title: Two genotypes of H1N2 swine influenza viruses appeared among pigs in China.
abstract: BACKGROUND
  H1N2 is one of the main subtypes of influenza, which circulates in swine all over the world.
  
  
  OBJECTIVE
  To investigate the prevalence and genetic of H1N2 in swine of China.
  
  
  METHODS
  Two H1N2 swine influenza viruses were isolated from Tianjin and Guangdong province of China in 2004 and 2006, respectively. The molecular evolution of eight gene segments was analyzed.
  
  
  RESULTS
  A/Swine/Tianjin/1/2004 has low identity with A/Swine/Guangdong/2006; in the phylogenetic tree of PA gene, A/Swine/Guangdong/1/2006 and A/Swine/Guangxi/1/2006 along with the H1N2 swine isolates of North America formed a cluster; and A/Swine/Tianjin/2004 and A/Swine/Zhejiang/2004, along with the classical H1N1 swine isolates formed another cluster; except that NA gene of A/Swine/Tianjin/1/2004 fell into the cluster of the H3N2 human influenza virus, indicating the reassortment between H3N2 human and H1N1 swine influenza viruses.
  
  
  CONCLUSIONS
  Two different genotypes of H1N2 appeared among pigs in China. A/swine/Guangdong/1/06 was probably from H1N2 swine influenza viruses of North America; while A/swine/Tianjin/1/04 maybe come from reassortments of classical H1N1 swine and H3N2 human viruses prevalent in North America.
authors.affiliation: Animal Influenza Laboratory of the Ministry of Agriculture and National Key Laborattory of Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
authors.forename: Chuantian
authors.initials: C
authors.lastname: Xu
authors.forename: Qiyun
authors.initials: Q
authors.lastname: Zhu
authors.forename: Huanliang
authors.initials: H
authors.lastname: Yang
authors.forename: Xiumei
authors.initials: X
authors.lastname: Zhang
authors.forename: Chuanling
authors.initials: C
authors.lastname: Qiao
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Xin
authors.forename: Hualan
authors.initials: H
authors.lastname: Chen
mesh_terms: D000818:Animals; D002681:China; D003430:Cross-Sectional Studies; D019143:Evolution, Molecular; D005838:Genotype; D057221:Influenza A Virus, H1N2 Subtype / Q000235:genetics*; D009296:Nasal Cavity / Q000821:virology; D009976:Orthomyxoviridae Infections / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D013552:Swine; D013553:Swine Diseases / Q000821:virology*