APPLICATION OF BIOLOGICAL AND MOLECULAR TECHNIQUES TO THE DIAGNOSIS AND CONTROL OF AVIAN INFLUENZA AND OTHER EMERGING POULTRY PATHOGENS
Location: Exotic and Emerging Avian Viral Diseases Research Unit
Title: Differences in pathogenicity and response to vaccination between Pekin and Muscovy ducks infected with H5N1 highly pathogenic influenza viruses
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 10, 2009
Publication Date: September 9, 2009
Citation: Pantin Jackwood, M.J., Kapczynski, D.R., Wasilenko, J.L., Spackman, E., Suarez, D.L. 2009. Differences in pathogenicity and response to vaccination between Pekin and Muscovy ducks infected with H5N1 highly pathogenic influenza viruses [abstract]. 5th Orthomyxovirus Research Conference, September 9-12, 2009, Freiburg, Germany. p. 34.
Ducks have been implicated in the dissemination and evolution of H5N1 highly pathogenic avian influenza (HPAI) viruses. Vaccination of domestic ducks against H5N1 HPAI is being conducted as a method of control but with mixed results. One of the observations from the field is that Muscovy ducks (Cairina moschata) respond differently to vaccination than other common domestic ducks (Anas sp.). The objective of this study was to examine the pathogenicity of H5N1 HPAI virus infection in Pekin and Muscovy ducks and compare their response to vaccination. Differences in the severity of clinical signs, antibody titers, and viral shedding after vaccination were observed between these two duck species, with Muscovy ducks presenting less protection after vaccination and longer duration of virus shedding. To better understand the cause of the differences observed we examined host responses to infection in vaccinated and non-vaccinated ducks. Relative real-time reverse transcriptase polymerase chain reaction (RT-PCR) was used to determine the expression of innate immune related genes. Among the genes commonly up-regulated after virus infection were IL-6, MIP-1b, MIP-3b, MHCI, and MX1; however levels of expression were not the same between the two duck species. Among the genes that were down-regulated were MHCII, IL8 and TLR7. Other genes were expressed differently depending on the species of the ducks, including IL-1, and IFN. The gene expression response was also different between vaccinated Pekin and Muscovy ducks. In conclusion, differences in the innate immune response between Pekin and Muscovy ducks may explain the differences observed in response to vaccination. This information should be taken into account when implementing vaccine strategies for control of HPAI in different bird species.