North Atlantic Migratory Bird Flyways Provide Routes for Intercontinental Movement of Avian Influenza Viruses

Robert J Dusek,Timothy B Stockwell,Gunnar T Hallgrimsson,Xudong Lin,Jón E Jónsson,Joshua L Teslaa,Sean W Nashold,Srinand Sreevatsan,Vivien G Dugan,Shinichiro Enomoto,Nadia Fedorova,David E Wentworth,Jeffrey S Hall,Hon S Ip,Rebecca A Halpin,Dhanasekaran Vijaykrishna

doi:10.1371/journal.pone.0092075

Abstract

Avian influenza virus (AIV) in wild birds has been of increasing interest over the last decade due to the emergence of AIVs that cause significant disease and mortality in both poultry and humans. While research clearly demonstrates that AIVs can move across the Pacific or Atlantic Ocean, there has been no data to support the mechanism of how this occurs. In spring and autumn of 2010 and autumn of 2011 we obtained cloacal swab samples from 1078 waterfowl, gulls, and shorebirds of various species in southwest and west Iceland and tested them for AIV. From these, we isolated and fully sequenced the genomes of 29 AIVs from wild caught gulls (Charadriiformes) and waterfowl (Anseriformes) in Iceland. We detected viruses that were entirely (8 of 8 genomic segments) of American lineage, viruses that were entirely of Eurasian lineage, and viruses with mixed American-Eurasian lineage. Prior to this work only 2 AIVs had been reported from wild birds in Iceland and only the sequence from one segment was available in GenBank. This is the first report of finding AIVs of entirely American lineage and Eurasian lineage, as well as reassortant viruses, together in the same geographic location. Our study demonstrates the importance of the North Atlantic as a corridor for the movement of AIVs between Europe and North America.

Highlights

Avian influenza viruses (AIV) are commonly found in wild waterfowl, shorebirds and gulls around the world
Highly pathogenic (HP) AIVs have rarely been seen in wild birds, but since 1997 when HPAIV H5N1 began circulating among domestic waterfowl and terrestrial birds primarily in southeast Asia, mortality events affecting wild birds due to this disease have been extensively documented [3,4]
The remaining virus subtypes were detected in various gull species, including black-headed gull (Chroicocephalus ridibundus), lesser black-backed gull (Larus fuscus), great black-backed gull (Larus marinus), glaucous gull (Larus hyperboreus), herring gull (Larus argentatus), Iceland gull (Larus glaucoides), and a single hybrid glaucous x herring gull (Larus hyperboreus x Larus argentatus, Table S1)

Summary

Introduction

Avian influenza viruses (AIV) are commonly found in wild waterfowl, shorebirds and gulls around the world. Highly pathogenic (HP) AIVs have rarely been seen in wild birds, but since 1997 when HPAIV H5N1 began circulating among domestic waterfowl and terrestrial birds primarily in southeast Asia, mortality events affecting wild birds due to this disease have been extensively documented [3,4]. AIVs are segmented negative sense RNA viruses consisting of 8 genomic RNA segments, comprising 6 internal protein coding segments (polymerase basic 2 (PB2), polymerase basic 1 (PB1), polymerase acidic (PA), nucleoprotein (NP), matrix (M), and nonstructural (NS)) and 2 segments encoding surface glycoproteins (hemagglutinin (HA) and neuraminidase (NA)). The remaining 5 internal protein coding segments are highly conserved with the extent of diversity in these segments less than that found within an HA or NA subtype [12]

Methods

Results

Conclusion