Devastating botulism outbreak in cattle, associated with contaminated soil

We describe here cases of botulism at two dairy cattle farms where the soil was submerged by flooding from an adjacent river. All cattle at farms 1 and 2 (91 and 56 head, respectively) died or were euthanized with posterior flaccid paralysis and recumbency. Necropsy and histopathological examination showed no specific lesions. Botulinum toxin type B was detected in sera of the affected cattle, and type D toxin was found in ruminal contents and soil from cattle pens at both farms. A likely source of the botulinum toxin is the soil of the adjacent river, from which toxins were introduced during flooding. To our knowledge, these appear to be the first cases of bovine botulism associated with contaminated pen soil after flooding.