Evaluation for Efficacy of Commercially Available Vaccines Against Challenge with Newcastle Disease Virus Genotype VII in Broilers

Abstract

The study evaluated the protective efficacy of commercially available live and inactivated Newcastle Disease Virus (NDV) vaccines. Moreover, study also highlighted the implementation of genotypically-matched NDV vaccines to the currently circulated velogenic genotype VII strain in commercial broilers vaccination regimes in Egypt. Serum antibodies level was assessed by Haemagglutination Inhibition method .Efficacy of Newcastle Disease killed and live vaccine was also determined using challenge test. Group A immunized with live attenuated and inactivated NDV vaccines genotype VII homologous to challenge virus provided non-significant protection against mortality .It proved 20 % as compared to 15 % mortalities in group B immunized with live attenuated and inactivated NDV vaccines genotype II heterologous to challenge virus. Meanwhile, group Aredult proved a significant reduction in viral shedding by cloacal swabs in compared with group B ,7 days post-challenge. Final Results of the present work concluded that live and inactivated NDV genotype VII vaccines antigenically matched to currently epidemic NDV genotype VII providing better control on virus shedding if compared with different genotype II vaccines. However, both vaccines provided good protection against likely virulent challenge in commercial broilers.