Distemper in raccoons is a viral infection caused by canine distemper virus (CDV), a relative of the human measles virus. It attacks a raccoon’s respiratory system, digestive tract, and brain in stages, producing increasingly severe symptoms that often end in death. It’s one of the most common diseases in wild raccoon populations across North America, and it’s the likely explanation when you see a raccoon wandering in daylight, stumbling, or acting confused.
How the Virus Spreads
Canine distemper virus spreads through direct contact with an infected animal’s bodily fluids: nasal discharge, saliva, urine, and feces. Raccoons typically pick it up by encountering sick animals or contaminated den sites. The virus first takes hold in lymph tissue in the upper respiratory tract and tonsils, then suppresses the immune system, allowing it to spread deeper into the body over the following days.
Outbreaks tend to peak during breeding season, when raccoons are in closer contact with each other. A single sick raccoon in a neighborhood can seed an outbreak that moves through the local population over weeks or months. While distemper causes high mortality in raccoons, seroprevalence studies show it can also circulate widely with many survivors, meaning some raccoons fight it off and develop immunity.
Symptoms and How They Progress
Signs of distemper typically appear 10 to 14 days after infection. The disease moves through distinct phases, each more serious than the last.
Early symptoms look like a bad respiratory illness: watery discharge from the eyes and nose, fever, coughing, lethargy, and loss of appetite. Because the virus suppresses the immune system, secondary bacterial infections often pile on, turning that watery discharge thick and yellowish-green. Some raccoons develop bacterial pneumonia at this stage, with labored breathing and a wet, productive cough.
The gastrointestinal phase brings vomiting and diarrhea, sometimes with blood. The virus erodes the lining of the digestive tract, leading to dehydration and dangerous electrolyte imbalances. The skin on the nose and footpads may thicken and crack, a condition called hyperkeratosis. This is distinctive enough that distemper was historically nicknamed “hard pad disease.”
The neurological phase is the one that gets people’s attention. About 8 to 9 days after infection, the virus reaches the central nervous system and begins causing brain inflammation. Raccoons develop:
- Circling behavior and head tilts
- Muscle twitches and tremors
- Seizures
- “Chewing gum fits” where the jaw snaps and spasms uncontrollably, with heavy drooling that progresses into full seizures
- Aimless wandering, fearlessness around people, and sometimes aggression
This is the stage that produces the “zombie raccoon” reports that occasionally make local news. A raccoon walking in circles in a parking lot at noon, seemingly unaware of people or cars around it, is almost certainly in the neurological phase of distemper. Once a raccoon reaches this stage, recovery is extremely unlikely.
Distemper vs. Rabies
The behavioral symptoms of late-stage distemper, particularly the fearlessness, aggression, and disorientation, look very similar to rabies. Cornell University’s Animal Health Diagnostic Center notes that distemper and rabies infections can be indistinguishable in wildlife based on symptoms alone, and testing for both diseases should be considered. You cannot tell the difference just by watching the animal.
This matters because rabies is fatal to humans. Any raccoon acting disoriented, aggressive, or unusually tame should be treated as potentially rabid until proven otherwise. The practical response is the same regardless of which disease is responsible: stay away from the animal and keep pets and children clear.
Risk to Dogs and Other Pets
Canine distemper virus doesn’t just affect raccoons. It infects dogs, foxes, skunks, ferrets, and many other mammals. When distemper is circulating in your local raccoon population, your dogs face elevated risk, especially if they spend time outdoors unsupervised.
Puppies younger than four months and unvaccinated dogs are most vulnerable. The canine distemper vaccine, included in the standard combination vaccine your vet gives (sometimes labeled DAPP or DA2PP), is considered a core vaccine recommended for all dogs. A properly vaccinated dog has strong protection. The concern runs both directions: unvaccinated dogs can also serve as a source of infection for wildlife.
Cats are not susceptible to canine distemper virus. (Feline distemper is a completely different disease caused by a different virus.)
Risk to Humans
Canine distemper has historically been considered a non-human disease, and no confirmed human infections from raccoons have been documented. However, researchers have raised concerns in recent years. The virus has expanded its host range to include primates, and lab studies have shown that certain adapted strains can use human cell receptors for entry. Scientists have proposed that species jumps to humans could theoretically occur, particularly in people who lack cross-protective immunity from measles vaccination. For now, the practical risk remains theoretical, but it’s another reason to avoid handling sick wildlife.
What To Do if You See a Sick Raccoon
Do not approach, touch, or attempt to help a raccoon showing distemper symptoms. Even well-intentioned contact puts you at risk for bites or scratches, and you can’t rule out rabies from observation alone. Keep pets and children away from the animal.
If the raccoon is posing a direct threat to people or pets, call your state wildlife agency’s emergency line or local animal control. Many counties have animal services departments that respond to reports of sick raccoons. You can also contact a licensed wildlife rehabilitator, though most will not attempt to treat raccoons in the neurological phase of distemper.
If you or a pet were bitten or scratched by a raccoon showing these symptoms, seek medical or veterinary care immediately and contact your local county health department. Rabies post-exposure treatment is time-sensitive.
If you find a dead raccoon on your property, avoid touching the carcass with bare hands. Use a shovel to pick it up and either bury it or double-bag it in garbage bags for disposal in household trash. Disinfect the shovel with a 10% bleach solution and wash your hands thoroughly.