title: [Phylogenetic analysis based on hemagglutinin and neuraminidase genes between swine influenza virus and human influenza A/H3N2 virus strains isolated in Zhejiang province].
abstract: OBJECTIVE
  To investigate the phylogenetic relationship between swine influenza A/H3N2 virus and the representative strains of human influenza A/H3N2 virus isolated in two epidemics in recent years through comparing the sequences within HA and NA genes.
  
  
  METHODS
  HA and NA gene of the human representative strains were sequenced, and then phylogenetic tree with the swine and human strains isolated in the corresponding period of time were constructed.
  
  
  RESULTS
  The homologies on the HA1 domain between human representative strains (A/Zhejiang/10/98, A/Zhejiang/6/99 and A/Zhejiang/8/02)and the swine strains (A/SW/Ontario/130/97, A/SW/Hongkong/4361/99 and A/SW/Hongkong/74/02) were 99.1%, 99.4% and 99.4% respectively. Based on the NA gene, the homologies between human strains (A/Zhejiang/10/98, _A/Zhejiang/6/99 and A/Zhejiang/8/02)and the swine strains (A/SW/Ontario/130/97, A/SW/Hongkong/4361/99 and A/SW/Hongkong/74/02) were 98.2%, 99.3% and 99.3% respectively. The results showed that the two types of influenza viruses were highly homologue, and even some of their homologies were higher than that amongst the contemporary human influenza A/H3N2 strains. The same results shown in the phylogenetic tree.
  
  
  CONCLUSIONS
  The human influenza A/H3N2 virus isolates in the two epidemic closely associated with some of the swine influenza virus strains, and their relationship should be further studied.
authors.affiliation: Ningbo University Medical School, Ningbo 315040, Zhejiang, China.
authors.forename: Li-pei
authors.initials: LP
authors.lastname: Qiu
authors.forename: Yi-yu
authors.initials: YY
authors.lastname: Lu
authors.forename: Chang-ping
authors.initials: CP
authors.lastname: Xu
mesh_terms: D000818:Animals; D002681:China; 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 / Q000517:prevention & control; D009439:Neuraminidase / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013552:Swine / Q000821:virology*
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D009439:Neuraminidase