Epidemiology of Hepatitis C Virus Genotypes in Northeastern Thai Blood Samples

Background: Hepatitis C virus (HCV) infection is an important cause of liver cancer in Thailand. The highestprevalence of anti-HCV positive among Thai blood donors is found in the northeastern region. The presentanalysis of the genotype distribution among anti-HCV positive northeastern-Thai blood donors was conductedto provide a base for the epidemiological pattern of HCV infection in this region. Materials and
Methods: Atotal of 112 HCV seropositive healthy blood donors were randomly selected and tested for the presence of HCVRNAby RT-PCR. HCV-RNA positive samples were genotyped by direct sequencing at core region genomes andconfirmed by phylogenetic analysis.
Results: HCV viremia was found in 94.6% (106/112) of HCV seropositiveblood donors. There were 3 major genotypes distributed among this population. HCV genotype 3a was the mostprevalent (71.7%) followed by genotypes 1a (7.5%), 1b (7.5%), 6i (3.8%), 6f (2.8%) and 6n (1.9%).
Conclusions:HCV genotype 3a in asymptomatic infections in northeastern Thailand is significantly higher than other previousreports. Subgenotype 6 prevalence is less than in neighboring countries and distribution patterns differ. Thefindings are relevant as predictors for using interferon therapy in this population.