H9N2 AI and NDV shedding pattern in SPF and commercial layer vaccinated chicken with trivalent vaccine containing H9N2 AI, LaSota, classical M41 and var 2 IB viruses challenged at 1, 3 and 7 months post vaccinationHanan Sayed, Mohamed Sayed Madkour, Hussein Ali Hussein, Mounir Mohamed Elsafty, Marwa F El saied, Ahmed A El-Sanousi.
Background: Prolonged immune protection for H9N2 and Newcastle in layer chicken rearing is an important issue.
Objective: To evaluate the protection duration for H9N2 and NDV post vaccination by inactivated trivalent (H9N2, LaSota, M41 and Var2 IB) vaccine based mainly on repetition of challenge. Methods: We prepared formalin inactivated combined vaccine for Avian Influenza (H9N2N), Newcastle (La), and IB (M41 and Var 2) by using montanide 71 adjuvant. The prepared vaccine was injected intramuscularly in specific pathogen free and commercial layer chicken, the injection was repeated as a booster vaccination one month after the first vaccination. Humoral immune response was measured by HI for both H9N2 and LaSota viruses weekly for one and a half month after the booster vaccination, then monthly until the end of duration. Challenge trials were carried out after a month from the first vaccination, and after two and six months from the booster vaccination.
Results: Usage of formalin inactivated combined H9N2, LaSota and IB (M41 and Var 2) vaccine with montanide 71 adjuvant decreases the shedding pattern of H9N2 and NDV in SPF and commercial layer chicken for six months after the booster vaccination.
Conclusion: Formalin inactivated, montanide 71 adjuvanted combined H9N2, LaSota and IB (M41 and Var 2) vaccine induces protection for 7 months against challenge with Avian Influenza (H9N2) and Newcastle viruses when vaccination repeated after one month from the first vaccination.
H9N2; Newcastle; SPF chicken; layer chicken.