Serologic evaluation, efficacy, and safety of a commercial modified-live canine distemper vaccine in domestic ferrets

Objective-To determine efficacy and safety of a commercial modified-live ca nine distemper virus (CDV) vaccine used far prophylaxis in domestic ferrets . Animals-Sixteen 16-week-old neutered male ferrets. Procedures-Equal groups of ferrets were inoculated subcutaneously at 16 and 20 weeks of age with saline (0.9% NaCl) solution or a vaccine derived from the Onderstepoort CDV strain and attenuated in a primate cell line. Live v irulent CDV was administered to all ferrets intranasally and orally 3 weeks after the second inoculation. Clinical signs and body weights were monitor ed regularly during the study. Blood samples for serologic examination Were drawn prior to each inoculation, before challenge exposure, and 10, 15, an d 21 days after exposure. Blood samples for reverse transcriptase polymeras e chain reaction (RT-PCR) were obtained 5 days after the first vaccination, and 5, 10, 15, and 21 days after challenge exposure. Results-After challenge exposure, control ferrets had significantly more cl inical signs and weight loss, compared with vaccinates. Ail vaccinated ferr ets survived, whereas all control ferrets died. The RT-PCR fresh or formali n-fixed tissues from infected ferrets. Conclusions and Clinical Relevance-Findings suggest that the vaccine when g iven SC to domestic ferrets as directed is safe and protective against chal lenge exposure with virulent CDV. The RT-PCR assay may simplify detection o f CDV in fresh and fixed tissues.