Dual infection with an emergent strain of canine distemper virus and canine parvovirus in an Arctic wolf under managed care

A 6-wk-old managed male Arctic wolf with lethargy, drooling, dehydration, elevated temperature, and acute onset of seizures was submitted for autopsy. The wolf had been vaccinated with a multivalent vaccine exactly 2 wk prior to presentation. Grossly, long bones were brittle and easily fractured under pressure; the intestinal contents were mucoid and yellow. Histologically, there was widespread lymphoid and hematopoietic necrosis, failure of endochondral ossification within long bones, as well as intranuclear and intracytoplasmic inclusions in various tissues and cell types. Canine distemper virus was detected in numerous tissues by IHC and confirmed by RT-rtPCR and sequencing as an American-4 strain, an emerging strain in domestic dogs and wildlife species in the southeastern United States. The clinical and pathologic findings associated with this emergent CDV strain have not been reported previously in wolves, to our knowledge. Canine parvovirus 2 (CPV-2b) was also detected in the spleen by IHC and confirmed by conventional PCR as a wild-type strain. The exact impact of CPV-2b on the clinical course is unknown. Early vaccination in this case may have predisposed this Artic wolf to developing clinical disease.