Canine distemper in a Raccoon

A raccoon was observed stumbling and foaming at the mouth in a public area of F.E. Warren Airforce Base. The immediate public health concern was possible rabies virus infection and risk of human exposure. Other public health concerns included possible toxin or poison exposure. Rabies testing at the Wyoming State Veterinary Laboratory was negative. Due to the close contact with humans, a definitive diagnosis was pursued in the case. Canine distemper in raccoons and coyotes can mimic the signs of rabies. Canine distemper virus (CDV) is contagious to nonvaccinated dogs and many wild carnivores, but is not contagious to humans. Raccoons with distemper may approach people, appear sick and sleepy, stumble, and have seizures.

Canine distemper virus (CDV) is highly infectious to dogs and other wild carnivores, including big cats such as lions and tigers, but unlike rabies it is not contagious to humans. In Wyoming, CDV has been found in raccoons, coyotes, wolves and unvaccinated domestic dogs. Transmission usually occurs through direct contact with body fluid, including urine and feces. In addition to the neurologic signs seen in advanced cases, sick animals may have respiratory signs such as runny eyes and nose and a cough, or gastrointestinal symptoms such as vomiting and diarrhea. The neurologic signs in advanced cases canine distemper mimic those caused by rabies, or animals may exhibit seizures and muscle spasms. Pet dogs can be tested for CDV. The virus can be detected in samples such as urine or blood, or swabs of the conjunctiva (eye). Deceased animals can be tested using tissues including, lung, brain, and urinary bladder. Supportive care may be beneficial in mild cases, but there is little hope of survival in advanced cases with signs of a brain infection.

Safe and effective vaccines are available for domestic dogs. All puppies should be given a series of 2 or 3 doses, followed by an annual or every three booster to maintain full protection. Since CDV infects raccoons and coyotes, it is not uncommon for Wyoming farm and ranch dogs to become infected with and die from CDV.  This case illustrates why vaccines are recommended for ranch dogs that never come to town and are not often around other dogs.

The main public health concern for this case was potential rabies virus infection. It is important not to approach a wild animal that is acting strangely. If there is any potential for human contact the animal should be tested for rabies and public health officials notified. As this case demonstrates, even in the animal does not have rabies, they could have other infectious diseases and should still be handled appropriately.