Viral excretion in domestic ferrets (Mustela putorius furo) inoculated with a raccoon rabies isolate

Objective-To determine susceptibility incubation and morbidity periods, cli nical signs of infection, serologic response, and excretion of virus in dom estic ferrets inoculated with rabies virus of raccoon origin. Animals-54 domestic ferrets. Procedure-5 groups of ferrets were inoculated IM with the rabies virus. Ora l cavity swab specimens and saliva were obtained for virus isolation. Blood was obtained for virus-neutralizing antibody determination. If clinical si gns were severe, ferrets were euthanatized immediately. Salivary gland and brain tissue was collected for virus isolation and rabies diagnosis, respec tively. Results-Of 51 inoculated ferrets, 19 (37%) were euthanatized with clinical signs of rabies. Mean incubation period was 28 days (range, 17 to 63 days). Clinical signs included ataxia, cachexia, inactivity, paresis, paraparesis , bladder atony, tremors, hypothermia, lethargy, constipation, paralysis, a nd anorexia. Two rabid ferrets manifested aggressive behavior. Mean morbidi ty period was 4 to 5 days (range, 1 to 8 days). Virus antigen was detected in brain tissue from all rabid ferrets (n = 19). Two rabid ferrets had dete ctable virus-neutralizing antibody. Of 32 ferrets that survived, only 1 ser oconverted; survivors remained clinically normal throughout the observation period. Babies virus was isolated from salivary glands of 12 of 19 (63%) r abid ferrets, and 9 (47%) shed virus in saliva. Initiation of virus excreti on ranged from 2 days before onset of illness to 6 days after onset. Conclusions and Clinical Relevance-Babies should be considered in the diffe rential diagnosis for ferrets that have acute onset of paralysis or behavio ral changes and a condition that rapidly deteriorates despite intense medic al intervention.