Distemper in dogs

Distemper in dogs

July 24, 2023

What is Canine Distemper Virus (CDV)?

Dogs distemper is a highly contagious viral disease and common in Hong Kong. It is caused by a virus which is shed in bodily secretions but especially from the respiratory tract. Unvaccinated dogs of any age are susceptible to CDV but particularly puppies.

The disease is spread mainly by direct contact between a susceptible dog and a dog showing symptoms. Coughing and sneezing can spread the virus.

Symptoms of CDV

Initially, infected dogs will develop some mild signs. These symptoms may go unnoticed and include fever, mild conjunctivitis and loss of appetite. As the virus attacks the nervous system, the infection symptoms may worsen showing respiratory and gastrointestinal signs which may be complicated by secondary bacterial infections:

▪ Respiratory: Sneezing and a clear nasal discharge which becomes thick and yellow; runny eyes. Soft moist cough which can progress to pneumonia.

▪ Gastrointestinal: Vomiting and diarrhea which quickly causes dehydration and electrolyte imbalances. These symptoms may then be followed by more serious neurological signs – fits or seizures, twitching, shaking, trembling and “chewing-gum fits”.

Some dogs may also develop erosions in their teeth (enamel hypoplasia) or hardness of their foot pads or nose (hyperkeratosis).

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How is CDV diagnosed?

As the symptoms of CDV are highly characteristic of the virus, vets can often make a diagnosis after examining your dog. Your vet may also perform a CDV antigen test. Sometimes blood tests and x-rays may be used to help in the diagnosis.


Currently there are no antiviral medications to treat canine distemper. Treatment is aimed at controlling secondary bacterial infections with supportive care:

  • Provide a clean, warm and draught free environment for your pet.
  • Any discharge from the nose and eyes should be gently bathed as necessary with warm salty water.
  • Vapourization and humidification are important so when having a hot shower take the dog with you into the bathroom (away from the water). The steam will help to soothe the airways. Adding eucalyptus oil or “Vicks Vaporub” into a mug of hot water in the shower can also help with the congestion in your dog’s lungs.
  • Maintaining hydration and energy is important too. Your vet may prescribe an oral rehydration powder which should be mixed with water as directed. This can be fed regularly after warming to body temperature.
  • Your vet may prescribe a convalescence diet, which can also be warmed and syringe fed. Moreover, your vet may prescribe antibiotics to combat any secondary infection or anti-diarrheal/ anti-emetics to decrease diarrhea and vomiting.
  • It is important to follow all instructions carefully and never to overdose. Please finish the course of any medication given and attend check-up appointments as recommended.
  • Isolation from other dogs is vital to prevent the spread of disease. Any unvaccinated (but healthy) dogs in the household should be vaccinated as soon as possible. Cats and humans can’t catch CDV.

The prognosis depends on the strain of CDV and your dog’s immune system. Half of all dogs infected with CDV will die due to dehydration or neurological symptoms. This figure is much higher in puppies and up to 80% may die despite treatment. Also, as discussed earlier, some effects of CDV such as hard-pad, fits and enamel hypoplasia, may persist for many years after the initial infection. Dogs that recover will shed the virus for several weeks after the infection but do not continue to shed the virus for life.


CDV is easily prevented by proper vaccination. This means two or three vaccinations during puppy period starting around 6 to 8 weeks old and Your vet will help you determine how often your dog should receive booster vaccine after the primary course.

Prevent your dog from being in close contact with other puppies. When your puppy is young it is highly susceptible, and even vaccination does not give 100% protection. If your dog has distemper, it is infectious, and should be isolated from any susceptible dogs.

If you have any enquires about the vaccination, or need more advice, please contact us, or make an appointment for consultation


Distemper in Dogs@VCA hospitals

Canine Distemper@AVMA

Canine Distemper Virus@citypetsvets

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