Effectiveness of different avian influenza (H5) vaccination regimens in layer chickens on the humoral immune response and interferon-alpha signalling immune marker

AbstractAvian influenza (AI) vaccines are widely used to control and eliminate the ongoing avian influenza virus epidemic in Egypt. A strict vaccination policy with inactivated AI vaccines has been widely applied, however the virus still circulating, evolving and causing great negative impact to the poultry sector in Egypt. Therefore, an updated poultry vaccination policy using different vaccine technologies might be valuable as an innovative additional control strategy of AIV in Egypt. In the present study, the effectiveness of different avian influenza (AI) vaccination schedules was evaluated in 300 commercial layer chicks (ISA White) using either the oil-emulsion baculovirus-H5-prototype vaccine (baculovirus-H5 prototype) or turkey herpesvirus (HVT) vector vaccine containing the hemagglutinin (HA) gene from H5N1 strain (rHVT-H5), applied alone or in combination and in different settings. Vaccination with either two injections of the baculovirus-H5 prototype, a single injection of rHVT-H5 or priming with rHVT-H5 at 1  day old followed by boosting with the baculovirus-H5 prototype induced AI-HI protective antibody responses starting as early as 3 to 4 weeks of age and lasting up to the end of the rearing period (16 weeks). A single vaccination with the baculovirus-H5 prototype did not generate a protective ant ibody titre for the entire rearing period. Furthermore, the present study elucidated that vaccination once or twice with the baculovirus-H5 vaccine prototype activa...
Source: Veterinary Research Communications - Category: Veterinary Research Source Type: research