STUDIES ON INFECTIOUS BURSAL DISEASE IN COMMERCIAL BROILERS

Abstract

Based on field observations suggesting increased incidence of IBD among vaccinated flocks, th:1s\investigation was dedicated to study some epizootiological features of recent IBD outbreaks in commercial broiler flocks located in Alexandria, Bohira and Kafr El-Sheikh governorates during 1991- 1994, and to investigate the pathogenicity of some isolates recovered from these outbreaks.

Results achieved are as follows :

1 - A total of 42 out of 58 suspected outbreaks were confirmed as IBD by antigen detection in bursal homogenates from affected flocks by the agar gel precipitation test (AGPT).

2- Confirmed outbreaks of IBD caused 1 - 8% mortalities in broilers of 18 -

37 days of age regardless of the type of vaccine used or program of vaccination.

3 - Complicating infections were common in such outbreaks and included

CRD, coccidiosis and E.coli infections.

4 - Eight out of the 42 IDDV- infected bursal homogenates were chosen to study their pathogenicity to chicken embryos by 2 serial passages to 3 • week - old broiler chickens.