Dog: Distemper

General information

Other common/scientific names: canine distemper virus, CDV, hard pad disease


Distemper is a highly contagious, often fatal viral disease caused by the canine distemper virus (CDV). This virus is a Morbillivirus which is closely related to the human measles virus. All animals in the canine family are susceptible to CDV including fox, coyote, wolf, ferret, skunk and badger. This virus affects multi-organs in the respiratory, gastrointestinal and central nervous systems. Canine distemper virus has the ability to produce a latent infection meaning the virus can remain dormant in the dog without producing any visible signs.

While all dogs are at risk of acquiring distemper, most cases in the US involve puppies. Maternal (from the mother) immunity begins to wan at four months of age, leaving a puppy vulnerable to distemper if not vaccinated. Older unvaccinated dogs or dogs with weakened immune systems are also susceptible to distemper. The typical distemper suspect is a rescue, shelter or pet store puppy with questionable vaccination history.


Canine distemper virus is spread through respiratory secretions from infected, coughing dogs. It can also be spread through the urine and feces of infected dogs. The virus enters the uninfected dog through the nose or mouth and travels to the lymph nodes in the lungs. From the lymph nodes, the virus moves into the blood stream causing a viremia and then invades the different body systems. Unborn puppies can acquire the infection from their mother while still in the uterus.

The canine distemper virus has a long incubation period of 9 to 14 days from the time the dog is exposed until it starts to show clinical signs. It does not survive long in the environment and is susceptible to routine disinfection and cleaning.


The clinical signs of distemper will depend on which body system the virus has infected. The first sign of distemper is usually a discharge from the eyes that is watery or pus-like. This is followed by a fever, nasal discharge, coughing, lethargy, reduced appetite, vomiting and diarrhea. Dogs with distemper may develop a secondary bacterial pneumonia. The skin on the nose and footpads may become thickened and hyperkeratotic or hard (“hardpad” disease). Puppies which recover from distemper have damage to their dental enamel resulting in brown, discolored teeth. In later stages, the virus may attack the nervous system causing twitching, seizures and paralysis. As part of the neurologic signs, the dog may show chewing movements of the jaw or “chewing-gum fits” which is a classic sign of distemper. Distemper is often fatal. Even if a dog does not die from the disease, CDV can cause irreparable damage to a dog’s nervous system.


Diagnosis of distemper is based on history, clinical signs and laboratory tests. Because the distemper virus can be elusive, a negative test does not rule out distemper. Cells from the conjunctiva, blood or tissue can be examined under a microscope for canine distemper virus. Blood tests to determine a dog’s antibody levels to canine distemper virus can aid in the diagnosis. Other tests to detect distemper virus DNA can be used for diagnosis.


There is no specific treatment or drug available to kill the virus in infected dogs. Dogs with distemper will need to be hospitalized for supportive care. Intravenous fluids to prevent dehydration, antibiotics to prevent secondary infections and medications to reduce vomiting and diarrhea are used. Sick dogs should be kept warm, receive good nursing care and hygiene and be isolated from other dogs. Most veterinarians recommend euthanasia for dogs that suffer from severe neurologic complications.


Prognosis depends on the strain of canine distemper virus and the dog’s immune response. Dogs with severe signs of distemper rarely recover. Dogs with a strong immune system and mild signs can recover from distemper.


Effective vaccination for prevention of canine distemper has been available since the 1950s. Prior to widespread vaccination, distemper was very common resulting in many canine deaths. Puppies should be vaccinated for canine distemper beginning at 6 to 8 weeks of age and boostered every 2 to 4 weeks until 16 weeks of age. After the initial puppy series, an annual vaccine is recommended. Subsequent vaccination boosters are given every 1 to 3 years depending on your veterinarian’s recommendation. Canine distemper vaccination is most commonly included in a combined vaccine with canine parvovirus, canine parainfluenza, canine hepatitis, Leptospirosis and coronavirus.

Click here for more information on canine vaccinations.


A recovered dog may shed the virus for 2 to 3 months. It is important to keep these dogs separated from uninfected dogs.

Update version: 4/24/2014, © Copyright by
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