|To, Thanh Long|
Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2011
Publication Date: 9/1/2011
Citation: Cagle, C.A., To, T., Nguyen, T., Wasilenko, J.L., Adams, S.C., Cardona, C.J., Spackman, E., Suarez, D.L., Pantin Jackwood, M.J. 2011. Pekin and Muscovy ducks respond differently to vaccination with a H5N1 highly pathogenic avian influenza (HPAI) commercial inactivated vaccine. Vaccine. 29(38):6549-6557. Interpretive Summary: Highly pathogenic avian influenza (HPAI) subtype H5N1 virus infections are constantly monitored worldwide because of their devastating effects on poultry. Ducks have been implicated in the dissemination and evolution of H5N1 HPAI viruses. Domestic ducks that are in contact with wild waterfowl and poultry function as key intermediates in the transmission of avian influenza and therefore are included in vaccination programs. Although vaccination has proven effective in protecting ducks against disease, different species of domestic ducks appear to respond differently to vaccination. In this study we compared the response to vaccination between two common domestic duck species, Pekin and Muscovy. Clear differences in response to vaccination were observed between these two duck species. Additionally, differences were also observed in clinical disease after infection with a H5N1 HPAI virus, and the ducks innate immune responses also differed. These results should be taken into account when developing effective vaccination programs for controlling HPAI in different species of ducks, since we demonstrated that not all duck species respond equally to avian influenza vaccination.
Technical Abstract: Domestic ducks are key intermediates in the transmission of H5N1 highly pathogenic avian influenza (HPAI) viruses, and therefore are included in vaccination programs to control H5N1 HPAI. Although vaccination has proven effective in protecting ducks against disease, different species of domestic ducks appear to respond differently to vaccination, and shedding of the virus may still occur in clinically healthy vaccinated populations. In this study we compared the response to vaccination between two common domestic duck species, Pekin and Muscovy, which were vaccinated using one of three different schedules in order to obtain protection to H5N1 HPAI before one month of age. Clear differences in response to vaccination were observed, with the Muscovy ducks presenting lower viral antibody titers induced by vaccination and higher number of sick and dead ducks after challenge with a H5N1 HPAI virus. When comparing the response to infection in non-vaccinated ducks, differences were also observed, with infected Muscovy ducks presenting a lower mean death time and more severe neurological signs than Pekin ducks. However Pekin ducks had significant higher body temperatures and higher levels of nitric oxide in blood at 2 days post challenge than Muscovy ducks, indicating possible differences in innate immune responses. Comparison of the expression of innate immune related genes in spleens of the challenged ducks, showed differences including higher levels of expression of RIG1 and MX1 in Pekin ducks, and higher levels of expression of IL6 and chemokine MIP3b. Both duck species showed an up-regulation of IFNalpha and MHCI expression, and a down-regulation of MHCII. In conclusion, differences in response to infection and vaccination were observed between the two domestic duck species. This information is important and should be taken into account when developing effective vaccination programs for controlling HPAI in different species of ducks.