More bird flu found in Antarctic penguins

[Gert van der Hoek]

The discovery of a new strain of bird flu in Antarctic penguins has raised concerns the virus is reaching the frozen continent more often than previously thought, flown in by migratory birds.

Australian researchers helped uncover the new strain of avian influenza in the chinstrap penguin in 2015, finding striking similarities to a North American strain, which meant it had only been introduced to Antarctica recently.

The virus was first detected in Antarctica in 2013, but the discovery of the new strain has raised a red flag to the vulnerability of penguins to avian flu and its capacity to reach Antarctica.


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[Gert van der Hoek]

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J Virol. 2016 Aug 17. pii: JVI.01404-16. [Epub ahead of print]

[h=1]Evidence for the introduction, reassortment and persistence of diverse influenza A viruses in Antarctica.[/h] Hurt AC1, Su YC2, Aban M3, Peck H3, Lau H3, Baas C3, Deng YM3, Spirason N3, Ellstr?m P4, Hernandez J5, Olsen B6, Barr IG3,Vijaykrishna D2, Gonzalez-Acuna D7.
[h=3]Abstract[/h]
Avian influenza virus (AIV) surveillance in Antarctica during 2013 revealed the prevalence of evolutionarily distinct influenzaviruses of H11N2 subtype in Ad?lie 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 during 2014 in a snowy sheathbill, we isolated a novel H5N5 subtype virus during 2015 in a chinstrap penguin. 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 continued prevalence of this virus over multiple years in Antarctica.

However, phylogenetic analysis of the H5N5 virus showed that their genome segments were recently introduced into the continent, except for the NP gene that 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 over multiple years in Antarctica; recent introduction of gene segments from diverse regions; and reassortment between different AIV lineages in Antarctica, which together, significantly increases our understanding of AIV ecology in this fragile and pristine environment.

[h=4]IMPORTANCE:[/h] Analysis of avian influenza viruses (AIVs) detected in Antarctica reve
als both the relatively recent introduction of an H5N5 AIV predominantly of North American-like origin, as well as 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 amongst 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 into penguin colonies within Antarctica might have devastating consequences.