Canine Distemper: Signs, Treatment and Prevention

Canine distemper is a serious viral disease of dogs. It can affect the eyes, nose, lungs, gut, skin and brain, and it has no cure. Even so, a routine vaccine protects dogs very well. Where most dogs are vaccinated, distemper has become rare.

Puppies younger than four months and dogs that were never vaccinated are most at risk. That is why distemper matters so much in rescue work, where dogs often arrive with no health records.

What distemper is

The disease is caused by canine distemper virus, a close relative of the virus that causes measles in people. The virus attacks the immune system first. This leaves the dog open to other infections. The virus then moves on to the airways and the gut and, in some dogs, to the brain and nerves.

Ferrets and many wild animals can catch it too. In Europe these include foxes, wolves, badgers, martens and otters. The virus passes both ways between wildlife and dogs that are not vaccinated.

Signs to watch for

The first sign is often a short fever a few days after infection, and it is easy to miss. The dog may then seem better for a while before it falls ill again. Signs you may see include the following.

• Watery or thick, pus-like discharge from the eyes
• A runny nose, often with thick discharge
• Fever, tiredness and poor appetite
• Coughing or fast, labored breathing
• Vomiting and diarrhea
• Thick, hard skin on the nose and paw pads, which gave the disease the old name hard pad disease
• Muscle twitches, a head tilt, circling, stumbling or weak legs
• Seizures, sometimes with chewing movements of the jaw and drooling

Nervous system signs may show up together with the other signs. They can also start one to three weeks later, or even weeks to months after the dog seemed to be getting better. Not every dog shows every sign. Some dogs have only a mild illness that looks like an ordinary cough.

Puppies that get distemper before their adult teeth come in can be left with thin, pitted tooth enamel for life. If your adopted dog has teeth like this, you can mention it to your vet, since it may point to an illness in puppyhood.

When it is an emergency

Call your vet the same day if a puppy or an unvaccinated dog has eye or nose discharge along with fever, low energy or poor appetite. Distemper can get worse quickly in young dogs.

Go to a vet or an emergency clinic right away if your dog has a seizure, has trouble breathing or collapses. The same applies to a puppy with repeated vomiting and diarrhea, a dog that stops eating and drinking, or a dog with new twitching, stumbling or leg weakness.

If you think it may be distemper, call the clinic before you arrive. The team can then keep your dog away from other patients.

How vets diagnose and treat it

Distemper can look like several other infections, including kennel cough. A vet usually combines the dog's history, a physical exam and lab tests. A common test looks for the virus's genetic material in swabs from the eyes or nose, or in blood or urine. A recent vaccination can affect some test results, so tell the vet about any shots your dog has had.

Distemper has no cure, and no drug is approved to kill the virus. Treatment supports the dog while its own immune system fights the infection. Depending on the case, the vet may give fluids, medicine for nausea and diarrhea, antibiotics for bacterial infections that take hold, feeding support and medicine to control seizures. Sick dogs are kept in isolation, away from other dogs.

The outlook depends on how severe the illness becomes. Some dogs recover fully. Nervous system signs make a full recovery less likely, and some survivors keep twitches or seizures for life. When a dog has severe nervous system disease that keeps getting worse, the vet may talk with you about euthanasia. Dogs that recover are usually protected against distemper for life.

If your vet sends your dog home to recover, the care plan usually includes keeping it away from other dogs, including dogs in your own home. Bowls, bedding and floors can be cleaned with a disinfectant your vet suggests. Please ask the vet before giving any home remedy or supplement.

How it spreads

Most dogs catch distemper by breathing in droplets from an infected dog or wild animal. Coughing, sneezing and barking send these droplets into the air. The virus is also found in saliva, urine and other body fluids, so shared bowls, bedding and toys can pass it on too. A pregnant dog can pass it to her unborn puppies.

Infected dogs can shed the virus a few days before they look sick. Many shed it for weeks, and some keep shedding it for months after they seem to have recovered. This is how distemper can move quietly through a group of dogs.

The virus is fragile outside the body, and most household disinfectants kill it. It survives longer in cold weather.

How to prevent it

Vaccination is the best protection. The distemper vaccine is a core vaccine, which means vets recommend it for every dog. It usually comes in a combination shot that also protects against other serious viruses, such as parvovirus.

Puppies need a series of shots, because antibodies from their mother can block the vaccine in the first weeks of life. International vaccination guidelines advise starting at six to eight weeks of age, repeating every two to four weeks, and giving the last puppy shot at 16 weeks of age or later. A booster usually follows at about six months or one year, then every three years or as your vet advises. An adult dog with no vaccination record can be vaccinated at any age. Your vet will set the exact schedule for your dog.

A few everyday habits add to that protection.

• Until the puppy series is done, take care in busy dog places such as parks, kennels, pet shops, classes and grooming salons.
• When you book a kennel, daycare or training class, check that it asks every dog for current vaccinations.
• Keep your dog away from sick dogs and from wildlife. Wild animals with distemper may lose their fear of people and move in an odd, unsteady way. Rabies can look the same, so it is safest to keep your distance and report such an animal to local veterinary services.

Careful socializing with healthy, vaccinated dogs can still begin before the puppy series ends. Ask your vet how to do it safely.

Other pets and people

People do not catch canine distemper. The virus can still travel for a short time on hands, clothes and shoes. Washing your hands and changing your clothes after caring for a sick dog helps protect other dogs.

Cats can be infected, but they are unlikely to get sick. The illness often called feline distemper is a different disease caused by a different virus, feline panleukopenia virus. Cats need their own vaccine against it.

For ferrets, distemper is even more dangerous and nearly always fatal. Ferrets can be vaccinated too. If you keep ferrets and dogs, ask your vet which vaccine suits each of them.

Why it matters for rescued and adopted dogs

Distemper still circulates in Southern and Eastern Europe. In Croatia, a 2023 study found the virus in wild red foxes. In southern Italy, researchers found it in stray and household dogs, and more often in dogs imported from other countries. In Switzerland, some rescue dogs imported from Hungary kept shedding the virus for months after their signs had stopped. A 2024 study of vaccinated shelter dogs in Bulgaria found good antibody levels in most of them, while about one in nine had not built enough.

This is why the first weeks matter. At Paw Squadron, the first stops after every rescue are the vet and a bath. Each animal gets a checkup, deworming and treatment against fleas and other parasites. Before adoption, every animal also gets a checkup, treatment, vaccinations and a microchip.

In the first days after your new dog comes home, it is a good idea to see your own vet and bring the vaccination records. Your vet can check which shots were given and plan any that are still due, such as the rest of a puppy series or the next booster. In some cases the vet may suggest a blood test to check the dog's antibody levels. Travel and a new home are stressful, and stress can make a dog more likely to fall ill. Watch your new dog closely for the first few weeks, and tell your vet early about eye or nose discharge, coughing, diarrhea or twitching.

If you are thinking about adopting, you can meet the dogs waiting for homes on our Adoptions page. For more health guides, browse PawPedia.