Genotype Distribution and Molecular Epidemiology of Hepatitis C Virus in Guangzhou, China: Predominance of Genotype 1b and Increasing Incidence of Genotype 6a

Background/Aims: Distribution of Hepatitis C virus (HCV) genotypes vary geographically and may associate with the mode of transmission. Little is known about the molecular epidemiology of HCV infection in Guangzhou, China. Methods: A cross-sectional survey included 561 subjects with chronic HCV infection registered at Nanfang Hospital, Southern Medical University, was performed. All residents were invited for a questionnaire interview to collect information about their personal status and commercial blood donation history. Results: A total of 463 chronic hepatitis C (CHC) patients were finally enrolled. Among the 463 samples, 426 were characterized by partial core-E1 sequences and classified into 7 subtypes: 1b (n=263, 61.7%), 6a (n=86, 20.2%), 2a (n=26, 6.1%), 3b (n=26, 6.1%), 3a (n=22, 5.2%), 6u (n=2, 0.5%), and 4a (n=1, 0.2%). Analysis of genotype-associated risk factors revealed that blood donation and transfusion were strongly associated with subtypes 1b and 2a, while genotype 3b and 6a were more frequent in intravenous drug users. Conclusions: Phylogeographic analyses demonstrated that the distribution of HCV genotypes in Guangzhou is complex. Interestingly, 6a has become a local endemic in Guangzhou and may be the second source region to disseminate 6a to other provinces.