title: Analysis of influenza A viruses of subtype H1 from wild birds, turkeys and pigs in Germany reveals interspecies transmission events.
abstract: BACKGROUND
  Despite considerable host species barriers, interspecies transmissions of influenza A viruses between wild birds, poultry and pigs have been demonstrated repeatedly. In particular, viruses of the subtypes H1 and H3 were transmitted between pigs and poultry, predominantly turkeys, in regions with a high population density of both species. The recovery of a swine influenza H1N1 virus from a turkey flock in Germany in 2009 prompted us to investigate molecularly the subtype H1 viruses recently detected in wild birds, pigs and poultry.
  
  
  OBJECTIVE
  The goal of this study was to investigate the relationship between H1N1 viruses originating from wild and domestic animals of Germany and to identify potential trans-species transmission or reassortment events.
  
  
  METHODS
  Hemagglutinin and neuraminidase gene or full-length genome sequences were generated from selected, current H1N1 viruses from wild birds, pigs and turkeys. Phylogenetic analyses were combined with genotyping and analyses of the deduced amino acid sequences with respect to biologically active sites. Antigenic relationships were assessed by hemagglutination inhibition reactions.
  
  
  RESULTS
  Phylogenetic analysis of the hemagglutinin sequences showed that viruses from distinct H1 subgroups co-circulate among domestic animals and wild birds. In addition, these viruses comprised different genotypes and were distinguishable antigenically. An H1N1 virus isolated from a turkey farm in northern Germany in 2009 showed the highest similarity with the avian-like porcine H1N1 influenza viruses circulating in Europe since the late 1970s.
  
  
  CONCLUSIONS
  The data demonstrate the genetic and antigenic heterogeneity of H1 viruses currently circulating in domestic and wild animals in Germany and points to turkeys as a possible bridge between avian and mammalian hosts.
authors.affiliation: Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany. elke.starick@fli.bund.de
authors.forename: Elke
authors.initials: E
authors.lastname: Starick
authors.forename: Sasan R
authors.initials: SR
authors.lastname: Fereidouni
authors.forename: Elke
authors.initials: E
authors.lastname: Lange
authors.forename: Christian
authors.initials: C
authors.lastname: Grund
authors.forename: Thomas
authors.initials: T
authors.lastname: Vahlenkamp
authors.forename: Martin
authors.initials: M
authors.lastname: Beer
authors.forename: Timm C
authors.initials: TC
authors.lastname: Harder
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000835:Animals, Wild / Q000821:virology*; D000914:Antibodies, Viral / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology; D016000:Cluster Analysis; D014644:Genetic Variation; D005838:Genotype; D005858:Germany; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000635:transmission* / Q000821:virology; D009439:Neuraminidase / Q000235:genetics; D009976:Orthomyxoviridae Infections / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013552:Swine / Q000821:virology*; D013553:Swine Diseases / Q000635:transmission* / Q000821:virology; D014422:Turkeys / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; C543345:H1N1 virus hemagglutinin; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase