Abstract Title
Immunization with HVT-H9 increased survival rate and production efficiency of broilers in the field after natural infection of H9N2 avian influenza virus
Abstract
H9N2 avian influenza virus (AIV) was prevalent worldwide. The prevention and control of H9N2 AIV in China could provide insight for that globally. Long-term application of H9N2 inactivated vaccines has been conducted in China. Although the inactivated vaccine alleviated clinical symptoms as challenging with H9N2 AIV, it could not block virus infection and transmission in the field, thus leading to the sustained circulation of H9N2 AIV and causing huge economic losses and even human infection. Turkey herpesvirus (HVT) vector vaccine expressing hemagglutinin from H9N2 AIV, namely HVT-H9, were demonstrated to block H9N2 AIV infection in chickens in laboratory studies. In further, immunoprotect effect of HVT-H9 was evaluated in the field. The mortality rate of broilers immunized with HVT-H9 was significantly reduced compared to that immunized with inactivated vaccine under natural infection with H9N2 AIV. Importantly, repeated experimental results were obtained to confirm that HVT-H9 immunization might block viral infection and improve the survival rate of flocks. The protection efficiency and production performance of broilers were also evaluated in the presence or absence of H9N2 AIV infection. HI titers against H9N2 AIV in broilers were successfully induced by HVT-H9 despite of maternal antibodies. What’s more, HVT-H9 vaccination significantly reduced mortality rates and increased production efficiency in the presence of H9N2 AIV natural infection. In summary, HVT-H9 immunization might block H9N2 AIV infection and improve production efficiency in the field.
Co-Author(s)
Liu Litao, Tong Qi, Sun Honglei, Sun Yipeng, Pu Juan, Liu Jinhua.
Abstract Category
Diagnostics, vaccination, or other mitigation strategies for poultry and wildlife