Abstract

The current study was conducted to evaluate the pathogenicity and pathology of infectious bursal disease virus in commercial chickens. A total of 45 broiler bursa were collected from 9 commercial flocks of different age (18-29 days) of different areas at sylhet region. During necropsy chickens and Bursa of Fabricius (BF) were weighed and examined for any gross lesion and processed for histological investigations. Bursa body weight ratio and bursal lesion scoring were made to evaluate pathogenicity of the virus. The results shows that the weight of bursa increased effectively according to the body weight. According to the evaluation system bursa were scored as excellent, average, medium and bad. In post mortem examination there was severe hemorrhage present on BF, breast, thigh muscle and also at the junction between proventriculus and gizzard. Gelatinous and atrophied bursa was found. Bursalleison score were done based on histopathological investigations and highest bursalleison score was 4.6±0.40. Bursa were characterized by atrophy, necrosis, fibroplasia, lymphoid depletion, cyst formation and infiltration of inflammatory cells. In conclusion, the bursa characteristics bursal index/bursa-body weight ratio, gross lesion and bursalleison scoring are practical for any field investigations to evaluate the pathogenicity of Infectious Bursal Diseases virus (IBDV).

Keywords

bursa-body weight ratio, pathology and bursalleison scoring, atrophy, bursal