Distemper in Dogs: Symptoms, Spread and Prevention

What distemper is and how it spreads

Distemper is caused by canine distemper virus, a relative of the measles virus. The AKC explains that it spreads through direct contact with infected animals or objects, through airborne droplets when infected dogs cough, sneeze or bark, and from a mother to her puppies. Infected dogs can shed virus for several months. Wildlife including raccoons, foxes and skunks also carry it, so a dog that never meets other dogs can still be exposed.

Puppies under about four months old and unvaccinated dogs of any age are most at risk. The AKC lists distemper as a core vaccine alongside parvovirus, canine adenovirus and rabies, and VCA notes that vaccination has made the disease far less common than it once was. It still causes outbreaks where vaccination rates are low, especially in shelters and among stray and rescue dogs.

Symptoms of distemper in dogs

Signs usually come in stages. The first stage looks like a bad respiratory infection: watery then thick yellow discharge from the eyes and nose, fever a few days after infection, coughing, sneezing, low energy and a poor appetite. Vomiting and diarrhea often follow. Secondary bacterial infections can turn this into pneumonia, with fast or labored breathing.

In many dogs the virus then reaches the brain and spinal cord, sometimes weeks later. Nervous system signs include muscle twitching, head tilt, circling, stumbling, weakness or paralysis, and seizures, including the so-called chewing-gum fits where the jaw snaps and chomps. Some dogs develop thickened, cracked pads and nose, the reason distemper is sometimes called hard pad disease. Because these signs overlap with kennel cough, other infections and toxins, testing is needed.

When to call your vet today

Call your vet the same day if a puppy or an unvaccinated or partly vaccinated dog has eye or nose discharge with a fever, cough, low energy or poor appetite, especially if it recently came from a shelter, breeder or rescue, or has been around wildlife. Tell the clinic before you arrive so they can keep your dog away from other patients.

Also call promptly if a dog that recently had a respiratory illness develops twitching, wobbliness or behavior changes, since nervous system signs can appear after the first illness seems to settle.

When it's an emergency

Go to your vet or the nearest emergency vet immediately if your dog has a seizure, especially one lasting more than a few minutes or several in a row, has difficulty breathing, collapses, cannot stand, or is severely dehydrated from vomiting and diarrhea.

During a seizure, keep your hands away from your dog's mouth, move furniture so it cannot hurt itself, and note how long the seizure lasts. Call ahead so the team can prepare an isolation area, because distemper is so contagious.

What you can safely do at home

If distemper is suspected or confirmed, keep the sick dog completely separate from other dogs and from ferrets, which can also catch it. Wash your hands and change clothes after handling it. Keep fresh water available and offer soft, tempting food, and gently wipe discharge from the eyes and nose with a soft, damp cloth.

Do not give human cold or flu medicines, pain relievers or leftover antibiotics; many are toxic to dogs, and none treat the virus. Follow your vet's instructions exactly for any prescribed medicine. Ask your vet when other dogs in the household should be checked and whether their vaccines are current.

Keep a sick or unvaccinated dog away from other dogs; a puppy playpen can help confine a young puppy to one easily cleaned area.

What the vet will likely check

Your vet will look at the pattern of signs, vaccination history and possible exposure. The AKC notes that diagnosis uses clinical signs together with a PCR test to detect the virus or antibody testing, with blood work and chest X-rays to look for secondary infections such as pneumonia. Diagnosis can be tricky early on because the first signs look like many other illnesses.

There is no antiviral cure. Treatment is supportive and usually takes place in an isolation ward: fluids for dehydration, medicine to control vomiting, diarrhea and seizures, antibiotics for secondary bacterial infections, and nursing care. VCA describes distemper as often fatal, and dogs that survive may be left with lasting muscle twitches or recurring seizures, which is why prevention matters so much.

Prevention and vaccination

Vaccination is the best protection. VCA states that puppies receive distemper vaccines at 8, 12 and 16 weeks of age, followed by boosters every one or three years depending on the vaccine used, and the AKC stresses finishing the full puppy series and keeping boosters current without gaps. Your vet will set the exact schedule for your dog, usually as part of a combination vaccine.

Until a puppy has finished its series, avoid dog parks, pet store floors and places where unknown dogs gather, and choose classes that check vaccination records. Keep dogs away from wildlife, secure trash and pet food outdoors, and vaccinate pet ferrets as their vet advises.

This page is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your pet.