title: Genetic correlation between H3N2 human and swine influenza viruses.
abstract: BACKGROUND
  H3N2 is one of the main subtypes of influenza virus which circulates in human and swine population throughout the world.
  
  
  OBJECTIVE
  To investigate the genetic correlation between H3N2 human and swine influenza viruses from the same region during the same season.
  
  
  METHODS
  Five H3N2 human and four H3N2 swine influenza viruses were isolated from Guangdong province of China in the winter of 2005. The molecular evolution of eight gene segments was analyzed.
  
  
  RESULTS
  In the phylogenetic trees of gene segments, all H3N2 human isolates along with the 2000's human isolates formed a cluster, and most of the H3N2 swine isolates along with the 1990's human isolates formed another cluster except that the M and NS gene of A/Swine/Guangdong/01/2005 and the PA gene of A/Swine/Guangdong/02/2005 fell into the cluster of the classical swine influenza virus, indicating the reassortment between H3N2 human and H1N1 swine influenza viruses.
  
  
  CONCLUSIONS
  In this study, H3N2 swine influenza viruses in 2005 did not originate from the 2000's H3N2 human influenza viruses, but from the 1990's H3N2 human isolates. In addition, the reassortment of H3N2 human and H1N1 swine influenza virus in pigs was common in recent years.
authors.affiliation: Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.forename: Guihong
authors.initials: G
authors.lastname: Zhang
authors.forename: Yuelong
authors.initials: Y
authors.lastname: Shu
authors.forename: Xuemei
authors.initials: X
authors.lastname: Chen
authors.forename: Yiping
authors.initials: Y
authors.lastname: Zhu
authors.forename: Limin
authors.initials: L
authors.lastname: Yang
authors.forename: Guangpeng
authors.initials: G
authors.lastname: Ma
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Wenjun
authors.initials: W
authors.lastname: Liu
mesh_terms: D000818:Animals; D002681:China; D016000:Cluster Analysis; D019143:Evolution, Molecular; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics; D053122:Influenza A Virus, H3N2 Subtype / Q000235:genetics* / Q000302:isolation & purification; D007251:Influenza, Human / Q000821:virology*; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D016865:Reassortant Viruses / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013552:Swine; D013553:Swine Diseases / Q000821:virology*
chemical_list: D012367:RNA, Viral