Cerebrospinal Nematodiasis in a woodchuck suspected of having rabies.

A young woodchuck (Marmota monax) with a history of CNS dysfunction and abnormal behavior was submitted frozen to the Animal Disease Diagnostic Laboratory, Purdue University, as a rabies suspect. The woodchuck was negative for rabies by the fluorescent antibody test. Histologically, multifocal areas of necrosis, malacia, and inflammation were seen in sections of cerebrum, midbrain, and cerebellum, accompanied by marked perivascular cuffing with eosinophils and lymphocytes. Sections of lung contained parasitic granulomas, one of which contained a large ascarid larva identified as Baylisascaris sp. The CNS lesions were typical of parasite migration, and resembled those commonly associated with infection with Baylisascaris larvae of raccoon or skunk origin. Cerebrospinal nematodiasis was diagnosed as the cause of the nervous disorder.