DISTEMPER IN WILD CARNIVORES - AN EPIDEMIOLOGIC, HISTOLOGICAL AND IMMUNOCYTOCHEMICAL STUDY

Brain tissue from 236 wild carnivores, 146 mustelids and 90 foxes, ori ginating from the same geographical area in southwest Germany was coll ected over a 2 year period between May 1989 and May 1991 and studied f or the presence of canine distemper virus (CDV) antigen by immunohisto chemistry. CDV antigen was found in the brains of 54 (37%) mustelids, predominantly in the cerebellar grey matter. Interestingly, no CDV inf ection was observed in foxes. An increasing number of CDV infections a mong mustelids was noted between November 1989 and November 1990, peak ing in summer 1990. Histological brain lesions, demonstrated only in 4 5% of the CDV positive mustelids, were characterized by non-purulent e ncephalitis predominantly in the cerebrum and focal vacuolation of the cerebellar white matter, whereas demyelination was only rarely observ ed. Histological and immunocytochemical CNS findings indicate an early stage of distemper infection in these mustelids and the high percenta ge of CDV positive animals together with the seasonal prevalence are s uggestive of a CDV epizootic among mustelids.