Distemper in Dogs: What You Should Know

Distemper is a cruel disease. Even if the dog survives the acute illness, brain damage and seizures may follow.

If you suspect distemper in your dog, see your veterinarian right away. Photo: scott1346

At the mention of distemper, an image pops into my mind of a sad-looking Labrador puppy with his eyes gummed shut and a snotty nose.

Even though I saw this pup several years ago, the memory of his enduring patience in the face of a horrible illness still stays with me.

Distemper in dogs is a particularly cruel disease because if the dog survives the acute (sudden onset) illness, he may be left with brain damage and seizures. Happily, this was not the case for my Labrador patient, who went on to make a full recovery.

Symptoms of Canine Distemper

The first clues are:

  • Coughing
  • Sneezing
  • Sticky eyes

Those symptoms are followed by vomiting and diarrhea.

Not all dogs become seriously ill, and those with a strong immune system may even fight off the distemper virus altogether. The seriousness of the infection depends on age (puppies are more vulnerable), the dog’s health and the strain of the virus (some are more virulent than others).1

Unfortunately, the sticky discharge from the eyes can glue patient’s eyelids together. His nose becomes bunged up and he must breathe through his mouth. The virus travels to his lungs, and the damage can be so bad that the dog develops pneumonia. Then, as if that wasn’t enough, the virus multiples in his gut cells to cause sickness and diarrhea.

If the patient survives this phase, a nasty surprise can be waiting in the form of neurological symptoms. Unchecked by the immune system, the virus spreads to the brain and these symptoms show weeks after an apparent recovery from the chest and tummy signs.

Neurological symptoms may include:

  • A head tilt
  • Poor balance
  • Clumsiness
  • Or even seizures

Seizures can vary from mild, localized “chewing gum”–type movements of the jaw to full-blown fits.

When I was being trained, a wiser veterinarian than me said he could always tell when an old distemper dog walked into the clinic from the clicking sound of his pads on the floor. What my colleague was referring to was the “hard pad” by which distemper is also known. This hardening of the horn layers of the pads and nose is distemper’s final calling card — a sign that the dog has been ill, survived and then developed the late-onset symptom of hard pads.

What Causes Distemper?

Distemper is caused by the canine distemper virus (CDV), which despite its name can cause disease in other species such ferrets, seals and even porpoises.

The virus is able to live in lymph, epithelial and nervous tissue, which means infection can spread via moist breath, saliva, urine and feces. A non-immune dog in contact with the virus may start to be ill 5 to 14 days later.2

In the quick video below, Melissa Kennedy of the University of Tennessee Veterinary Medical Center discusses more:

YouTube player


Most times your veterinarian will make a diagnosis based on the clinical signs alone. Lab tests can confirm the diagnosis, but this doesn’t alter the treatment and the tests often are not prioritized. Your vet will get clues from a general blood screen picture that shows a shift in certain white cell lines that point to viral infection. Likewise, chest radiography can help rule out other conditions, such as heart disease, as the reason for the cough.

Part of the problem with specific lab tests is that the gold standard depends on spotting viral inclusions within infected cells. However, these inclusions are present only for a limited time and are easily missed.

Other tests include measuring the body’s immune response to the distemper virus. A rising level of antibody to CDV, identified by testing 2 blood samples, taken 2 to 3 weeks apart, gives a fairly heavy hint — but there is some cross reaction with vaccines strains, so even these results are not conclusive.

A virus causes distemper, and the body’s immune system works to fight it off.


Distemper in dogs is caused by a virus, and it is the body’s immune system that combats illness, rather than a drug cure. Treatment is supportive care, such as antibiotics for pneumonia and intravenous fluids if the patient is dehydrated.

Good nursing is important, and simple things such as cleaning the eyes and nose make the patient more comfortable. If the dog recovers and then has fits, he may be prescribed anticonvulsants.

How to Prevent Distemper

If you know of an infected dog in the area, don’t worry. The virus survives in fluids only for about 20 minutes and is killed by common disinfectants.

Distemper can be prevented by regular vaccination. Most vaccine manufacturers recommend that pups receive their first shot around 6 to 8 weeks old, and a second at 10 to 12 weeks. This is followed by a booster a year later, and then every 2 years after that. The good news is that if you regularly vaccinate your dog, he doesn’t have to be ill like that poor Labrador I treated all those years ago.

Additional Resources


  1. Clinical Medicine of the Dog and Cat. Michael Schaer. Publ: Manson Publishing.
  2. Small Animal Internal Medicine. Nelson & Couto. Publ: Mosby. Third edition.