Kennel cough is a highly contagious respiratory infection in dogs that causes a sudden, persistent, honking cough. Most cases are mild, and dogs fully recover within 7 to 10 days. Veterinarians formally call it canine infectious respiratory disease complex (CIRDC) because multiple bacteria and viruses can cause it, often at the same time.
What Causes Kennel Cough
Kennel cough isn’t a single infection. It’s caused by a mix of bacteria and viruses that attack the lining of a dog’s upper airways. The most common bacterial culprit is Bordetella bronchiseptica, which is why you’ll sometimes hear “Bordetella” used interchangeably with kennel cough. Canine parainfluenza virus is another frequent contributor. In many cases, a virus weakens the airway lining first, then bacteria move in and make symptoms worse.
Several organisms can be involved at once, and the specific combination affects how sick a dog gets. A dog exposed to just one mild virus might barely show symptoms, while one dealing with both a virus and Bordetella could develop a more persistent cough.
How It Spreads
Dogs catch kennel cough in three main ways: breathing in airborne droplets from a coughing dog, direct nose-to-nose contact with an infected dog, or touching contaminated surfaces like shared water bowls, toys, or kennel floors. This is why the infection tears through boarding facilities, dog parks, grooming salons, and shelters so efficiently.
Bordetella bacteria survive only a few hours in respiratory secretions on most surfaces, but they’re hardier than you might expect in other environments. They can persist in soil for up to 45 days and in standing water for weeks. Still, the primary risk is close contact with other dogs, especially indoors or in enclosed spaces where airborne droplets concentrate.
The incubation period ranges from 2 to 14 days, meaning your dog could pick up the infection at a kennel and seem perfectly fine for nearly two weeks before symptoms appear.
What Kennel Cough Sounds Like
The hallmark symptom is a sudden, forceful, honking cough that can sound alarming. Many owners describe it as gagging or retching, and dogs sometimes bring up white froth that looks like vomit. This cough often comes in fits and can be triggered by excitement, pulling on a leash, or drinking water.
Beyond the cough, you may notice sneezing, a runny nose, or watery eyes. In mild cases, that’s the extent of it. Your dog’s energy and appetite stay normal, and the cough is mostly an annoyance rather than a sign of serious illness. Dogs are typically sick for one to two weeks.
When Kennel Cough Becomes Serious
Most dogs handle kennel cough without complications, but some cases progress. Warning signs include lethargy, loss of appetite, fever, labored or rapid breathing, and a cough that shifts from dry and honking to wet and productive. These can signal that the infection has moved deeper into the lungs and developed into pneumonia.
Puppies, senior dogs, and dogs with weakened immune systems are at higher risk for complications. There have also been reports of an atypical form of kennel cough where dogs cough for 6 to 8 weeks or develop pneumonia more readily. In these atypical cases, standard lab tests for common respiratory pathogens sometimes come back negative, suggesting less familiar organisms may be involved.
If your dog becomes lethargic, stops eating, or shows any signs of breathing difficulty, that warrants a veterinary visit rather than continued home monitoring.
Treatment
Mild kennel cough usually resolves on its own with supportive care at home. Your vet may prescribe antibiotics if they suspect a bacterial component, particularly Bordetella, or if your dog seems at risk for a secondary infection. For dogs with a persistent, disruptive cough, prescription cough suppressants can provide relief. However, cough suppressants are never used when pneumonia is present, because coughing helps clear infected material from the lungs.
At home, a few simple steps can make your dog more comfortable during recovery:
- Switch to a harness. A collar puts pressure on the windpipe and can trigger coughing fits. A harness distributes the force across the chest instead.
- Use a humidifier. Adding moisture to the air helps soothe irritated airways, similar to what you’d do for a human with a bad cold.
- Limit exercise and excitement. Activity and heavy panting can aggravate the cough, so keep walks short and calm.
Keeping Other Dogs Safe
Kennel cough is extremely contagious. If your dog is diagnosed or showing symptoms, isolate them from other dogs immediately. This means no dog parks, no daycare, no walks where they’ll encounter other dogs, and no shared toys or bowls with dogs in your household.
Dogs can continue shedding the infection even after symptoms improve, so plan on keeping your dog separated from others for at least a week after the cough has fully resolved. If you have multiple dogs at home and one gets sick, there’s a good chance the others have already been exposed by the time you notice symptoms.
Vaccination
A vaccine against Bordetella bronchiseptica is available and commonly required by boarding facilities, doggy daycares, and grooming salons. It comes in three forms: intranasal (squirted into the nose), oral (given by mouth), or injectable. The mucosal versions (nasal and oral) require only one dose, even for puppies and previously unvaccinated dogs. The injectable version typically requires two initial doses.
Most boarding kennels require the vaccine to have been given within six months of the stay, and it should be administered at least one week before boarding to give your dog’s immune system time to respond. UC Davis School of Veterinary Medicine recommends annual mucosal vaccination for dogs that will be boarded, shown, or exposed to kennel environments.
One important caveat: respiratory vaccines like the Bordetella vaccine are generally less effective than core vaccines like rabies or distemper. Vaccination reduces the severity of illness and lowers the chance of infection, but it doesn’t guarantee complete protection. Multiple organisms cause kennel cough, and the vaccine only targets one or two of them. A vaccinated dog can still get sick, though the illness tends to be milder and shorter.