It depends on the type. Acute infectious bronchitis, commonly called kennel cough, is highly contagious and spreads rapidly between dogs. Chronic bronchitis, which tends to develop in middle-aged and older dogs, is not contagious at all. If your dog has a new cough and was recently around other dogs, you’re most likely dealing with the contagious kind.
Acute vs. Chronic: Two Different Conditions
The word “bronchitis” simply means inflammation in the airways, and in dogs it covers two very different situations. Acute infectious bronchitis (kennel cough) is caused by viruses and bacteria that pass from dog to dog. It typically resolves on its own within 10 to 20 days, with the worst coughing fading in the first five days. Most affected dogs show few other symptoms beyond a harsh, dry cough, occasional retching, and some loss of appetite.
Chronic bronchitis is a long-term condition defined by a persistent cough lasting at least two months that isn’t caused by another respiratory disease. It most often shows up in small and middle-aged to older dogs, and it tends to flare with weather changes, environmental stress, or the start of exercise. Because it’s driven by ongoing airway irritation rather than infection, it poses zero risk to other dogs in your household or at the park.
How Kennel Cough Spreads
Infectious bronchitis spreads through airborne droplets produced when a sick dog coughs, sneezes, or pants. It also passes through direct nose-to-nose contact and through shared surfaces like water bowls, toys, and kennel floors. The disease moves fastest in close-confinement settings: boarding kennels, doggy daycares, veterinary hospitals, and shelters.
What makes kennel cough especially tricky is that most dogs are contagious before they start showing symptoms. By the time you notice the cough, your dog may have already been shedding the pathogen for days. The illness itself is usually mild, with full recovery in 7 to 10 days, but during that entire stretch your dog can still pass it along.
The Pathogens Behind It
Kennel cough isn’t caused by a single germ. It’s a complex involving multiple viruses and bacteria that can act alone or together. The traditional culprits include the bacterium Bordetella bronchiseptica, canine parainfluenza virus, canine adenovirus type 2, canine distemper virus, and canine herpesvirus. More recently, canine influenza virus, canine respiratory coronavirus, and several other bacterial species have been identified as contributors. A dog may pick up one pathogen or several at once, which is why the severity of illness can vary so much from case to case.
Can It Spread to Humans or Cats?
In rare cases, Bordetella bronchiseptica (the most common bacterial player in kennel cough) can infect humans. Documented cases are uncommon and almost exclusively involve people with weakened immune systems. One notable report described a woman who developed a Bordetella infection from her dog after the dog received a live intranasal vaccine, since vaccinated dogs can shed the bacteria for weeks afterward. For a healthy adult, the risk is extremely low. If anyone in your household is immunocompromised, it’s worth mentioning your dog’s illness or recent vaccination to their physician.
Keeping Other Dogs Safe
If your dog is coughing and you suspect kennel cough, isolation is the single most important step. Keep your dog away from all other dogs until the cough is completely gone, not just improving. That means skipping the dog park, canceling daycare, and avoiding shared walking areas when possible. In a multi-dog household, separate the sick dog into a different room and don’t share water bowls, bedding, or toys between them. Clean shared surfaces with a standard disinfectant.
Shelters and boarding facilities typically follow strict protocols: new dogs entering the facility go through an isolation period, staff monitor the group daily for coughing, and any dog that develops symptoms gets quarantined immediately. If you’re boarding your dog or enrolling in daycare, asking about their respiratory disease protocol is reasonable.
Vaccination Options
Vaccines exist for the two most common kennel cough pathogens: Bordetella bronchiseptica and canine parainfluenza virus. For pet dogs living in homes, these are considered non-core vaccines, meaning they’re recommended based on lifestyle risk rather than given to every dog. Dogs that regularly visit boarding facilities, daycares, groomers, or dog parks are the strongest candidates. For shelter dogs, these same vaccines are considered essential because the exposure risk is so high.
Bordetella vaccines come in three forms: intranasal (sprayed into the nose), oral, and injectable. The intranasal and oral versions provide protection after a single dose and can be given to puppies as young as three weeks old, depending on the product. Injectable versions require two doses spaced two to four weeks apart. All types need annual boosters. One important caveat: these vaccines reduce the severity of illness but don’t guarantee your dog won’t get infected. Think of them the way you’d think of a flu shot, helpful but not a forcefield.
How to Tell Which Type Your Dog Has
The clues are often straightforward. A previously healthy dog that develops a sudden, harsh, honking cough after a stay at a kennel, a visit to the groomer, or time at the dog park almost certainly has infectious bronchitis. The cough often sounds like the dog has something stuck in its throat, and it may end with gagging or retching up white foam.
Chronic bronchitis looks different. The cough has been present for months, tends to be worst after resting or at the start of a walk, and the dog is typically middle-aged or older. There’s no recent history of exposure to a group of dogs. The cough is the body’s attempt to clear mucus that accumulates in irritated airways, so it often sounds wet rather than dry. Your vet can distinguish between the two based on history, symptoms, and if needed, imaging or airway sampling to rule out other causes like foreign bodies, fungal infections, or structural problems in the lungs.