Nervous signs in bovine coccidiosis

In 2 outbreaks of coccidiosis due to E bovis and/or E zurnii infection in Canadian cattle, nervous signs included opisthotonos, medial strabismus, hypersensitivity, tetanic spasms, and convulsions. All of the affected animals died in convulsions after an illness of one to several days during which time they showed periodic nervous signs. Necropsy revealed a very severe enteritis with the most severe lesions in the spiral colon. Much of the intestinal mucosa in this area had been destroyed by the parasite. None of several suggested causes of such nervous signs was indicated by laboratory findings, but the possibility of toxins produced by the coccidia could not be ruled out.