title: Reassortant between human-Like H3N2 and avian H5 subtype influenza A viruses in pigs: a potential public health risk.
abstract: BACKGROUND
  Human-like H3N2 influenza viruses have repeatedly been transmitted to domestic pigs in different regions of the world, but it is still uncertain whether any of these variants could become established in pig populations. The fact that different subtypes of influenza viruses have been detected in pigs makes them an ideal candidate for the genesis of a possible reassortant virus with both human and avian origins. However, the determination of whether pigs can act as a "mixing vessel" for a possible future pandemic virus is still pending an answer. This prompted us to gather the epidemiological information and investigate the genetic evolution of swine influenza viruses in Jilin, China.
  
  
  METHODS
  Nasopharyngeal swabs were collected from pigs with respiratory illness in Jilin province, China from July 2007 to October 2008. All samples were screened for influenza A viruses. Three H3N2 swine influenza virus isolates were analyzed genetically and phylogenetically.
  
  
  RESULTS
  Influenza surveillance of pigs in Jilin province, China revealed that H3N2 influenza viruses were regularly detected from domestic pigs during 2007 to 2008. Phylogenetic analysis revealed that two distinguishable groups of H3N2 influenza viruses were present in pigs: the wholly contemporary human-like H3N2 viruses (represented by the Moscow/10/99-like sublineage) and double-reassortant viruses containing genes from contemporary human H3N2 viruses and avian H5 viruses, both co-circulating in pig populations.
  
  
  CONCLUSIONS
  The present study reports for the first time the coexistence of wholly human-like H3N2 viruses and double-reassortant viruses that have emerged in pigs in Jilin, China. It provides updated information on the role of pigs in interspecies transmission and genetic reassortment of influenza viruses.
authors.affiliation: College of Animal Science and Veterinary Medicine, Jilin University, Changchun, Jilin, China. congyanlong@126.com
authors.forename: Yanlong
authors.initials: Y
authors.lastname: Cong
authors.forename: Guangmei
authors.initials: G
authors.lastname: Wang
authors.forename: Zhenhong
authors.initials: Z
authors.lastname: Guan
authors.forename: Shuang
authors.initials: S
authors.lastname: Chang
authors.forename: Quanpeng
authors.initials: Q
authors.lastname: Zhang
authors.forename: Guilian
authors.initials: G
authors.lastname: Yang
authors.forename: Weili
authors.initials: W
authors.lastname: Wang
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Meng
authors.forename: Weiming
authors.initials: W
authors.lastname: Ren
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Wang
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Ding
mesh_terms: D000818:Animals; D002460:Cell Line; D002681:China / Q000453:epidemiology; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D053124:Influenza A Virus, H5N1 Subtype / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology / Q000821:virology; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D016865:Reassortant Viruses / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D016415:Sequence Alignment; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000821:virology*
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus