Recovery from and Clearance of Rabies Virus in a Domestic Ferret

Here we document the case of a domestic ferret (Mustela putorius) that survived experimental inoculation with rabies virus of skunk origin. The ferret showed initial clinical signs of rabies (hindlimb paralysis) on day 81 after inoculation. The animal survived with paraplegia but otherwise was in an adequate nutritional state until the end of the observation period (PI day 181). At necropsy, no gross lesions were observed. Microscopic lesions were found in sections of cerebrum and spinal cord. In both tissues, the lesions were similar but were more severe with loss of neuronal parenchyma in the spinal cord. The lesions consisted of locally extensive areas with proliferation of astrocytes and moderate numbers of glial cells. Severely affected areas also contained clearly defined vacuoles in the neuropil. Multifocal areas of involvement showed mononuclear cuffing of blood vessels. In a few areas, the cuffing extended to the meninges. Rabies virus antigen was not detected by immunohistochemistry of tissue sections.