Summary

Expert advice from Dr Felicia:

Canine distemper is rare in vaccinated dogs, but puppies are at risk and tend to be more severely affected. Puppies also deteriorate quicker when ill because they lack energy and fat reserves, so get your pup to the vet ASAP if things don’t seem right.

What is canine distemper?

Canine distemper is a serious infectious disease caused by canine distemper virus, a morbillivirus related to the virus that causes measles in people.

The virus initially infects tissues associated with the respiratory and immune systems before spreading through the body. It can affect the lungs, gastrointestinal tract, urinary and reproductive tissues, eyes and central nervous system.

Disease severity varies considerably. Some dogs develop relatively mild systemic illness, while others develop severe pneumonia, gastrointestinal disease or neurological complications. Puppies and dogs that have not been appropriately vaccinated are at greatest risk.

How is canine distemper spread?

Canine distemper is spread primarily through respiratory droplets and secretions from an infected animal, for example when an infected dog coughs or sneezes.

The virus can also be present in other body fluids and secretions, including urine. Close contact with infected animals therefore represents the greatest risk.

Canine distemper virus is relatively fragile outside the body compared with viruses such as parvovirus, so contaminated objects are a less important route of transmission than direct or close contact. Nevertheless, good hygiene and disinfection remain important where an infected dog has been housed.

Infected dogs may begin shedding virus before all clinical signs are obvious and some continue shedding for several months. Dogs with confirmed or suspected distemper should therefore be kept away from susceptible dogs until their veterinarian advises that isolation is no longer necessary.

What other animals can catch canine distemper?

Canine distemper virus can infect a number of other species, including foxes, wolves, ferrets and some other wild carnivores. This can complicate control of the virus because wildlife can contribute to its circulation.

Symptoms of canine distemper

Symptoms can vary because canine distemper affects several different body systems.

Early or systemic signs may include:

• fever
• lethargy and weakness
• reduced appetite
• discharge from the eyes or nose
• conjunctivitis
• coughing
• pneumonia or difficulty breathing
• vomiting
• diarrhoea
• dehydration

Some surviving dogs develop thickening of the nose and footpads, sometimes referred to as “hardpad disease”. Puppies infected while their adult teeth are developing may also develop enamel abnormalities.

Neurological symptoms of canine distemper

Neurological disease is one of the most serious complications.

Signs can include:

• repeated muscle twitching, particularly of the face or limbs
• wobbliness or loss of coordination
• circling
• head tilt
• abnormal eye movements
• weakness or paralysis
• seizures

A characteristic type of seizure can involve repetitive jaw movements sometimes described as “chewing-gum fits”.

Importantly, neurological signs do not always appear at the beginning of the illness. They may develop alongside respiratory or gastrointestinal symptoms, later in the disease, or even after a dog appears to have recovered from the initial systemic illness.

Neurological involvement generally carries a more guarded prognosis and some surviving dogs have permanent neurological abnormalities.

When should you see a vet?

An unvaccinated or incompletely vaccinated puppy or dog showing fever, marked lethargy, respiratory discharge, coughing, vomiting or diarrhoea should be assessed promptly.

Seek urgent veterinary attention if your dog develops:

• difficulty breathing
• repeated seizures
• collapse
• marked weakness or inability to walk normally
• persistent vomiting or diarrhoea with dehydration
• rapidly worsening neurological signs.

Young puppies have limited fluid, fat and energy reserves and can deteriorate particularly quickly when seriously ill.

How is canine distemper diagnosed?

Canine distemper cannot reliably be diagnosed from symptoms alone because respiratory, gastrointestinal and neurological signs can occur with several other infections and diseases.

Your veterinarian will consider your dog’s symptoms, age, vaccination status and potential exposure before selecting appropriate tests.

Tests may include:

Complete blood count and blood chemistry
Blood testing can identify changes such as reduced white blood cell numbers and can assess hydration, electrolytes and organ function.

RT-PCR testing
Reverse transcriptase polymerase chain reaction testing can detect viral genetic material. Depending on the individual case, samples may include conjunctival or nasal swabs, blood or urine.

Antibody testing
Serological testing can help identify an immune response to the virus, but interpretation may be complicated by previous vaccination and the stage of infection.

Chest X-rays
Radiographs may be recommended where pneumonia or other respiratory complications are suspected.

Additional neurological testing
Dogs with neurological signs may require additional tests, including cerebrospinal fluid analysis or advanced imaging in selected cases.

Expert advice from Dr Felicia:

Tests performed for acutely unwell dogs include specific diagnostics to ideally confirm the disease that is causing the signs, as well as testing of electrolytes, blood cell counts and organ function to be able to tailor and monitor treatment accordingly.

How is canine distemper treated?

There is currently no antiviral treatment that reliably eliminates canine distemper virus, so veterinary care focuses on supporting the dog while their immune system fights the infection and managing complications as they occur.

Depending on the severity of illness, treatment may include:

• intravenous fluids and electrolyte replacement
• nutritional support
• medication to control vomiting
• pain relief and fever management
• oxygen and respiratory support where required
• anticonvulsant medication for seizures
• antibiotics for secondary bacterial infections
• intensive nursing care

What is the prognosis for a dog with distemper?

The outlook varies considerably. Dogs affected mainly by respiratory or gastrointestinal disease may recover with appropriate supportive care and an effective immune response.

The prognosis becomes more guarded when neurological signs develop. Neurological disease can be progressive, and some dogs continue to develop new signs after their respiratory or gastrointestinal symptoms have resolved. Permanent muscle twitching, seizures or other neurological abnormalities can remain in survivors.

In dogs with severe, progressive neurological disease and poor quality of life, euthanasia may unfortunately need to be considered.

How can canine distemper be prevented?

Vaccination is the best way to prevent canine distemper.

Canine distemper virus vaccination is considered a core vaccination, meaning that it is recommended for dogs because distemper is a potentially severe, life-threatening disease with widespread distribution. The Australian Veterinary Association supports core vaccination while recommending that the exact schedule be tailored by the veterinarian to the dog’s age, health, exposure risk and the vaccine being used.

Puppies require a series of vaccinations because antibodies received from their mother can interfere with early vaccine responses.

The current 2024 WSAVA guidelines recommend giving puppy core vaccines every 2–4 weeks, with the final puppy dose at 16 weeks of age or older. They also recommend either antibody testing from around 20 weeks or an additional core vaccination at or shortly after 26 weeks to cover the small proportion of puppies in which maternal antibodies may still have interfered with the earlier vaccine.

Once a dog has mounted an appropriate immune response to modern modified-live core vaccines, WSAVA advises that subsequent CDV core revaccination need be given no more frequently than every three years, although the schedule should follow the product used and the individual veterinarian’s advice.

Learn more about Dog and Puppy Vaccination schedules and dog vaccination costs to help prevent canine distemper.

Can titre testing be used for canine distemper?

Yes. Canine distemper is one of the core diseases for which antibody testing can provide useful information about protection.

WSAVA states that the presence of antibodies against canine distemper virus in an adult dog that has mounted its own immune response is generally considered evidence of protective immunity. Serological testing may be particularly useful where there is uncertainty about revaccination because of immunosuppressive treatment or a previous significant vaccine reaction.

A negative antibody result may indicate that the dog is not adequately protected and vaccination may therefore be recommended.

Expert advice from Dr Felicia:

If you’re unsure when your dog was last vaccinated, vets can usually provide a vaccination record. If you’re uncertain about vaccinating due to illness or immunosuppression, titre testing can help assess whether protective antibodies are present and whether revaccination may be required.

How long should a dog with distemper be isolated?

Dogs with confirmed or suspected canine distemper should be isolated from other susceptible dogs while they may be infectious.

Some dogs continue shedding canine distemper virus for weeks or even months after apparent recovery, so there is no single safe “one month” rule that applies to every dog. Your veterinarian should advise when contact with susceptible animals can safely resume.

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Conclusion

Canine distemper is now uncommon in appropriately vaccinated pet dogs, but it remains a serious and potentially fatal disease in unvaccinated and incompletely vaccinated animals, particularly puppies.

Because the virus can affect the respiratory, gastrointestinal and nervous systems, symptoms vary considerably and neurological complications may sometimes appear after the initial illness seems to have improved.

There is currently no specific cure, so treatment focuses on supporting the dog and treating complications while their immune system responds to the infection. Vaccination remains by far the most effective protection.

If you are unsure whether your puppy or adult dog is fully vaccinated against canine distemper, ask your veterinarian to review their vaccination record and advise whether vaccination or, in selected circumstances, antibody titre testing is appropriate.

Sources:

“Canine Distemper”, Merck Veterinary Manual, updated 2026. https://www.merckvetmanual.com/infectious-diseases/canine-distemper/canine-distemper. Accessed 20 October 2026.

“Canine Distemper (Hardpad Disease)”, Merck Veterinary Manual, updated 2026. https://www.merckvetmanual.com/dog-owners/disorders-affecting-multiple-body-systems-of-dogs/canine-distemper-hardpad-disease. Accessed 20 October 2026.

Squires RA, Crawford C, Marcondes M, Whitley N. “2024 guidelines for the vaccination of dogs and cats”, Journal of Small Animal Practice / World Small Animal Veterinary Association, 2024. https://wsava.org/wp-content/uploads/2024/04/WSAVA-Vaccination-guidelines-2024.pdf. Accessed 20 October 2026.

“Vaccination of dogs and cats”, Australian Veterinary Association. https://www.ava.com.au/policy/vaccination-of-dogs-and-cats. Accessed 20 October 2026.