%. Four districts with GT6 prevalence >30% are located between Jishui and Zengwen rivers. Preliminary subtyping data were 6g/a/w. This geographic variation with spatial restriction by two rivers with 6g/w is suggestive of local endemic infection of preexisting GT 6 HCV for centuries.