Long-term surveillance of H7 influenza viruses in American wild aquatic birds: Are the H7N3 influenza viruses in wild birds the precursors of highly pathogenic strains in domestic poultry?

Scott Krauss, Karla M. Stucker, Seth A. Schobel, Angela Danner, Kimberly Friedman, James P. Knowles, Ghazi Kayali, Lawrence J. Niles, Amanda D. Dey, Garnet Raven, Paul Pryor, Xudong Lin, Suman R. Das, Timothy B. Stockwell, David E. Wentworth*, Robert G. Webster

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

The emergence of influenza A virus (IAV) in domestic avian species and associated transmissions to mammals is unpredictable. In the Americas, the H7 IAVs are of particular concern, and there have been four separate outbreaks of highly pathogenic (HP) H7N3 in domestic poultry in North and South America between 2002 and 2012, with occasional spillover into humans. Here, we use long-term IAV surveillance in North American shorebirds at Delaware Bay, USA, from 1985 to 2012 and in ducks in Alberta, Canada, from 1976 to 2012 to determine which hemagglutinin (HA)-neuraminidase (NA) combinations predominated in Anseriformes (ducks) and Charadriiformes (shorebirds) and whether there is concordance between peaks of H7 prevalence and transmission in wild aquatic birds and the emergence of H7 IAVs in poultry and humans. Whole-genome sequencing supported phylogenetic and genomic constellation analyses to determine whether HP IAVs emerge in the context of specific internal gene segment sequences. Phylogenetic analysis of whole-genome sequences of the H7N3 influenza viruses from wild birds and HP H7N3 outbreaks in the Americas indicate that each HP outbreak was an independent emergence event and that the low pathogenic (LP) avian influenza precursors were most likely from dabbling ducks. The different polybasic cleavage sites in the four HP outbreaks support independent origins. At the 95% nucleotide percent identity-level phylogenetic analysis showed that the wild duck HA, PB1, and M sequences clustered with the poultry and human outbreak sequences. The genomic constellation analysis strongly suggests that gene segments/virus flow from wild birds to domestic poultry.

Original languageEnglish
Article numbere35
JournalEmerging Microbes and Infections
Volume4
Issue number6
DOIs
StatePublished - 17 Jun 2015
Externally publishedYes

Keywords

  • American wild birds
  • Anseriforme
  • Avian influenza
  • Charadriiforme
  • H7
  • Highly pathogenic avian influenza
  • Surveillance

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