Outbreaks of Infectious Bursal Disease in Vaccinated and Unvaccinated Commercial Cockerel Farms in Bangladesh

Abstract

Infectious bursal disease (IBD) is a contagious viral disease has been reported in young broiler and layer chickens from Bangladesh. This communication report the outbreaks of IBD on two vaccinated (Gumboro D78®, Intervet) and one unvaccinated commercial cockerel farms which were diagnosed on clinico-pathological findings and assessment of ELISA antibody titre. The outbreaks of IBD occurred on two vaccinated farms in cockerels of 29 to 31 days (Farm 1) and 30 to 33 days (Farm 2), whereas 19 to 22 days old in unvaccinated (Farm 3) birds. It caused 39.38% (Farm 1) and 75.0% (Farm 2) mortality in vaccinated and 29.20% (Farm 3) in unvaccinated cockerel farms. Clinical investigation showed rapid onset, dullness, depression, anorexia, whitish loose diarrhoea, soiling and pasting of the vent, ruffled feathers, trembling and finally prostration and death due to dehydration. Necropsy examination revealed dehydrated carcasses, enlargement and oedematous swelling of bursa Fabricius and some cases yellowish, haemorrhagic, yellowish and caseous exudate in the bursa. Skeletal muscles especially thigh muscles showed haemorrhages in some birds. The IBD ELISA antibody titre of both the vaccinated and the unvaccinated moribund cockerels showed at vulnerable state and the mean antibody titre of vaccinated farm 1 had 161 ± 59.22 and vaccinated farm 2 had 57.82 ± 14.85, whereas unvaccinated farms had 194 ± 90.35. The occurrence of IBD outbreaks in both the vaccinated and unvaccinated birds indicate not only vaccination failure but also defective control strategies, which resulted heavy economic loss (85.05%) in the three cockerel farms. Therefore, a sound control strategy requires monitoring of maternal derived antibody with correct vaccination policy as well as good biosecurity principles to control IBD in Bangladesh.Key words: Outbreaks, infectious bursal disease, cockerels, vaccination failure DOI = 10.3329/bjvm.v1i1.1912 Bangl. J. Vet. Med. (2003). 1 (1) : 21 - 24 Â