title: Emergence and predominance of norovirus GII.17 in Huzhou, China, 2014-2015.
abstract: BACKGROUND
  Norovirus (NoV) has been recognized as the leading cause of both outbreaks and sporadic cases of acute gastroenteritis in children and adults worldwide. Stool samples collected from outpatients with clinical symptoms of acute gastroenteritis in all age groups at the First People's Hospital in Huzhou, Huzhou, China between March 2014 and February 2015 were analyzed to gain insight into the epidemiology and genetic variation in NoV strains circulating in China.
  
  
  METHODS
  Real-time RT-PCR (qPCR) was performed for Norovirus detection. RT-PCR were used for genomic amplification and sequencing. Genogroup and genotype were assigned using the NoV Noronet typing tool and the strains were named according to the time of isolation. The phylogenetic analysis was conducted using MEGA 5.
  
  
  RESULTS
  Of the 809 specimens, 193 (23.9 %) were positive for NoV, with GII.4 and GII.17 the most commonly identified strains. Phylogenetic analysis confirmed the presence of five recombinant strains in Huzhou. Recombinants GII.P13/GII.17 and GII.P12/GII.4 were newly detected in China. The GII.P13/GII.17 recombinant was first identified in October 2014 and steadily replaced GII.Pe/GII.4 (GII.4 Sydney 2012) as the predominant circulating NoV genotype.
  
  
  CONCLUSIONS
  This is the first report of the detection of GII.17 in the Huzhou area and of a NoV genotype being detected in greater numbers than GII.4. Furthermore, our results indicated that following the emergence of GII.17 in October 2014, it steadily replaced the previous circulating GII.4 Sydney2012 strain, which was the dominant circulating genotype for the past 2 years. As norovirus are the important cause of nonbacterial gastroenteritis, continuous and comprehensive study of the norovirus strains involved in large and cost-effective acute gastroenteritis would help understanding the molecular epidemiology of norovirus infections and development of improved prevention and control measures.
authors.affiliation: Huzhou Center for Disease Control and Prevention, 999 Changxing Road, Huzhou, Zhejiang, 313000, China. 51145219@qq.com.
authors.forename: Jiankang
authors.initials: J
authors.lastname: Han
authors.affiliation: Huzhou Center for Disease Control and Prevention, 999 Changxing Road, Huzhou, Zhejiang, 313000, China. jileichn@163.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Ji
authors.affiliation: Huzhou Center for Disease Control and Prevention, 999 Changxing Road, Huzhou, Zhejiang, 313000, China. 513360082@qq.com.
authors.forename: Yuehua
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Huzhou Center for Disease Control and Prevention, 999 Changxing Road, Huzhou, Zhejiang, 313000, China. 479662477@qq.com.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Wu
authors.affiliation: Huzhou Center for Disease Control and Prevention, 999 Changxing Road, Huzhou, Zhejiang, 313000, China. 574831399@qq.com.
authors.forename: Deshun
authors.initials: D
authors.lastname: Xu
authors.affiliation: Huzhou Center for Disease Control and Prevention, 999 Changxing Road, Huzhou, Zhejiang, 313000, China. lipingchen1106@hotmail.com.
authors.forename: Liping
authors.initials: L
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D005243:Feces / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology / Q000821:virology; D005838:Genotype; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D029322:Norovirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D055815:Young Adult
chemical_list: D012367:RNA, Viral