INFECTIOUS BURSAL DISEASE AND HEMORRHAGIC ENTERITIS

Infectious bursal disease (IBD) of chickens and hemorrhagic enteritis (HE) of turkeys are caused by infectious bursal disease virus (IBDV) a nd hemorrhagic enteritis virus (HEV), respectively. Both diseases have common features, including an acute stage followed by immunosuppressi on, resulting in lowered resistance to a variety of infectious agents and poor response to commonly used vaccines. The IBDV and HEV infectio ns are widespread in commercial chicken and turkey flocks, respectivel y. The acute stage of the disease, the immunosuppression that follows, and the widespread distribution of both diseases, are major factors c ontributing to the economic significance of both diseases. The mechani sm of immunosuppression for both infections has similarities, both aff ect lymphocytes and macrophages, and both are lymphocidal. In this rep ort, an overview of both diseases with emphasis on some of the recent findings will be presented. There has been greater research activity o n IBD than on HE, reflecting the relative economic importance of the s pecies affected and the recent changes in the antigenic make up and pa thogenicity of the IBDV.