title: Novel triple reassortant H1N2 influenza viruses bearing six internal genes of the pandemic 2009/H1N1 influenza virus were detected in pigs in China.
abstract: BACKGROUND
  The pandemic A/H1N1 influenza viruses emerged in both Mexico and the United States in March 2009, and were transmitted efficiently in the human population. Transmissions of the pandemic 2009/H1N1 virus from humans to poultry and other species of mammals were reported from several continents during the course of the 2009 H1N1 pandemic. Reassortant H1N1, H1N2, and H3N2 viruses containing genes of the pandemic 2009/H1N1 viruses appeared in pigs in some countries.
  
  
  METHODS
  In winter of 2012, a total of 2600 nasal swabs were collected from healthy pigs in slaughterhouses located throughout 10 provinces in China. The isolated viruses were subjected to genetic and antigenic analysis. Two novel triple-reassortant H1N2 influenza viruses were isolated from swine in China in 2012, with the HA gene derived from Eurasian avian-like swine H1N1, the NA gene from North American swine H1N2, and the six internal genes from the pandemic 2009/H1N1 viruses. The two viruses had similar antigenic features and some significant changes in antigenic characteristics emerged when compared to the previously identified isolates.
  
  
  CONCLUSIONS
  We inferred that the novel reassortant viruses in China may have arisen from the accumulation of the three types of influenza viruses, which further indicates that swine herds serve as "mixing vessels" for influenza viruses. Influenza virus reassortment is an ongoing process, and our findings highlight the urgent need for continued influenza surveillance among swine herds.
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Chuanling
authors.initials: C
authors.lastname: Qiao
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Liping
authors.initials: L
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Huanliang
authors.initials: H
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Huiyang
authors.initials: H
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China. Electronic address: chenhualan@caas.cn.
authors.forename: Hualan
authors.initials: H
authors.lastname: Chen
mesh_terms: D000818:Animals; D002681:China; D005814:Genes, Viral; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics*; D057221:Influenza A Virus, H1N2 Subtype / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D009297:Nasal Mucosa / Q000821:virology; D009976:Orthomyxoviridae Infections / Q000662:veterinary* / Q000821:virology; D016865:Reassortant Viruses / Q000235:genetics / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D013552:Swine / Q000821:virology*
keywords: Genetic analysis; H1N2; Novel reassortant; Swine influenza virus