Canine Distemper in Wild Raccoons (Procyon lotor) at the Metropolitan Toronto Zoo

An outbreak of canine distemper, involving at least 23 wild raccoons, occurred at the Metropolitan Toronto Zoo between May and August 1981. Wild red foxes were not found with distemper and the disease did not occur in the captive collection. The main clinical signs were lethargy, bilateral purulent ocular discharge, dehydration and emaciation. The main pathological findings were generalized lymphadenopathy, splenomegaly, and interstitial pneumonia. Heavy infestations with intestinal nematodes (Baylisascaris procyonis), and unidentified cestodes were found. Cryptosporidia were found on the epithelium of the duodenum in 42% of the animals examined. Eosinophilic intracytoplasmic and intranuclear inclusions were numerous in the epithelium of the urinary bladder, renal pelvis, stomach and lung. This local outbreak was part of a major eruption of the disease in raccoons in southern Ontario which began in early 1981 and persisted until the submission of this paper in mid 1983.