Clinicopathological findings in dogs with distemper encephalomyelitis presented without characteristic signs of the disease

The clinical diagnosis of distemper is difficult in dogs presented with nervous deficits in the absence of extraneural signs and myoclonus. The aim of this study is to verify how the clinicopathological findings may suggest distemper encephalomyelitis in such cases. We prospectively investigated 20 necropsied dogs presented with neurological signs without those characteristic signs of distemper at the time of hospital admission. Eight out of 20 dogs were diagnosed with distemper encephalomyelitis at post mortem by reverse transcription-polymerase chain reaction (RT-PCR) and histological examination. Cerebellar and/or vestibular signs progressing to tetraparesis/plegia were frequent neurological signs. Abnormalities in hematologic findings were non-specific, nevertheless the cerebrospinal fluid evaluation could suggest canine distemper virus (CDV) infection by a lymphocytic pleocytosis. At post mortem chronic CDV encephalomyelitis was predominant. Our clinical results, as well as the predominance of chronic encephalomyelitis, differ from other studies about CDV encephalomyelitis with naturally infected dogs presenting extraneural signs and myoclonus.