Infectious bur sal disease - a worldwide problem

摘要

Infectious bursal disease (IBD), first recognised in the early 1960s, remains a significant problem in the world's poultry industries. The infection is encountered in all countries, with the exception of New Zealand, in various forms ranging from mildweight loss and low mortality in broilers associated with infection and immunosup-pression, to severe losses following exposure to very virulent strains (vvlBDV) of the virus. Since the virus is resistant to environmental exposure and persists in litter and housing, early exposure of flocks invariably occurs, resulting in the destruction of lymphoblasts in the bursa of Fabricius.