title: Genetic mutations in influenza H3N2 viruses from a 2012 epidemic in Southern China.
abstract: BACKGROUND
  An influenza H3N2 epidemic occurred throughout Southern China in 2012.
  
  
  METHODS
  We analyzed the hemagglutinin (HA) and neuraminidase (NA) genes of influenza H3N2 strains isolated between 2011-2012 from Guangdong. Mutation sites, evolutionary selection, antigenic sites, and N-glycosylation within these strains were analyzed.
  
  
  RESULTS
  The 2011-2012 Guangdong strains contained the HA-A214S, HA-V239I, HA-N328S, NA-L81P, and NA-D93G mutations, similar to those seen in the A/ Perth/16/2009 influenza strain. The HA-NSS061-063 and NNS160-162 glycosylation sites were prevalent among the 2011-2012 Guangdong strains but the NA-NRS402-404 site was deleted. Antigenically, there was a four-fold difference between A/Perth/16/2009 -like strains and the 2011-2012 Guangdong strains.
  
  
  CONCLUSIONS
  Antigenic drift of the H3N2 subtype contributed to the occurrence of the Southern China influenza epidemic of 2012.
authors.affiliation: Key Laboratory for Emergency Pathogen Detection, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China. pphuang1@163.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhong
authors.forename: Lijun
authors.initials: L
authors.lastname: Liang
authors.forename: Ping
authors.initials: P
authors.lastname: Huang
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Zhu
authors.forename: Lirong
authors.initials: L
authors.lastname: Zou
authors.forename: Shouyi
authors.initials: S
authors.lastname: Yu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hanzhong
authors.initials: H
authors.lastname: Ni
authors.forename: Jin
authors.initials: J
authors.lastname: Yan
mesh_terms: D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D058872:Epidemics; D040961:Genetic Drift; D005838:Genotype; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D008969:Molecular Sequence Data; D009154:Mutation; D009439:Neuraminidase / Q000235:genetics; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D014764:Viral Proteins / Q000235:genetics
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D012367:RNA, Viral; D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase