Canine Distemper

puppies Canine distemper is a highly contagious and serious disease caused by a virus that attacks the respiratory, gastrointestinal, and nervous systems of puppies and dogs. It is usually spread by the secretions from an infected animal’s cough or sneeze. The virus also infects wild canids (e.g. foxes, wolves, coyotes), raccoons, skunks, and ferrets, and these animals can be sources of infection for pet dogs.

Signs of distemper

Although the first sign of distemper is usually eye discharge that may appear watery to pus-like, a dog with a “weepy eye” doesn’t necessarily have distemper. Infected dogs then develop fever, nasal discharge, coughing, lethargy, reduced appetite, vomiting, and diarrhea. In later stages, the virus may attack the nervous system, causing seizures, twitching, or partial or complete paralysis. Occasionally, the virus may cause footpads to harden.

Distemper is often fatal. Even if a dog does not die from the disease, canine distemper virus can cause irreparable damage to a dog’s nervous system.


No specific drug is available that will kill the virus in infected dogs. Treatment consists primarily of efforts to prevent secondary infections; control symptoms; and combat dehydration through administration of fluids. Ill dogs should be kept warm, receive good nursing care, and be separated from other dogs.

Preventing distemper

All dogs are at risk but puppies younger than four months old and dogs that have not been vaccinated against canine distemper are at increased risk. Key elements of canine distemper prevention are vaccination and avoiding contact with infected animals. Until a puppy has received its complete series of vaccinations, pet owners should use caution when taking their pet to places where young puppies and dogs of unknown vaccination history congregate (e.g. pet shops, parks, puppy classes, obedience classes, doggy daycare, and grooming establishments). Pet owners should be sure that their dog’s distemper vaccination is up-to-date. Ask your veterinarian about a recommended vaccination program for your dog. Contact with known infected dogs should always be avoided. Similarly, contact with raccoons, foxes, skunks, and other potentially infected wildlife should be discouraged.

The content on this page is a condensed version of our brochure, Canine Distemper, available in English and Spanish.