title: [Genetic variation of the hemagglutinin and neuraminidase of influenza B viruses isolated in Zhejiang province during 1999 - 2010].
abstract: OBJECTIVE
  To characterize the genetic diversity of hemagglutinin (HA) and neuraminidase (NA) of influenza B viruses isolated in Zhejiang province during 1999 - 2010.
  
  
  METHODS
  Respiratory specimens were collected from patients with flu-like syndrome during the influenza outbreaks or from the hospitals which carrying out influenza surveillance project in Zhejiang province. Samples were detected by real-time RT-PCR and isolated for influenza virus. HA(1) and NA genes of influenza B virus isolates were amplified and sequenced. Phylogenetic comparison and genetic diversity analysis were performed using the bioinformation software.
  
  
  RESULTS
  A total of 34 influenza B viruses were evolved in this study including Victoria-like and Yamagata-like strains according to the results of the HI test. The mutation rate of Victoria-like HA(1) gene was 4.5% and Yamagata-like HA(1) gene was 3.4%, respectively. The Victoria-like influenza B isolates had appeared to be all reassortants having a Victoria lineage HA and Yamagata lineage NA since 2004. The predominant type of influenza virus isolates in 2010 was also influenza B virus after the H1N1 flu pandemic in Zhejiang province. The isolated strains were antigenically and genetically similar to B/Brisbane/60/2008-the vaccine strain proposed for 2009 - 2010. Many differences of HA(1) and NA amino acids existed in the current isolates when compared to previous influenza B strains.
  
  
  CONCLUSIONS
  Significant diversity was generated among influenza B virus isolated from 1999 to 2010 in Zhejiang province. Genetic re-assortment and antigenic drift seemed the main evolutionary mechanism on influenza B virus.
authors.affiliation: Virus Institute, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Mao
authors.forename: Min
authors.initials: M
authors.lastname: Zhou
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Yin
authors.initials: Y
authors.lastname: Chen
authors.forename: Chang-Ping
authors.initials: CP
authors.lastname: Xu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Ju-Ying
authors.initials: JY
authors.lastname: Yan
authors.forename: Yi-Yu
authors.initials: YY
authors.lastname: Lu
mesh_terms: D002681:China / Q000453:epidemiology; D014644:Genetic Variation; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics*; D006801:Humans; D009981:Influenza B virus / Q000235:genetics* / Q000302:isolation & purification; D009439:Neuraminidase / Q000235:genetics*; D010802:Phylogeny; D016865:Reassortant Viruses / Q000235:genetics / Q000302:isolation & purification
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; C493831:hemagglutinin HA1, influenza B virus; D009439:Neuraminidase