|Bertran, Kateri - US Department Of Agriculture (USDA)|
Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2014
Publication Date: 7/25/2014
Citation: Bertran, K., Swayne, D.E. 2014. Impact of vaccination on infection with Vietnam H5N1 high pathogenicity avian influenza virus in hens and the eggs they lay [abstract]. In: Abstracts of 2014 Annual Meeting of the American Association of Avian Pathologists (AAAP) Annual Meeting, July 26-29, 2014, Denver, Colorado. CDROM.
Technical Abstract: Highly pathogenic avian influenza virus (HPAIV) infections in chickens produce a negative impact on egg production, and virus is deposited on surface and internal contents of eggs. Previously, vaccination maintained egg production and reduced egg contamination when challenged with a North American H5N2 HPAIV. However, Asian H5N1 HPAIV infected hens have a higher rate of egg contamination and higher levels of HPAIV in eggs than with H5N2 infected hens and the ability of vaccination to protect is unknown. Individually housed sham-vaccinated, inactivated H5N1 Once or Twice vaccinated adult White leghorn hens were challenged intranasally 2-weeks post-vaccination with clade 22.214.171.124 H5N1 HPAIV (A/chicken/Vietnam/NCVD-675/2011) (VN/11). The sham-vaccinated hens experienced 83% mortality within 3 days post-challenge (dpc), and major changes in reproductive parameters including drops in egg production and laying of soft and thin-shelled eggs. All Once and Twice vaccinated layers survived infection, although some Once vaccinated birds experienced thin-shelled egg production. Seroconversion of surviving birds was assessed, the presence and quantity of virus located on (egg shell) or within (albumin and yolk) eggs was determined, and histopathologic changes due to virus replication in the reproductive tract were examined in order to define the effect of once or twice vaccination as a mitigation strategy.