Etiologic Studies of Old Dog Encephalitis

Abstract

In 2 cases of old dog encephalitis (ODE), viral antigen to canine distemper was demonstrated in frozen brain tissue by means of the direct FA test. The distemper viral antigen was most abundant in cells of the gray matter of the cerebral cortex, thalamus, mesencephalon, and medulla. Also, in the 1 dog in which serum was available, there was a significantly elevated serum antibody titer to the distemper agent. Attempts to isolate a viral agent in tissue culture or to transmit disease to distemper-susceptible ferrets or distemper-immune adult dogs were unsuccessful. Results of this study indicate that the virus of distemper play a role in the pathogenesis of ODE. Also, the progressive disease with inflammatory reaction suggests that a slow viral infection rather than a totally masked or latent virus be involved.