ABSTRACT: This study described the epidemiological and clinical-pathological aspects of 25 outbreaks of neurological diseases in cattle caused by plants and mycotoxins in Santa Catarina state. Six of them were due to Sida carpinifolia poisoning, five to Solanum fastigiatum, five to Phalaris angusta, three to Claviceps paspali, three to Claviceps purpurea, and three outbreaks were of unknown etiology. The clinical signs observed in the affected cattle were mild to severe and characterized by generalized muscle tremors, incoordination, hypermetria, wide-based stance, intentional head tremors, dull staring eyes, and frequent ear twitching, with convulsions in some cases. At necropsy, lesions were observed only for P. angusta poisoning, characterized by gray-greenish discoloration in thalamus and midbrain. Microscopically, rarefaction and/or disappearance of Purkinje neurons with substitution by Bergmann cells were observed for S. carpinifolia and S. fastigiatum poisoning. For P. angusta poisoning, thin granular brown-yellowish pigment was observed in the cytoplasm of some neurons. Gross and microscopic findings were not observed in three outbreaks of tremorgenic disease of unknown etiology. Experiments conducted with leaves, flowers and seeds of Ipomoea indivisa and Ipomoea triloba, as well as with maize and soybean residues contaminated with Ipomoea spp. did not reproduced clinical signs.
Neurological diseases of unknown etiology: Brain-biopsy diagnostic yields and safety
