Bovine Winter Dysentery Study Guide

Overview and Clinical Importance

Winter dysentery (WD) is an acute, highly contagious gastrointestinal disorder that primarily affects housed adult dairy cattle during winter months. The disease is caused by bovine coronavirus (BCoV), an enveloped, positive-sense, single-stranded RNA virus belonging to the genus Betacoronavirus, species Betacoronavirus 1.

Winter dysentery represents one of three clinical syndromes associated with BCoV infection in cattle, the others being neonatal calf diarrhea and respiratory disease (shipping fever) in feedlot cattle. The disease is characterized by high morbidity (50-100%) but low mortality (1-2%), with the primary economic impact being a profound and often prolonged decrease in milk production.

Etiology

Causative Agent: Bovine Coronavirus (BCoV)

Bovine coronavirus is an enveloped, pleomorphic virus with a diameter of 65-210 nm. The virus possesses a positive-sense, single-stranded RNA genome and belongs to the family Coronaviridae. BCoV has 95% genetic similarity with human coronavirus OC43 (causes common cold) and 93% similarity to porcine hemagglutinating encephalomyelitis virus.