title: Transmission of influenza A(H1N1) 2009 pandemic viruses in Australian swine.
abstract: BACKGROUND
  Swine have receptors for both human and avian influenza viruses and are a natural host for influenza A viruses. The 2009 influenza A(H1N1) pandemic (H1N1pdm) virus that was derived from avian, human and swine influenza viruses has infected pigs in various countries.
  
  
  OBJECTIVE
  To investigate the relationship between the H1N1pdm viruses isolated from piggery outbreaks in Australia and human samples associated with one of the outbreaks by phylogenetic analysis, and to determine whether there was any reassortment event occurring during the human-pig interspecies transmission.
  
  
  METHODS
  Real-time RT-PCR and full genome sequencing were carried out on RNA isolated from nasal swabs and/or virus cultures. Phylogenetic analysis was performed using the Geneious package.
  
  
  RESULTS
  The influenza H1N1pdm outbreaks were detected in three pig farms located in three different states in Australia. Further analysis of the Queensland outbreak led to the identification of two distinct virus strains in the pigs. Two staff working in the same piggery were also infected with the same two strains found in the pigs. Full genome sequence analysis on the viruses isolated from pigs and humans did not identify any reassortment of these H1N1pdm viruses with seasonal or avian influenza A viruses.
  
  
  CONCLUSIONS
  This is the first report of swine infected with influenza in Australia and marked the end of the influenza-free era for the Australian swine industry. Although no reassortment was detected in these cases, the ability of these viruses to cross between pigs and humans highlights the importance of monitoring swine for novel influenza infections.
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, VIDRL, Melbourne, Victoria, Australia. yi-mo.deng@influenzacentre.org
authors.forename: Yi-Mo
authors.initials: YM
authors.lastname: Deng
authors.forename: Pina
authors.initials: P
authors.lastname: Iannello
authors.forename: Ina
authors.initials: I
authors.lastname: Smith
authors.forename: James
authors.initials: J
authors.lastname: Watson
authors.forename: Ian G
authors.initials: IG
authors.lastname: Barr
authors.forename: Peter
authors.initials: P
authors.lastname: Daniels
authors.forename: Naomi
authors.initials: N
authors.lastname: Komadina
authors.forename: Bruce
authors.initials: B
authors.lastname: Harrower
authors.forename: Frank Y K
authors.initials: FY
authors.lastname: Wong
mesh_terms: D000818:Animals; D001315:Australia / Q000453:epidemiology; D004196:Disease Outbreaks; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000635:transmission* / Q000821:virology*; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D058873:Pandemics / Q000662:veterinary; D010802:Phylogeny; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000635:transmission* / Q000821:virology*
chemical_list: C543345:H1N1 virus hemagglutinin; D019267:Hemagglutinin Glycoproteins, Influenza Virus