Canine Distemper Virus

Distemper is a very contagious disease of dogs. Outbreaks are uncommon these days because so many dogs are now vaccinated. However it still exists, so individual unvaccinated dogs and kennels occasionally succumb to this distressing and often fatal disease.

Expand All
  • Distemper is a disease caused by the Canine Distemper Virus, which is closely related to the measles virus seen in humans. It primarily affects dogs, but in Europe, other animals, such as foxes and ferrets can be affected. The virus is usually spread by direct contact with affected dogs, however although relatively unstable in the environment, the virus can be carried on clothing and subsequently infect any in-contact unprotected dogs.

    The virus is shed in aerosol drops from eye and nasal discharges and may be shed for several months post infection. Spread is very rapid in any group of dogs, especially in kennels and at dog shows, hence the necessity to vaccinate dogs. Like canine viral hepatitis, introduction of an infected puppy to a kennels is the most common source of an outbreak. Puppies from unvaccinated mothers, unvaccinated dogs and the immunosuppressed are most at risk.

    The infection begins by attacking the respiratory system, but in time many organs may become infected, including the brain.

  • In the days following infection, the first sign seen is a fever which may only last a few days. This is then followed by a second fever which lasts longer and is accompanied by other signs.

    Minor form Many dogs will have partial immunity, either from their mother, or from a lapsed booster. They might only show slight malaise, perhaps with runny eyes and nose and a cough. It is these dogs that are most likely to spread the full disease to unprotected dogs in the community.

    Various forms of the disease exist:


    Respiratory form: Characterised by difficulty in breathing, nasal discharge, sneezing and coughing. Secondary bacterial infection is possible.
    Digestive form:  Vomiting and diarrhoea are seen.
    Cutaneous form:  A dermatitis with a thickening of the skin on the nose and pads (hence the old name of “hardpad”). This form may be associated with nervous signs.
    Nervous form: Fits or gradual twitching of the muscles and paralysis of the limbs (“chorea”) can be seen. This may be coupled with a characteristic half-cough caused by nerve damage. In this form, the initial disease has often passed unnoticed.
    Ocular form:  Signs of conjunctivitis (runny eyes) may be accompanied by other more subtle ocular changes.


  • Although Canine Distemper is difficult to diagnose definitively, a presumptive diagnosis can sometimes be made using a combination of clinical signs and some diagnostic tests. Certain samples from the dog, including blood, spinal fluid, nasal secretions and other tissue samples can be taken to help with diagnosis. However, as there is no fully reliable test, absolute confirmation may be impossible.

  • The causative virus cannot be treated. Any secondary bacterial infections are treated alongside supportive treatment care:

    • Antibiotic treatment to control any bacterial infections, if present.

    • Medication to control symptoms, such as diarrhoea, vomiting, coughing and seizures.

    • Nursing care to keep dog clean and comfortable; remove excessive ocular and nasal discharges etc.

    • Support to encourage eating and drinking.

    • Anti-inflammatories.

    Infected and in-contact dogs must be isolated from other susceptible dogs and strict hygiene precautions are necessary to prevent spread. Unfortunately treatment is not always successful, and the prognosis is especially poor for dogs that show neurological signs.

  • Prevention is by vaccination. The distemper component should always be included in the primary vaccination course given to puppies, and is often included in routine booster vaccinations.

    Based on your pet’s specific situation, your veterinary surgeon will decide the best vaccination protocol to meet your pet’s needs. An up-to-date vaccination is obligatory before going to dog shows and many kennels.

    In the event of an outbreak of disease, strict isolation and hygiene precautions must be instituted.