By Mike Sievering, Supervising Wildlife Biologist, Retired

Furbearer populations are susceptible to a variety of viral diseases such as rabies, canine hepatitis and canine distemper. Without a doubt, the latter is the most common and most limiting of the viral diseases. It can be an important mortality factor in wild furbearer populations.

Canine distemper is highly contagious and is fairly common in furbearer populations in the southeast United States. This viral disease is seen in domestic dogs and wild carnivores such as coyotes, foxes, skunks, otters and minks and is particularly noticeable in raccoons. It can appear in any time of the year, but is primarily seen during the fall and winter months.

The spread or transmission of canine distemper occurs through either direct contact or through aerosol contamination. In furbearer populations, there is very little natural immunity to this disease. The occurrence and spread of canine distemper is related mainly to population densities. As population levels increase canine distemper appears to increase. The prognosis is generally poor for distemper-infected animals. Mortality rates can range from 50 percent in raccoon populations to as high as 90 percent in mink. There is no known cure for canine distemper. Infected animals show a variety of symptoms with this disease. They exhibit behaviors ranging from lethargy to aggression.

Commonly exhibited symptoms are as follows: swollen eyelids, milky white discharge from eyes, runny nose, emaciated looking, unkept appearance to fur, diarrhea, a cough in some cases, terminal convulsions, progressive blindness and infected animals display a total lack of fear towards humans. In addition, infected animals seem to wander aimlessly in the middle of the day. These animals are easily approached and put up little resistance when captured. The latter stages of canine distemper are somewhat difficult to witness. Infected animals such as raccoons will have epileptic seizures. During these seizures, the animal’s jaws will snap convulsively and their hind legs will become rigid. After the seizures, these animals will go into a deep sleep.

Canine distemper is not a threat to humans; however, domestic pets and furbearer populations are susceptible to this disease. This disease can be considered one of the most limiting factors to furbearer populations. In order to minimize the spread of this disease in furbearer populations it will be necessary to keep population levels low. This can be accomplished by utilizing these particular species as a fur resource