Bovine abortion caused by Bacillus cereus.

Bacillus cereus was identified as an infrequent abortigenic agent in cattle. Necrotizing placentitis with no or sporadic lesions in fetal tissues was seen. Bacillus cereus was isolated in pure culture from fetal tissue and/or placenta. The recent identification of a bovine abortion caused by B cereus, prompted a retrospective survey of the pathology files. Eight of 947 bovine abortions were attributed to B cereus. Bacillus cereus is often mistaken as a contaminant in bovine abortion because of the failure to identify lesions in fetal tissues compatible with bacterial invasion. A necrotizing toxin may be responsible for the placentitis, with expulsion of the fetus before bacterial colonization.