title: Genotypic distribution of hepatitis C virus in Thailand and Southeast Asia.
abstract: The majority of hepatitis C virus (HCV) infection results in chronic infection, which can lead to liver cirrhosis and hepatocellular carcinoma. Global burden of hepatitis C virus (HCV) is estimated at 150 million individuals, or 3% of the world's population. The distribution of the seven major genotypes of HCV varies with geographical regions. Since Asia has a high incidence of HCV, we assessed the distribution of HCV genotypes in Thailand and Southeast Asia. From 588 HCV-positive samples obtained throughout Thailand, we characterized the HCV 5' untranslated region, Core, and NS5B regions by nested PCR. Nucleotide sequences obtained from both the Core and NS5B of these isolates were subjected to phylogenetic analysis, and genotypes were assigned using published reference genotypes. Results were compared to the epidemiological data of HCV genotypes identified within Southeast Asian. Among the HCV subtypes characterized in the Thai samples, subtype 3a was the most predominant (36.4%), followed by 1a (19.9%), 1b (12.6%), 3b (9.7%) and 2a (0.5%). While genotype 1 was prevalent throughout Thailand (27-36%), genotype 3 was more common in the south. Genotype 6 (20.9%) constituted subtype 6f (7.8%), 6n (7.7%), 6i (3.4%), 6j and 6m (0.7% each), 6c (0.3%), 6v and 6xa (0.2% each) and its prevalence was significantly lower in southern Thailand compared to the north and northeast (p = 0.027 and p = 0.030, respectively). Within Southeast Asia, high prevalence of genotype 6 occurred in northern countries such as Myanmar, Laos, and Vietnam, while genotype 3 was prevalent in Thailand and Malaysia. Island nations of Singapore, Indonesia and Philippines demonstrated prevalence of genotype 1. This study further provides regional HCV genotype information that may be useful in fostering sound public health policy and tracking future patterns of HCV spread.
authors.affiliation: Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Rujipat
authors.initials: R
authors.lastname: Wasitthankasem
authors.affiliation: Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Sompong
authors.initials: S
authors.lastname: Vongpunsawad
authors.affiliation: Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Nipaporn
authors.initials: N
authors.lastname: Siripon
authors.affiliation: Chiangrai Prachanukroh Hospital, Chiang Rai, Thailand.
authors.forename: Chutima
authors.initials: C
authors.lastname: Suya
authors.affiliation: Chiangrai Prachanukroh Hospital, Chiang Rai, Thailand.
authors.forename: Phrutsada
authors.initials: P
authors.lastname: Chulothok
authors.affiliation: Udon Thani Hospital, Udon Thani, Thailand.
authors.forename: Kasemporn
authors.initials: K
authors.lastname: Chaiear
authors.affiliation: Department of Pathology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
authors.forename: Pairaya
authors.initials: P
authors.lastname: Rujirojindakul
authors.affiliation: Regional Blood Center XI Nakhorn Si Thammarat, Thai Red Cross Society, Thung Song District, Nakhon Si Thammarat, Thailand.
authors.forename: Sawan
authors.initials: S
authors.lastname: Kanjana
authors.affiliation: Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Apiradee
authors.initials: A
authors.lastname: Theamboonlers
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Pisit
authors.initials: P
authors.lastname: Tangkijvanich
authors.affiliation: Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Yong
authors.initials: Y
authors.lastname: Poovorawan
mesh_terms: D000328:Adult; D001210:Asia, Southeastern / Q000453:epidemiology; D005260:Female; D005838:Genotype; D005843:Geography; D016174:Hepacivirus / Q000145:classification / Q000235:genetics*; D006526:Hepatitis C / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D058974:Phylogeography; D011159:Population Surveillance; D012367:RNA, Viral / Q000235:genetics; D013785:Thailand / Q000453:epidemiology
chemical_list: D012367:RNA, Viral