title: Hepatitis C virus genotype and subtype distribution in Chinese chronic hepatitis C patients: nationwide spread of HCV genotypes 3 and 6.
abstract: BACKGROUND
  Hepatitis C virus (HCV) genotype and subtype are related to disease progression and response to antiviral therapy. Current HCV genotype and subtype distribution data, especially for genotypes 3 and 6, are limited in China. Our purpose was to investigate the current HCV genotype and subtype distributions in chronic hepatitis C patients in China.
  
  
  METHODS
  Chronic hepatitis C patients (n = 1012) were enrolled, and demographic information and possible transmission risk factors were collected. Serum samples were subjected to reverse-transcription polymerase chain reaction, followed by direct DNA sequencing and phylogenetic analysis of the NS5B and core/E1 regions to determine HCV genotypes/subtypes. The geographical distributions of HCV genotypes/subtypes were analyzed. Demographic information and transmission risk factors were compared between different HCV genotypes/subtypes.
  
  
  RESULTS
  Four genotypes and seven subtypes of HCV were detected in 970 patients. Subtypes 1b, 2a, 3a, 6a, 3b, 6n, and 1a were detected at frequencies of 71.96%, 19.90%, 3.20%, 2.16%, 1.96%, 0.41%, and 0.41%, respectively. Genotypes 3 and 6 showed an increasingly wide geographic distribution over time. Patients with subtypes 1b and 2a were older than those with 3a, 3b, 6a, and 6n subtypes (p < 0.05 in all subtypes). More genotype 1 and 2 patients underwent blood transfusion than those with genotype 3 (all p < 0.05). More genotype 3 and 6 patients had a history of intravenous drug use than those with genotypes 1 and 2 (all p < 0.05).
  
  
  CONCLUSIONS
  Though subtypes 1b and 2a are still the most prevalent HCV subtypes in China, genotype 3 and 6 HCV infections have already spread nationwide from southern and western China.
authors.affiliation: Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, 8 East Jingshun Street, Chaoyang District, Beijing, 100015, China. orangewei27@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Ju
authors.affiliation: Center of Hepatology, Beijing Ditan Hospital, Capital Medical University, 8 East Jingshun Street, Chaoyang District, Beijing, 100015, China. sduyangsong@163.com.
authors.forename: Song
authors.initials: S
authors.lastname: Yang
authors.affiliation: Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, 8 East Jingshun Street, Chaoyang District, Beijing, 100015, China. fsh626@sina.com.
authors.forename: Shenghu
authors.initials: S
authors.lastname: Feng
authors.affiliation: Center of Hepatology, Beijing Ditan Hospital, Capital Medical University, 8 East Jingshun Street, Chaoyang District, Beijing, 100015, China. wangqidl04@126.com.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, 8 East Jingshun Street, Chaoyang District, Beijing, 100015, China. liusa1031@sina.com.
authors.forename: Shunai
authors.initials: S
authors.lastname: Liu
authors.affiliation: Center of Hepatology, Beijing Ditan Hospital, Capital Medical University, 8 East Jingshun Street, Chaoyang District, Beijing, 100015, China. huichunxing@126.com.
authors.forename: Huichun
authors.initials: H
authors.lastname: Xing
authors.affiliation: Center of Hepatology, Beijing Ditan Hospital, Capital Medical University, 8 East Jingshun Street, Chaoyang District, Beijing, 100015, China. xiewen6218@163.com.
authors.forename: Wen
authors.initials: W
authors.lastname: Xie
authors.affiliation: Department of Infectious Diseases, The Fourth Hospital of Harbin Medical University, 37 Yiyuan Street, Nangang District, Harbin, 150081, China. zlyhmu@163.com.
authors.forename: Liying
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, 8 East Jingshun Street, Chaoyang District, Beijing, 100015, China. chengj0817@sina.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Cheng
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D005838:Genotype; D016174:Hepacivirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D019698:Hepatitis C, Chronic / Q000453:epidemiology / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D012367:RNA, Viral / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D044967:Serum / Q000821:virology; D014758:Viral Core Proteins / Q000235:genetics; D014759:Viral Envelope Proteins / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics; D055815:Young Adult; D012324:RNA-Dependent RNA Polymerase
chemical_list: D012367:RNA, Viral; D014758:Viral Core Proteins; D014759:Viral Envelope Proteins; D017361:Viral Nonstructural Proteins; C087035:E1 protein, Hepatitis C virus; C069130:nucleocapsid protein, Hepatitis C virus; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase