Distemper in Dogs: Signs, Spread and Why Vaccination Matters

Distemper in dogs is a serious viral illness. The PDSA describes it as a nasty virus that attacks several organs, including the guts, heart, immune system, lungs, brain and nerves, and says young, unvaccinated dogs are most at risk. Vaccination means it is now rarely seen in the UK, but it does still occur, so if your dog shows symptoms, contact your vet.

At a glance

• What it is: a serious viral infection that can affect several body systems.
• Who it affects: young, unvaccinated dogs are most at risk.
• Urgency: when signs appear. The PDSA says to contact your vet if your dog starts showing symptoms, especially if they have not been vaccinated.
• Vet needed? Yes, always.

Signs to look for

The PDSA lists fever, runny eyes and nose (watery at first, then pus-like), low energy, loss of appetite, diarrhoea and coughing. Later, some dogs develop thickened paw pads and nose, known as “hard pad”, along with tremors, paralysis and fits and seizures. The PDSA says distemper often starts with runny eyes, a cough and diarrhoea, and that hard pads and nervous signs can appear around three to four weeks in. If you ever see your dog have a fit, speak to your vet.

Because the early signs overlap with many other illnesses, our guides to sick dog symptoms and why your dog is coughing are useful starting points, but only a vet can tell what is going on.

Causes and risk factors

Distemper is caused by a virus, so antibiotics do not work against it, as the PDSA explains. The PDSA says it spreads through the air, through body fluids such as urine and saliva, and through the environment an infected dog has been in.

Unvaccinated young dogs are the main risk. The PDSA says distemper is much rarer in the UK than it used to be because of vaccination, but it still occurs, especially where many dogs are unvaccinated. That is why keeping up with vaccinations matters even when you have never heard of a local case.

When to call your vet

The PDSA advises contacting your vet if your dog starts showing symptoms of distemper, especially if they have not been vaccinated. If you are unsure, speak to your vet. If you need a practice, see our vets guide.

How vets diagnose it

The early signs can look like those of other common illnesses, which is why a vet needs to examine your dog and work out what is going on. Cornell University’s vet school says distemper can be hard to recognise at first for exactly this reason, and a peer-reviewed study (Sarchahi and colleagues, 2022) states that a diagnosis cannot be made from clinical signs and blood count results alone, so lab tests are also needed.

Cornell describes PCR, a lab test that detects the virus’s genetic material, as the test of choice. The 2022 study looked at samples of spinal fluid, blood and swabs from the mucous membranes, and found that which sample works best depends on how the illness has progressed. Your vet will decide whether any tests are needed and which ones. You can read more on the Cornell canine distemper page.

What vets generally do about it

Treatment is decided by your vet. The PDSA says treatment involves supporting your dog’s body while they try to fight the infection, and that antibiotics do not work against the virus itself.

Outcomes vary. The PDSA says some dogs die early, some are put to sleep because of their poor condition, some are left with permanent brain damage and some recover after several weeks. It adds that once a dog has had distemper, they may suffer relapses and problems throughout life. Treatment can be very expensive, so the PDSA suggests discussing costs openly with your vet and considering pet insurance before illness starts; see our pet insurance guide.

Living with it and prevention

The PDSA says vaccination is the best way to protect your dog from distemper. Puppies should be vaccinated before they mix with other dogs, and adult dogs need boosters throughout life. A puppy that has not finished its course can go in your own garden if no unvaccinated dogs have visited recently, and should be carried in public places rather than put on the ground. The PDSA says puppies can start walks and meeting other dogs 1 to 2 weeks after finishing the first vaccination course.

The BSAVA’s vaccination position statement lists distemper as a core vaccine, meaning one that should be considered for all dogs. It says a primary course is usually at least two doses given 2 to 5 weeks apart, with a booster a year later, and that for most UK-authorised dog vaccines, revaccination against distemper is at least every 3 years. Products differ, so speak to your vet about the right schedule for your dog. Browse the full list on our dog illnesses A to Z.

Related conditions

• Parvovirus in dogs
• Kennel cough in dogs
• Infectious canine hepatitis
• Leptospirosis in dogs
• Epilepsy and seizures in dogs

Sources

• PDSA, Distemper in dogs
• BSAVA, Vaccination (position statement)
• Cornell University College of Veterinary Medicine, Canine distemper virus
• Sarchahi A. A., Arbabi M. and Mohebalian H., Detection of canine distemper virus in cerebrospinal fluid, whole blood and mucosal specimens of dogs with distemper using RT-PCR and immunochromatographic assays, Veterinary Medicine and Science, 2022

This page is general information, not veterinary advice. If you are worried about your dog, speak to your vet. Written by Georgiana & Figo, who are dog owners, not vets. Have a look around Calmshops for everyday dog essentials.