Polioencephalomalacia associated with closantel overdosage in a goat

This report describes clinical and pathological findings associated with closantel (a halogenated salicylanilide anthelmintic) overdosage in a 3-year-old goat. The clinical signs included blindness, incoordination, ataxia, depression of the palpebral and pupillary reflexes, and recumbency. No gross lesions were noted in tissue or organs at necropsy, but microscopic lesions were seen in nervous tissue and hepatic cells. Polioencephalomalacia was clearly evident. Bilaterally symmetrical status spongiosus of the white matter of the brain, bilateral laminar necrosis, microcavitations, ischaemic cell change and severe degeneration of the cerebellum were seen in nervous tissue. Fatty change and hydropic degeneration in the liver and hepato-cellular degeneration were observed histologically.