Histopathological and ultrastructural alterations of neurons and glial cells of infected sheep brain with Coenurus cerebralis

One of the serious nervous diseases of livestock animals is coenurosis which cause high economic losses in the sheep herds. In the present study, the pathological effects of Coenurus cerebralis on neurons and glial cells were studied in a trial to elucidate the pathway of the associated serious nervous manifestations. Brain specimens from 20 coenurosis infected sheep were examined parasitologically, histologically and ultrastructurally. Degeneration and necrosis of the ependymal cells were the most obvious lesions in the examined histological sections, beside the granulomatous encephalitis. In addition, the cresyl violet stained sections demonstrated the depletion and loss of Nissl granules responsible for the neurotransmission. Ultrastructurally, loss of the myelin sheath, edema and degeneration of the interfasicular oligodendroglia were evident. On conclusion, Coenurus cerebralis causing progressive and fatal nervous manifestations not only as a space occupying lesion as previously mentioned but mainly due to their pathological effect on the ependymal and oligodendroglia cells leading to progression of the neurological signs.