Evaluation of Experimental Inactivated Infectious Bursal Disease Vaccine Using a Local Very Virulent Pathotype Strain

By emergence of very virulent infectiolls bursal disease virllses (vvIBOVs), ail classical measures were called into question. In this study an inactivated IBO vaccine with bursal and embryo origins using a recent local vvlBOV isolate, 1R499, was prepared. The virus cultivated in both SPF emberyonated eggs and chicks to evaluate the efTects of host system on immunogenicity of the vaccine. The results showed that inoculation of broiler breeder chickens with the inactivated IBO vaccine at 20 weeks of age produced significantly greater levels of antibody in comparison with IBO live vaccine and induced antibody titers with a lower variation than the other. The mean antibody titer raised by bursal origin vaccine was significantly greater than other inactivated vaccine and it persisted throughout this study. Our result show that inactivated vaccine with bursal origin induces high level of antibodies, which is essential for protecting of the birds against the vvIBOV strain. Also il shows that incillding of very virulent strain in inactivated vaccine provides bcttcr protection against lield vvlBOV strains.