Coenurosis of sheep in southern Brazil: 16 Cases

Abstract

Sixteen cases of neurologic disease caused by Coenurus cerebralis occurring in sheep from nine farms in Rio Grande do Sul, Brazil, from January 1990 to December 2006, are described. Clinical courses varied from 30 to 90 days and affected sheep developed depression (9/16), isolation from the herd (8/16), staggering (7/16), blindness (4/16), head tilt (3/16), incoordination (3/16), paddling (2/16), falls (2/16), circling, proprioceptive deficits in fore and hindlimbs, strabismus, mydriasis, opisthotonus, trembling and rigidity of the limbs (1/16 each one). Macroscopic findings were restricted to central nervous system and consisted of 2 to 9cm fluid filled cysts with numerous slightly elongated 1 mm white scolices attached to the inner wall surface of the capsule. Cysts were located in the telencephalon (12/16); in the cerebellum (3 sheep); and in the cerebellum and spinal cord (1 sheep). All cases showed severe compression and displacement of the adjacent nervous tissue. Histologically, the cyst walls were characterized by a thin walled eosinophilic vesicle in which evaginated multiple spherical acelomated scolices. The cyst wall was surrounded by successive layers consisting of an internal necrotic and mineralized band, a layer of epithelioid macrophages with abundant number of multinucleated giant cell and an external fibrovascular capsule with perivascular lymphohistioplasmacytic infiltrate. Adjacent white and gray matter were compressed and atrophied. The diagnosis was based on epidemiologic, clinical and pathologic findings and confirmed by histopathology.