IMMUNOSUPPRESSION AS A FACTOR IN ALLOWING MUCOSAL DISEASE TO OCCUR

In order to verify the role of immunosuppression in the pathogenesis o f Bovine Viral Diarrhea Virus (BVDV) infection, two experiments have b een carried out. In one experiment, calves previously infected with cy topathogenic (CP) or non-cytopathogenic (NCP) BVDV were treated with d examethasone (DMS) 30 days later. In the other experiment, calves were simultaneously exposed to BVDV infection and to DMS treatment. In bot h experiments the DMS treated calves developed a more serious disease which in one calf was fatal. It was speculated that immunosuppression represents one of the most significant ''key factors'' in the occurren ce of the bovine viral diarrhea/mucosal disease in cattle.