Protective efficacy of commercial live vaccines against very virulent infectious Bursal disease virus (vvIBDV) in Ghana

Abstract

In spite of the intensive and varied vaccination procedures to control Infectious Bursa Disease (IBD), the emergence of a very virulent (vv) IBD pathotype in Ghana has led to high economic losses in the poultry industry. The potencies of two live intermediate IBD vaccine strains (TAD and Nobilis D78) and an intermediate-plus (hot) vaccine strain (228E) used in Ghana were evaluated by challenging Specific Antibody Negative (SAN) chicks with a vvIBD virus (LV/G19) which was recently isolated in Ghana. Serum samples were obtained from all chicks before vaccination and virus challenge. Antibody titres were measured by Enzyme-linked Immunosorbent assay (ELISA). Body weight, bursal weight and bursa to body weight measurements were also taken. All vaccinated chicks were fully protected from the vvIBD virus, as neither morbidity nor mortality was observed in the vaccinated chicks after challenge. The intermediate–plus (hot) IBD vaccine elicited the highest antibody titers but caused reduction in the size of the bursa of Fabricius. Taken together, the results of this study showed that vaccines currently in use in Ghana can protect chicken against the locally-isolated vvIBD virus. Key words: Infectious bursal disease, vaccine efficacy, intermediate, intermediate-plus (hot).