Comparative Study of Vaccine-Induced Humoral Immune Response Against Newcastle Disease Virus and Avian Influenza Virus (H9N2) in Different Bird Species of Mashhad Birds Garden.

Viral diseases are the primary cause of disease and economic loss in all bird species. Among viral diseases, Newcastle disease (ND) and avian influenza (AI) have a very special place due to their high morbidity and high mortality. They inflict lots of deaths and economic losses upon poultry and nonpoultry avian species, making them a hot subject in various research. Thus, prevention measures and strategies to control the mentioned diseases are wide. Vaccination is one of the common methods. In this study, we designed a vaccination protocol based on previous and popular methods to evaluate the effect of ND and AI vaccines on the humoral immune response of 14 bird species. We tested 115 birds (sampled twice) with no previous encounter with disease or vaccine. Birds were vaccinated with NDV B1 strain and a bivalent inactivated ND + AI and repeated 5 weeks later. Haemagglutination Inhibition (HI) was used for humoral response evaluation and implemented 5 weeks after each vaccination. Our results showed a double vaccination of ND can boost the immune system significantly, but a single AI vaccination will provide enough protection since the second vaccination did not change the titres significantly, even lowering the titre in one case. There were some discrepancies in results, which further studies should be accomplished to elaborate the details.