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Title: Vaccine protection of turkeys against H5N1 highly pathogenic avian influenza virus with a recombinant HVT expressing the hemagglutinin gene of avian influenza

item Kapczynski, Darrell
item DORSEY, KRISTI MOORE - Biomune Company
item CHRZASTEK, KLAUDIA - Orise Fellow
item MORAES, MAURO - Biomune Company
item JACKWOOD, MARK - University Of Georgia
item HILT, DEBRA - University Of Georgia
item GARDIN, YANNICK - Biomune Company

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2015
Publication Date: 1/15/2016
Publication URL:
Citation: Kapczynski, D.R., Dorsey, K., Chrzastek, K., Moraes, M., Jackwood, M., Hilt, D., Gardin, Y. 2016. Vaccine protection of turkeys against H5N1 highly pathogenic avian influenza virus with a recombinant HVT expressing the hemagglutinin gene of avian influenza. Avian Diseases. 60(2):413-417. doi: 10.1637/11267-090115-Reg.

Interpretive Summary: Avian influenza (AI) viruses cause widespread morbidity and mortality in domestic and wild bird populations and threaten the U.S. poultry food supply and safety. Highly pathogenic (HP) AI is an economically important disease of poultry that has significant impact on global trade. Vaccination against HPAI virus is one of the possible options available for affected countries to control HPAI when the disease is present. In these studies, we examine the protection induced by a recombinant vaccine against HPAI in turkeys. The results demonstrate that vaccine provided high levels of protection against lethal H5N1 HPAI virus challenge. These studies further our knowledge of the requirements of vaccine formulation during HPAI outbreaks.

Technical Abstract: Outbreaks of H5 highly pathogenic avian influenza (HPAI) in commercial poultry are a constant threat to animal health and food supplies. While vaccination can enhance protection and reduce the spread of disease, there is considerable evidence that the level of immunity required for protection varies by subtype and virulence of field virus. In this study, the efficacy of a recombinant turkey herpesvirus (rHVT) vector vaccine expressing the hemagglutinin gene from a clade 2.2 AI virus (A/Swan/Hungary/4999/2006) was evaluated in turkeys for protection against challenge with A/Whooper Swan/Mongolia/L244/2005 H5N1 HPAI clade 2.2. One-day-old turkeys received a single vaccination and were challenged at 4 wk postvaccination with 2 3 106 50% embryo infectious dose per bird. The results demonstrate that following H5N1 HPAI challenge 96% protection was observed in rHVT-AI vaccinated turkeys. The oral and cloacal swabs taken from challenged birds demonstrated that vaccinated birds had lower incidence and titers of viral shedding compared with sham-vaccinated birds. From respiratory and astrointestinal tracts, there was a greater than 6 log10 reduction in shedding in vaccinated birds as compared with the controls. This study provides support for the use of a commercially available rHVT-AI vaccine to protect turkeys against H5N1 HPAI.