Distemper in Dogs: Signs, What to Do Today, Treatment and Vaccination

If you are reading this because a puppy or an unvaccinated dog is sick right now, I'd do these things in this order. First, check what you know about the dog's vaccines. Second, separate the dog from every other dog in your home and from public spaces. Third, phone your veterinarian or an emergency clinic and say plainly that distemper is possible. The clinic can tell you how to come in so the dog does not pass the virus to other patients, and they may ask you to wait in the car or use a side door.

Keep shared bowls, bedding, toys and grooming tools away from other animals until the veterinarian tells you more, as Cornell and the AVMA's 2022 owner brochure advise. Please do not give medicine or home remedies unless the veterinarian directs it.

A runny nose alone does not mean distemper. A veterinarian uses the dog's age, vaccine history, exposure and how the illness has progressed, then confirms with lab tests.

Distemper does not follow one identical path in every dog. The Merck Veterinary Manual describes it in stages that often overlap.

An early, short fever may show up several days after infection, sometimes with low appetite and tiredness. A second fever can come with watery or thick discharge from the eyes and nose, a cough and sometimes pneumonia. Vomiting, diarrhea, poor appetite and dehydration can follow, and bacterial infections on top of the virus can make the breathing or stomach signs worse.

Some dogs develop thickened, hardened nose and paw pads, which is why you may hear the term "hard pad disease." Puppies infected before their adult teeth come in can have damaged teeth.

Nerve signs can appear during the first illness, after a dog seems to be getting better, or sometimes without obvious breathing or stomach signs. They include muscle twitching (often in the face), seizures, jaw-chewing movements, circling, head tilt, poor coordination, weakness, paralysis and behavior changes. UC Davis says neurologic signs develop in up to 30% of affected dogs, a figure from that source, not a prediction for any one dog.

How it differs from parvo and kennel cough. Parvo is a separate puppy emergency centered on vomiting, diarrhea and dehydration; my parvo in puppies guide covers it. Kennel cough is a contagious respiratory illness that is usually a different and milder problem; see kennel cough in dogs. What sets distemper apart is that it can involve the eyes, lungs, stomach and nerves in one dog. Only testing tells these apart, so an unvaccinated dog with a cough and eye discharge still deserves a call to the vet.

Contact a veterinarian promptly for any unvaccinated or incompletely vaccinated dog that has several of these signs, especially a fever along with breathing, stomach or nerve problems. Go the same day, or to an emergency clinic, for any of these, based on guidance from AVMA, Cornell and ASPCApro:

• Trouble breathing.
• Collapse or severe weakness.
• Repeated vomiting or diarrhea, especially with weakness or signs of dehydration.
• Seizures.
• Twitching that keeps getting worse, circling, loss of coordination or paralysis.
• Not being able to eat or drink.
• A puppy whose illness is getting worse fast.
• Any dog that was around a confirmed case and now has signs.

For a dog having a seizure right now, my seizures in dogs page covers what to do in the moment. Either way, call the clinic first and use the words "possible distemper."

Canine distemper is caused by canine distemper virus, a paramyxovirus. According to Merck, the virus first attacks immune-system cells, which can weaken the dog's defenses, and then can reach the lungs, the digestive tract, the skin, the brain and spinal cord, and the optic nerves.

It spreads mainly through airborne droplets from infected animals. Direct contact with an infected dog, or with its saliva, urine, feces and other secretions, can also pass it on. A dog can be contagious before any signs appear, and a dog with mild or no signs can still shed virus. ASPCApro lists a typical incubation period of 1 to 2 weeks, up to 6 weeks.

Wildlife plays a part too. Foxes, wolves, coyotes, raccoons and skunks can be infected, and so can ferrets and other meat-eating animals. That is why a raccoon in your yard at night matters for a puppy that has not finished its shots. People, again, cannot catch it.

Because so many illnesses look alike early on, a veterinarian combines the dog's age, vaccine history, exposure and signs with lab work. Merck and Cornell describe tests that may include:

• RT-PCR or quantitative PCR on swabs, blood, urine, feces or spinal fluid. Cornell calls quantitative PCR the current test of choice.
• Antibody (serology) testing, which can help judge immunity.
• Immunofluorescence or virus isolation in selected cases.
• Blood work, to check immune status and look for secondary infection.
• Chest X-rays when pneumonia or another complication is suspected.

Results need interpreting. A positive PCR finds viral genetic material, so it has to be read alongside vaccine history, timing and signs. An antibody result may reflect a vaccine, not an infection. Ask your veterinarian what a result means for your dog.

Lab fees give a sense of scale, though they are not what an owner pays; dated examples from UC Davis and Cornell's January 2023 fee list are below.

Your bill also includes the exam, sample collection, blood work, imaging, isolation, fluids, nursing care and any hospital stay, and those add up fast. Ask the clinic for an itemized estimate before you agree to a plan.

There is no specific cure that removes the virus. Treatment is supportive care given by veterinary professionals. Merck describes care that can include fluids and electrolytes, nutrition, nursing care, antibiotics for secondary bacterial infection, fever or pain control, and anti-seizure treatment. UC Davis and Cornell describe fluids, nutrition, antibiotics when they are indicated and seizure control in much the same way.

This is hospital-level work guided by exam findings, so there is no home plan to follow and I won't give you doses.

