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United States Department of Agriculture

Agricultural Research Service

Research Project: Intervention Strategies to Control and Prevent Disease Outbreaks Caused by Avian Influenza and Other Emerging Poultry Pathogens

Location: Exotic and Emerging Avian Viral Diseases Research Unit

Title: Changing pathobiology of H5N1 highly pathogenic avian influenza (HPAI) viruses in domestic waterfowl

Authors
item PANTIN-JACKWOOD, MARY
item SWAYNE, DAVID
item SUAREZ, DAVID
item Wasilenko, Jamie
item SMITH, DIANE
item SHEPHERD, ERIC

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 2011
Publication Date: April 1, 2012
Citation: Pantin Jackwood, M.J., Swayne, D.E., Suarez, D.L., Wasilenko, J.L., Smith, D.M., Shepherd, E.M. 2012. Changing pathobiology of H5N1 highly pathogenic avian influenza (HPAI) viruses in domestic waterfowl. Meeting Abstract. p.51.

Interpretive Summary: The Eurasian-African lineage of H5N1 highly pathogenic avian influenza (HPAI) viruses has evolved into many genetic lineages and multiple sublineages. The divergent strains that have arisen express distinct pathobiological features and increased virulence for many bird species including domestic waterfowl. Since 2002, a number of H5N1 HPAI viruses have been shown to cause disease and death in domestic ducks; but the level of pathogenicity observed is not consistent among different H5N1 HPAI viruses and the age and species of the domestic ducks appears to affect the outcome of the infection. By pathotyping more than 40 H5N1 viruses in the Pekin duck (Anas platyrhinchos) model we have shown the large variation in pathogenicity among H5N1 HPAI viruses, with certain HA clade viruses being less pathogenic for ducks (clades 2.1 and 7) and other HA clade viruses showing a great variation in pathogenicity (clades 1 and 2.2.1.). The pathogenicity of the H5N1 viruses also varies between the two farmed duck species, with Muscovy ducks (Cairina moschata) being the most susceptible to disease, followed by various breeds of domestic ducks (Anas platyrhinchos) Pekin, Black Runners, Mallards, Rouen and Khaki Campbell ducks. Differences are also observed in response to H5N1 vaccination, with Muscovy ducks showing less protection after vaccination than Pekin ducks. The determinants of pathogenicity of H5N1 HPAI viruses have been well studied in mammals; however, the factors contributing to increased pathogenicity in ducks have not been well characterized. With the use of single-gene reassortant viruses with genes from H5N1 HPAI viruses of different pathogenicity we found that in some cases exchanging the HA gene was enough to increase virulence, but in other cases it was not, with other genes, including the NA, NS and polymerase complex genes, also affecting the pathogenicity of the virus.

Technical Abstract: The Eurasian-African lineage of H5N1 highly pathogenic avian influenza (HPAI) viruses has evolved into many genetic lineages and multiple sublineages. The divergent strains that have arisen express distinct pathobiological features and increased virulence for many bird species including domestic waterfowl. Since 2002, a number of H5N1 HPAI viruses have been shown to cause disease and death in domestic ducks; but the level of pathogenicity observed is not consistent among different H5N1 HPAI viruses and the age and species of the domestic ducks appears to affect the outcome of the infection. By pathotyping more than 40 H5N1 viruses in the Pekin duck (Anas platyrhinchos) model we have shown the large variation in pathogenicity among H5N1 HPAI viruses, with certain HA clade viruses being less pathogenic for ducks (clades 2.1 and 7) and other HA clade viruses showing a great variation in pathogenicity (clades 1 and 2.2.1.). The pathogenicity of the H5N1 viruses also varies between the two farmed duck species, with Muscovy ducks (Cairina moschata) being the most susceptible to disease, followed by various breeds of domestic ducks (Anas platyrhinchos) Pekin, Black Runners, Mallards, Rouen and Khaki Campbell ducks. Differences are also observed in response to H5N1 vaccination, with Muscovy ducks showing less protection after vaccination than Pekin ducks. The determinants of pathogenicity of H5N1 HPAI viruses have been well studied in mammals; however, the factors contributing to increased pathogenicity in ducks have not been well characterized. With the use of single-gene reassortant viruses with genes from H5N1 HPAI viruses of different pathogenicity we found that in some cases exchanging the HA gene was enough to increase virulence, but in other cases it was not, with other genes, including the NA, NS and polymerase complex genes, also affecting the pathogenicity of the virus.

Last Modified: 9/10/2014
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