title: Evidence for the Introduction, Reassortment, and Persistence of Diverse Influenza A Viruses in Antarctica.
abstract: Avian influenza virus (AIV) surveillance in Antarctica during 2013 revealed the prevalence of evolutionarily distinct influenza viruses of the H11N2 subtype in Adélie penguins. Here we present results from the continued surveillance of AIV on the Antarctic Peninsula during 2014 and 2015. In addition to the continued detection of H11 subtype viruses in a snowy sheathbill during 2014, we isolated a novel H5N5 subtype virus from a chinstrap penguin during 2015. Gene sequencing and phylogenetic analysis revealed that the H11 virus detected in 2014 had a >99.1% nucleotide similarity to the H11N2 viruses isolated in 2013, suggesting the continued prevalence of this virus in Antarctica over multiple years. However, phylogenetic analysis of the H5N5 virus showed that the genome segments were recently introduced to the continent, except for the NP gene, which was similar to that in the endemic H11N2 viruses. Our analysis indicates geographically diverse origins for the H5N5 virus genes, with the majority of its genome segments derived from North American lineage viruses but the neuraminidase gene derived from a Eurasian lineage virus. In summary, we show the persistence of AIV lineages in Antarctica over multiple years, the recent introduction of gene segments from diverse regions, and reassortment between different AIV lineages in Antarctica, which together significantly increase our understanding of AIV ecology in this fragile and pristine environment.
  
  
  OBJECTIVE
  Analysis of avian influenza viruses (AIVs) detected in Antarctica reveals both the relatively recent introduction of an H5N5 AIV, predominantly of North American-like origin, and the persistence of an evolutionarily divergent H11 AIV. These data demonstrate that the flow of viruses from North America may be more common than initially thought and that, once introduced, these AIVs have the potential to be maintained within Antarctica. The future introduction of AIVs from North America into the Antarctic Peninsula is of particular concern given that highly pathogenic H5Nx viruses have recently been circulating among wild birds in parts of Canada and the Unites States following the movement of these viruses from Eurasia via migratory birds. The introduction of a highly pathogenic influenza virus in penguin colonies within Antarctica might have devastating consequences.
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Parkville, Victoria, Australia University of Melbourne, Melbourne School of Population and Global Health, Parkville, Victoria, Australia aeron.hurt@influenzacentre.org.
authors.forename: Aeron C
authors.initials: AC
authors.lastname: Hurt
authors.affiliation: Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore.
authors.forename: Yvonne C F
authors.initials: YCF
authors.lastname: Su
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Parkville, Victoria, Australia.
authors.forename: Malet
authors.initials: M
authors.lastname: Aban
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Parkville, Victoria, Australia.
authors.forename: Heidi
authors.initials: H
authors.lastname: Peck
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Parkville, Victoria, Australia.
authors.forename: Hilda
authors.initials: H
authors.lastname: Lau
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Parkville, Victoria, Australia.
authors.forename: Chantal
authors.initials: C
authors.lastname: Baas
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Parkville, Victoria, Australia.
authors.forename: Yi-Mo
authors.initials: YM
authors.lastname: Deng
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Parkville, Victoria, Australia.
authors.forename: Natalie
authors.initials: N
authors.lastname: Spirason
authors.affiliation: Zoonosis Science Center, IMBIM, Uppsala University, Uppsala, Sweden.
authors.forename: Patrik
authors.initials: P
authors.lastname: Ellström
authors.affiliation: Zoonosis Science Center, IMBIM, Uppsala University, Uppsala, Sweden Department of Microbiology, Kalmar County Hospital, Kalmar, Sweden.
authors.forename: Jorge
authors.initials: J
authors.lastname: Hernandez
authors.affiliation: Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Bjorn
authors.initials: B
authors.lastname: Olsen
authors.affiliation: WHO Collaborating Centre for Reference and Research on Influenza, Parkville, Victoria, Australia.
authors.forename: Ian G
authors.initials: IG
authors.lastname: Barr
authors.affiliation: Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore.
authors.forename: Dhanasekaran
authors.initials: D
authors.lastname: Vijaykrishna
authors.affiliation: Universidad de Concepción, Facultad de Ciencias Veterinarias, Chillán, Chile.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gonzalez-Acuna
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000821:virology; D001717:Birds / Q000821:virology; D002170:Canada; D005814:Genes, Viral / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D009980:Influenza A virus / Q000235:genetics* / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000821:virology*; D010802:Phylogeny; D046429:Spheniscidae / Q000821:virology