Role of the Bursa of Fabricius in the Pathogenicity of Inclusion Body Hepatitis and Infectious Bursal Disease Viruses

Abstract
Chickens were chemically bursectomized with cyclophosphamide at 3 days old, and studies were made of the effects of infection by inclusion body hepatitis virus (IBHV) and infectious bursal disease virus [IBDV]. In another experiment, 3 wk old chickens were infected with IBDV before inoculation with IBHV. Interference with the bursa of Fabricius by cyclophosphamide or by IBDV enhanced the pathogenicity of IBHV. Cyclophosphamide effects on the bursa protected chickens against IBDV.