An outbreak of besnoitiosis in miniature donkeys.

Fourteen miniature donkeys (Equus asinus) in a mid-Michigan herd of 38 animals presented with clinical signs of besnoitiosis, including the presence of typical tissue cysts in the ocular sclera, the buccal and nasal mucosa, together with characteristic dermatitis in specific areas of the body. The common histopathological change seen was the presence of many 100-200-microm diameter, thick walled, typical Besnoitia sp. tissue cysts together with a chronic cellular response associated with degenerating cysts.