|BERTRAN, KATERI - Non ARS Employee|
Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2015
Publication Date: 3/10/2015
Publication URL: http://handle.nal.usda.gov/10113/60565
Citation: Bertran, K., Moresco, K.A., Swayne, D.E. 2015. Impact of vaccination on infection with Vietnam H5N1 high pathogenicity avian influenza virus in hens and the eggs they lay. Vaccine. 33(11):1324-1330.
Interpretive Summary: High pathogenicity avian influenza virus (HPAIV) infections in chickens negatively impact egg production and cause egg contamination. Sham, inactivated H5N1 Once (1X-Vax) or Twice (2X-Vax) vaccinated adult hens were challenged with Asian H5N1 HPAIV (A/chicken/Vietnam/NCVD-675/2011). Sham-vaccinated layers experienced 83% mortality within 3 days post-challenge and laid soft and thin-shelled eggs. Virus was recovered from oral swabs and in 45% of the eggs from eggshell surface (27%), yolk (18%), and albumin (36%). Very high titers of virus were recovered from all segments of the oviduct and ovary, and histopathological changes indicative of HPAIV infection were observed in all sections of the reproductive tract. On the contrary, 1X- and 2X-Vax challenged hens survived infection, continued laying eggs throughout the observation period, and had significantly lower number of contaminated eggs and virus quantity in them as compared to sham-vaccinated hens. Double immunization provided optimal serological protection against HPAIV compared to single immunization. The current study demonstrated that AIV infections caused by Asian H5N1 variants can be effectively controlled by either double or single homologous vaccination.
Technical Abstract: High pathogenicity avian influenza virus (HPAIV) infections in chickens decrease egg production and eggs that are laid contain HPAIV. Vaccination once or twice was examined as a way to protect chickens from Vietnamese H5N1 HPAIV. Eighty-three percent of hens without vaccination died within 3 days after HPAIV challenge; laid soft and thin-shelled eggs; and virus was recovered from eggshell, inside eggs, and from the oviduct and ovary. By comparison, vaccinated hens survived, continued laying eggs, and had fewer HPAIV contaminated eggs and such eggs had less virus. The current study demonstrated that H5N1 HPAIV infections can be effectively controlled by either single or double vaccination.