Canine distemper

What is it?

Canine distemper is a serious and highly contagious viral disease that mainly affects dogs, but also ferrets. It attacks several systems of the body, including the respiratory, digestive and nervous systems. This disease can be fatal, especially in young, unvaccinated animals.

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Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Causes and risk factors

The disease is caused by a virus called canine morbillivirus, which is close to the human measles virus. This virus attacks the animal's immune system, making it vulnerable to other infections. It spreads quickly in environments where many unvaccinated animals live.

Unvaccinated puppies and young animals are most vulnerable to this disease. Lack of vaccination, living in a community with other animals, and a weakened immune system also increase the risk of infection. Crowded environments like shelters also encourage the spread of the virus.

Transmission

The virus is mainly transmitted by air, through respiratory secretions of infected animals such as coughs or sneezes. Direct contact with a sick animal or contaminated objects can also promote contagion. Puppies and young ferrets are particularly exposed in collective places such as shelters or breeders.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

Treatment

There is no medication that destroys the canine distemper virus. The veterinarian therefore relies mainly on supportive care, to help the body defend itself.

The animal is often isolated, because it remains contagious. Hospitalisation is common in severe cases.

The veterinarian may place the animal on an intravenous drip to combat dehydration. Medications against vomiting and diarrhoea may also be used, along with nutritional support.

Antibiotics are prescribed to treat the bacterial infections that develop alongside the disease, because the virus weakens the immune defences. They do not act on the virus itself.

If nervous signs appear, medications against seizures may be used. The prognosis remains guarded, especially when the nervous system is affected.

Never give any medication without veterinary advice.

Prevention

Vaccination

A vaccine exists for dogs and ferrets. It is one of the so-called core vaccines. For dogs, it is most often combined with other vaccines in a single injection.

Puppies receive a series of closely spaced injections from a young age, because the mother's antibodies can interfere with the vaccine response. A booster is then given according to the schedule chosen by the veterinarian.

Ferrets can also be vaccinated, with a vaccine suited to their species. Never use a vaccine without veterinary advice.

For the other wild species mentioned, vaccination applies to specific situations (zoological parks, rescue centres). It must be decided by a veterinarian.

Possible complications

The virus weakens the animal's immune defences. Secondary bacterial infections are common, including pneumonia.

Dehydration and weight loss can become severe due to vomiting and diarrhoea.

Involvement of the brain and spinal cord may occur during the illness or later. It causes seizures, tremors, gait disorders or paralysis.

Some recovered animals keep sequelae: tics or muscle twitching, lasting nervous disorders, and dental problems in young animals affected while their teeth are developing.

The disease can be fatal, especially in unvaccinated young animals.

When to see a veterinarian

References

MSD Veterinary Manual

WOAH — Organisation mondiale de la santé animale (ex-OIE)

Content reviewed by the TunisieVet editorial team · Updated 03 November 2026