Some dogs do recover, and some do not. Prognosis depends on the dog's immune response, age, how severe the illness is and whether the nervous system is involved. Merck says neurologic disease has an unpredictable outlook and that severe or progressing nerve signs are often hard to treat. Cornell reports that muscle twitching or seizures can remain afterward, and that nerve disease may show up weeks or years later.

The AVMA's 2022 brochure gives a general estimate that about one in two infected dogs die, and that survivors commonly have permanent nervous-system damage. Treat that as a broad 2022 figure, not a forecast for your dog.

A few studies show how hard it is to pin down a treatment:

• A 2016 study of puppies naturally infected with distemper tested porcine antibodies against the virus as an add-on to supportive care and reported better survival than supportive care alone. Merck cites it as Liu et al., 2016, in the Journal of Small Animal Practice. It is an adjunct study, not proof of a general cure.
• A 2016 stem-cell study had only eight dogs, five on supportive care and three on supportive care plus cell therapy. Six dogs died. That is too few dogs to show that the therapy works.
• A 2022 randomized study of 207 naturally infected dogs reported different survival rates with silver nanoparticle treatment. It is not a basis for owner decisions and is not an established cure.

AAHA classes distemper as a core vaccine, recommended for all dogs unless a medical reason changes the plan. Its 2022 guidance starts the puppy series at 6 to 8 weeks, repeats it every 2 to 4 weeks until the puppy is older than 16 weeks, adds a booster within one year after the series, and then boosts the distemper component every 3 years. AAHA notes that finishing at 18 to 20 weeks may be preferred where risk is higher. The WSAVA 2024 guidelines stress finishing the first core series at 16 weeks or older, because antibodies from the mother can block earlier doses.

These are ranges. Your veterinarian adjusts them for age, health, vaccine history, exposure risk, local disease and the product used. Vaccination is the most effective prevention and usually protects dogs, but no vaccine is an absolute guarantee. My new puppy checklist helps you plan shots and first visits, and my page on leptospirosis in dogs covers another infection your vet may bring up at the same appointment.

Until a puppy or unvaccinated dog has veterinary guidance and protection:

• Keep it away from dogs whose vaccine status you don't know.
• Skip dog parks, daycare, boarding, group classes and crowded dog areas.
• Keep it away from raccoons, foxes, skunks and other wildlife.
• Don't share bowls, toys, bedding or grooming tools with unfamiliar dogs.
• If it may have been exposed, call the veterinarian and ask how to handle the exposure and when normal social life is safe again.

There is no single isolation period. Keep a recovered dog away from other dogs and public places until your veterinarian says it is no longer a risk. Cornell reports that shedding commonly lasts about a month, with a range of two weeks to three months, and that some dogs with nerve signs shed for six to eight months. ASPCApro reports shedding for weeks or months after recovery, sometimes up to four months. A 2023 shelter study of 425 dogs found a median of 34 days of detectable viral RNA among dogs with follow-up, and 25% were still testing positive at day 62. Detectable RNA is not the same as live, infectious virus, so ask your veterinarian when the isolation can end and whether follow-up testing makes sense.

For the home, isolate the dog first. Remove dirt and organic material before you disinfect, then clean bowls, crates, floors, bedding and the surfaces you touch most. Use a disinfectant made for enveloped viruses and follow the label. Wash your hands after handling the dog, its waste, its bedding or the cleaning supplies, use separate equipment where you can, and wash or throw away bedding that can't be cleaned. Merck says the virus is sensitive to most disinfectants, including phenolic and quaternary ammonium compounds. Cornell adds that ordinary household disinfectants generally kill it, although cool, dark, damp places can let it last longer. Keep unvaccinated dogs away until your veterinarian confirms the dog and the space are safe.

These answers cover what worried owners ask most.

Fever, tiredness, poor appetite, eye or nose discharge and coughing are common early signs, and vomiting and diarrhea may follow. None of them proves distemper, so an unvaccinated dog with several should be seen promptly after you call ahead.

Some do, particularly with prompt supportive care, but severe cases can be fatal and nerve damage can last. No one percentage fits every dog; AVMA's 2022 brochure gives a general estimate of about one in two infected dogs dying.

No. Canine distemper is not a human infection, according to Cornell's Wildlife Health Lab. Other dogs and some wildlife can catch it, so keep a sick dog away from them.

Vaccination usually protects, and it is the most effective prevention, but no vaccine is an absolute guarantee. A puppy is only as protected as its series is complete, so ask your veterinarian where your puppy stands.

If your dog is sick right now, call your veterinarian or an emergency clinic first, tell them distemper is possible, and keep the dog away from other dogs. If the dog is healthy, the best thing you can do today is check that the vaccine series is complete and on schedule. You can also contact us at DogServ if you can't find what you need. I'm here to help you find the right next step, and your veterinarian makes the call on diagnosis and care.

• American Animal Hospital Association: AAHA
• American Veterinary Medical Association: AVMA's 2022 owner brochure
• ASPCApro: ASPCApro
• Cornell University College of Veterinary Medicine: Cornell's Wildlife Health Lab
• Cornell University College of Veterinary Medicine: Cornell
• Cornell University College of Veterinary Medicine: January 2023 fee list
• mdpi.com: 2022 randomized study
• Merck Veterinary Manual: Merck Veterinary Manual
• PubMed: 2016 stem-cell study
• PubMed Central: 2023 shelter study
• UC Davis School of Veterinary Medicine: UC Davis
• UC Davis School of Veterinary Medicine: UC Davis
• wsava.org: WSAVA 2024 guidelines