Cow mortality is not a frequently reported result of WD outbreaks, and the economic losses are more often related to drops in milk production. In this case, three animals died as a consequence of the disease severity, but WD-induced mortality has previously been described, even with the addition of supportive therapy (Natsuaki et al., 2007). Genetic adaptation of the winter-circulating BCoV strains has also been reported (Park et al., 2006). The presence of strains that are more pathogenic could also be a determinant of disease morbidity and mortality.