The disease is highly infectious, and outbreaks in households must be carefully managed to prevent high mortality rates. The symptoms of this disease are quite distinct in the terminal stages, but initially they resemble an upper respiratory disease like influenza. After exposure to the virus, no signs are evident during the incubation period of 5 to 7 days. Then loss of appetite, lethargy and a thick discharge from the eyes and nose develops. The eyelids may crust shut.
Fever is common in ferrets with distemper.
As the disease progresses, red skin rashes consistently develop on the chin, muzzle and in the inguinal area. The footpads may become thick and dry. Ultimately the virus can infect the nervous system leading to convulsions, coma and death. Diagnosis of canine distemper in live ferrets can be made by special tests such as fluorescent antibody techniques on blood smears and conjunctival scrapings. Diagnosis can be made on autopsy of affected individuals because viral elements called inclusion bodies are found on microscopic examination of many different tissues.