Chronic Shedding of Bovine Enteric Coronavirus Antigen-Antibody Complexes by Clinically Normal Cows

Abstract

SUMMARY Using an ELISA for the detection of virus-specific immune complexes, ten cows were found to be shedding bovine enteric coronavirus. The shedding patterns from five of these animals were followed for a period of 12 weeks, and all were found to be chronically shedding virus. Despite the presence of both faecal and serum antibody the infection was not cleared; therefore, the role of cell-mediated immunity (CMI) was investigated by immunosuppressing the chronically shedding cows with dexametha- sone. No major role for CMI in maintaining the chronic infection could be determined, although immunosuppression did result in a temporary reduction in the shedding of virus-specific immune complexes.