Infectious bursal disease (IBD) is a highly contagious disease in young chickens which can result in high morbidity and mortality and also in great economic losses. The main target for the virus is the lymphoid tissue with a special predilection for the bursa of Fabricius. Several
vaccines are available to control the disease. Intermediate plus
vaccines are used in chickens with high maternal antibody titers which face high
infection pressure. An example of an intermediate plus
vaccine is a live
vaccine based on IBD strain V877. The results of an efficacy study in commercial broilers with different levels of maternally derived
antibodies (MDA) showed that the V877-based IBD
vaccine can break through maternal antibody titers of higher than 1100 as determined by an IBD ELISA. The safety of the
vaccine was demonstrated in a study in which specific-pathogen-free (SPF) chickens were vaccinated with a tenfold dose of the
vaccine strain and a tenfold dose of the
vaccine strain after five back passages in SPF chickens. The
vaccine virus caused lesions, as could be expected for an intermediate plus
vaccine, but the scores were not much higher than the maximal scores allowed for mild IBD
vaccines in the European Pharmacopoeia, and reversion to virulence was absent. In studies in SPF chickens, there were no negative impacts by the IBD V877
vaccine on the efficacy of a live QX-like IB
vaccine and a live
Newcastle disease La Sota vaccine in vaccination challenge studies, although the IBD
vaccine had a negative effect on the antibody response generated by the QX-like IB
vaccine. It is concluded that the IBD V877
vaccine has the capacity to break through high levels of MDA, has a satisfactory safety profile, and interactions with other live
vaccines are limited. In order to limit bursal lesions after vaccination it is recommended to confirm the presence of MDA before vaccinating with the V877
vaccine.