tetano
Editor, Senior Moderator
[h=1]The enigma of the apparent disappearance of Eurasian highly pathogenic H5 clade 2.3.4.4 influenza A viruses in North American waterfowl[/h]
[h=2]Significance[/h] The role of wild aquatic birds in perpetuating highly pathogenic avian influenza viruses (HPAIVs) is unresolved. We examined whether the subtype H5 clade 2.3.4.4 HPAIV that devastated the US poultry industry in 2015 is perpetuated in wild aquatic birds. Virologic surveillance in 2014/15 and over the previous 43 y failed to detect HPAIVs in wild aquatic birds before or after the poultry outbreak, supporting the premise that there are unresolved mechanisms preventing wild aquatic birds from perpetuating HPAIVs. The significance of these findings is that timely and efficient strategies used to successfully prevent and eradicate HPAIVs infecting poultry, without the use of vaccines, appear to complement natural biological mechanisms in disrupting the perpetuation and possible spread of HPAIVs by wild aquatic birds.
[h=2]Abstract[/h] One of the major unresolved questions in influenza A virus (IAV) ecology is exemplified by the apparent disappearance of highly pathogenic (HP) H5N1, H5N2, and H5N8 (H5Nx) viruses containing the Eurasian hemagglutinin 2.3.4.4 clade from wild bird populations in North America. The introduction of Eurasian lineage HP H5 clade 2.3.4.4 H5N8 IAV and subsequent reassortment with low-pathogenic H?N2 and H?N1 North American wild bird-origin IAVs in late 2014 resulted in widespread HP H5Nx IAV infections and outbreaks in poultry and wild birds across two-thirds of North America starting in November 2014 and continuing through June 2015. Although the stamping out strategies adopted by the poultry industry and animal health authorities in Canada and the United States?which included culling, quarantining, increased biosecurity, and abstention from vaccine use?were successful in eradicating the HP H5Nx viruses from poultry, these activities do not explain the apparent disappearance of these viruses from migratory waterfowl. Here we examine current and historical aquatic bird IAV surveillance and outbreaks of HP H5Nx in poultry in the United States and Canada, providing additional evidence of unresolved mechanisms that restrict the emergence and perpetuation of HP avian influenza viruses in these natural reservoirs.
http://www.pnas.org/content/113/32/9033.abstract
- Scott Krauss[SUP]a[/SUP],
- David E. Stallknecht[SUP]b[/SUP],
- Richard D. Slemons[SUP]c[/SUP],
- Andrew S. Bowman[SUP]c[/SUP],
- Rebecca L. Poulson[SUP]b[/SUP],
- Jacqueline M. Nolting[SUP]c[/SUP],
- James P. Knowles[SUP]a[/SUP], and
- Robert G. Webster[SUP]a[/SUP],[SUP]1[/SUP]
- Contributed by Robert G. Webster, June 7, 2016 (sent for review February 24, 2016; reviewed by Ruben Donis, Thijs Kuiken, and David E. Swayne)
- Abstract
- Full Text
- Authors & Info
- Figures
- Metrics
- Related Content
[h=2]Significance[/h] The role of wild aquatic birds in perpetuating highly pathogenic avian influenza viruses (HPAIVs) is unresolved. We examined whether the subtype H5 clade 2.3.4.4 HPAIV that devastated the US poultry industry in 2015 is perpetuated in wild aquatic birds. Virologic surveillance in 2014/15 and over the previous 43 y failed to detect HPAIVs in wild aquatic birds before or after the poultry outbreak, supporting the premise that there are unresolved mechanisms preventing wild aquatic birds from perpetuating HPAIVs. The significance of these findings is that timely and efficient strategies used to successfully prevent and eradicate HPAIVs infecting poultry, without the use of vaccines, appear to complement natural biological mechanisms in disrupting the perpetuation and possible spread of HPAIVs by wild aquatic birds.
[h=2]Abstract[/h] One of the major unresolved questions in influenza A virus (IAV) ecology is exemplified by the apparent disappearance of highly pathogenic (HP) H5N1, H5N2, and H5N8 (H5Nx) viruses containing the Eurasian hemagglutinin 2.3.4.4 clade from wild bird populations in North America. The introduction of Eurasian lineage HP H5 clade 2.3.4.4 H5N8 IAV and subsequent reassortment with low-pathogenic H?N2 and H?N1 North American wild bird-origin IAVs in late 2014 resulted in widespread HP H5Nx IAV infections and outbreaks in poultry and wild birds across two-thirds of North America starting in November 2014 and continuing through June 2015. Although the stamping out strategies adopted by the poultry industry and animal health authorities in Canada and the United States?which included culling, quarantining, increased biosecurity, and abstention from vaccine use?were successful in eradicating the HP H5Nx viruses from poultry, these activities do not explain the apparent disappearance of these viruses from migratory waterfowl. Here we examine current and historical aquatic bird IAV surveillance and outbreaks of HP H5Nx in poultry in the United States and Canada, providing additional evidence of unresolved mechanisms that restrict the emergence and perpetuation of HP avian influenza viruses in these natural reservoirs.
http://www.pnas.org/content/113/32/9033.abstract