title: Molecular epidemiology and genetic history of hepatitis C virus subtype 3a infection in Thailand.
abstract: OBJECTIVE
  Among all hepatitis C virus (HCV) infections, subtype 3a is the most common genotype in Thailand. This study investigates the molecular epidemiology and epidemic history of HCV subtype 3a in Thailand.
  
  
  METHODS
  Three hundred and fifty-six serum samples were collected from HCV-infected Thai patients. The virus was isolated, after which the core and NS5B regions were sequenced. Subsequently, the HCV genotype was classified by phylogenetic analysis based on the core and NS5B regions. Molecular evolution analysis of HCV subtype 3a was estimated using BEAST (Bayesian Evolutionary Analysis by Sampling Trees) v.1.5.4.
  
  
  RESULTS
  Based on our phylogenetic analyses, subtype 3a (38.5%) was the most prevalent, followed by 1a (21%), 1b (13.8%), genotype 6 (19.9%) [comprised of subtypes 6e (0.3%), 6f (11%), 6i (1.9%), 6j (1.9%) and 6n (4.8%)] and 3b (5.6%). Our phylogenetic tree indicates the existence of a specific group of HCV subtype 3a strains in the Thai population. Molecular evolutionary analysis dated the most recent common ancestor of the Thai HCV subtype 3a strains as existing approximately 200 ago, and a Bayesian skyline plot showed that this particular strain spread to Thailand during the mid-1970s and early 1980s. This period overlaps with the Vietnam War (1955-1975) and the widespread use of injection stimulants introduced by the US Army during this time.
  
  
  CONCLUSIONS
  The estimated history of HCV subtype 3a infection in Thailand may help to predict the future burden of HCV-related diseases and facilitate better public health control and surveillance.
authors.affiliation: Inter-Department of Biomedical Sciences, Faculty of Graduate School, Chulalongkorn University, Bangkok, Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Akkarathamrongsin
authors.forename: P
authors.initials: P
authors.lastname: Hacharoen
authors.forename: P
authors.initials: P
authors.lastname: Tangkijvanich
authors.forename: A
authors.initials: A
authors.lastname: Theamboonlers
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: M
authors.initials: M
authors.lastname: Mizokami
authors.forename: Y
authors.initials: Y
authors.lastname: Poovorawan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016000:Cluster Analysis; D019143:Evolution, Molecular; D005260:Female; D005838:Genotype; D016174:Hepacivirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006526:Hepatitis C / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013785:Thailand / Q000453:epidemiology; D014758:Viral Core Proteins / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics; D055815:Young Adult; D012324:RNA-Dependent RNA Polymerase
chemical_list: D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins; C069130:nucleocapsid protein, Hepatitis C virus; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase