About canine distemper

Canine distemper, commonly called distemper, is a disease caused by the highly contagious canine distemper virus.

Distemper has been present in Ontario for at least 60 years. It is common and widespread in wildlife in Ontario, and infects mammals including:

  • coyotes
  • foxes
  • wolves
  • mink
  • skunks
  • raccoons
  • domestic dogs
  • ferrets

The canine distemper virus does not cause illness in humans, but humans can spread the virus to animals such as domestic dogs.

Distemper has a high mortality rate. However, wildlife populations do not seem to be affected long-term. Distemper occurs most often when animal populations are large or concentrated.

How the canine distemper virus spreads

Distemper is highly infectious. It can spread:

  • by contaminated air droplets through sneezing and coughing
  • through contaminated food, water and surface
  • in saliva, feces, and urine

Animals can spread the virus up to 90 days after they become infected, even if they aren’t showing signs of the disease.

Distemper, rabies and other wildlife diseases can be unintentionally spread when animals are moved from one area to another. This is why we generally require that wildlife be released within 1 km from where they are found. Raccoon rabies was reintroduced into Ontario in 2015 when an animal was inadvertently moved over 500 km from New York State.

Signs and symptoms of canine distemper

Distemper affects the immune, respiratory and neurological systems of infected animals. Distemper signs and symptoms can vary greatly between individual animals and species. Signs can include:

  • respiratory infection
  • runny nose
  • watery eyes
  • vomiting
  • diarrhea
  • fever
  • thickening of the foot pads

Neurological signs such as wandering aimlessly in a circle, paralysis, and disorientation are common.

Canine distemper and rabies

Many signs and symptoms of distemper are similar to rabies.

Animals can be infected with both distemper and rabies at the same time. This is called co-infection. If an animal is misdiagnosed and eventually released, it could spread both rabies and distemper.

Affected animals should only be handled by trained professionals because rabies is fatal to humans.

Learn more about rabies in wildlife.

Canine distemper treatment

There is no cure or effective treatment for distemper. Prevention is the best option.

Distemper can cause permanent neurological damage. Animals can also continue to spread the virus months after their symptoms disappear.


There is a highly effective vaccine which creates immunity to distemper. It is routinely given to domestic dogs.

While the distemper vaccine can prevent illness, it cannot cure an animal that is already sick.

The vaccine must be delivered by injection, which means it is not practical to vaccinate wildlife on a large-scale. An oral vaccine bait like the one used in rabies control operations is not currently available.

Protecting your pets

Domestic dogs and ferrets are highly susceptible to distemper.

Domestic cats can also contract the virus, but they are usually asymptomatic. This means they can carry the virus, but they do not become sick.

To protect your pets:

  • keep pet vaccinations for distemper and rabies up to date
  • supervise pets while you are outdoors and prevent them from interacting with wildlife
  • maintain a safe distance from wild animals and unfamiliar domestic animals

If you think your pet may have been exposed to distemper, contact your veterinarian.

What to do if you see sick wildlife

If you see wildlife acting strangely, or if you need to get help for a sick, injured or abandoned animal and the animal is alive, if can be done safely, keep track of the animal’s location and call one of the following:

  • your municipal animal control department (for non-emergencies in urban areas)
  • a private animal control agency or a licensed trapper in your area (for non-emergencies in urban and rural areas)
  • an authorized wildlife custodian (for sick, injured or abandoned animals)
  • your local ministry work centre (for non-emergencies and to get advice on who to call)
  • local police department or OPP detachment (in emergency or public safety situations).

If the animal is dead, call:


You can help prevent the spread of the distemper by:

  • maintaining a safe distance from wild animals and unfamiliar domestic animals
  • avoiding feeding or touching wildlife or their droppings
  • avoiding touching, handling or harassing wildlife (living or dead)
  • not trying to house, relocate, or rehabilitate wildlife unless you are authorized to do so
  • not moving wildlife more than 1 km from where they were found, if you are authorized to relocate wildlife
  • disposing of animal carcasses safely (consult your municipality for guidance)
  • the Canadian Wildlife Health Cooperative has recommendations for veterinarians and wildlife custodians to help reduce the transmission of wildlife diseases through translocation (PDF).