How do dogs get kennel cough?

As a dog lover, the idea of your companion returning from a weekend away hacking and miserable is worryingly familiar; kennel cough is one of those problems that can change boarding choices, puppy introductions, and how you manage older dogs at home.

What kennel cough means for your dog and your household

Kennel cough becomes relevant at specific decision points: choosing a kennel or daycare, bringing a new puppy or rescue into a house with other dogs, or deciding whether to let an older dog mingle at dog parks. I typically hear owners weighing the peace of mind of social play against the risk of a contagious cough that could spread through a household.

• Boarding, daycare, and grooming exposure risks are high because many dogs share air, surfaces, and close-contact interactions.
• Introducing a new puppy or rescue is a common moment for outbreaks, since young or stressed dogs may carry pathogens without obvious illness at first.
• Traveling and dog park socialization require a quick risk judgment: is the crowd dense, are dogs coming from far away, and is ventilation poor?
• Homes with older dogs or people who are immunocompromised need extra caution; even a mild respiratory infection in one dog can cascade into more serious problems in vulnerable animals and people.

In one sentence: how dogs actually catch kennel cough

Kennel cough is usually a contagious respiratory syndrome, most often linked to a combination of bacteria and viruses rather than a single organism. It typically shows up as a sudden, harsh cough and can be quite contagious for several days to a few weeks depending on the cause and the individual dog’s immune response.

• What it typically is: a respiratory infection that inflames the throat and airways, often called infectious tracheobronchitis.
• How contagious and how long: many forms spread easily by droplets or close contact and may be most contagious in the first week, though some dogs can shed organisms before symptoms and intermittently afterward.
• Basic first steps: keep the coughing dog away from other dogs, call your veterinarian for advice, and make sure the dog has rest, water, and monitoring of appetite and breathing.
• When to seek immediate care: difficulty breathing, high fever, severe lethargy, or signs that the illness is progressing toward pneumonia.

Meet the microbes — Bordetella, viruses and the infection process

The syndrome we call kennel cough is often the result of multiple pathogens acting together. Bordetella bronchiseptica is a common bacterial contributor, and viruses such as canine parainfluenza and canine adenovirus may also be involved. These agents can act in combination, so a dog may be carrying several at once.

Transmission usually happens through aerosols and droplets produced when an infected dog coughs, sneezes, or barks, and by contact with contaminated surfaces—what veterinarians call fomites—like shared bowls, collars, or bedding. Close face-to-face play or crowded indoor spaces increase the chance a susceptible dog will inhale enough organisms to start an infection.

A quick way to picture what happens inside the dog is to think of irritated airways: the invading organisms attach to the lining of the trachea and bronchi, trigger inflammation, and stimulate the cough reflex as the body tries to clear mucus and debris. That cough is both a symptom and a route for further spread.

The incubation period may be short—often a few days—and contagiousness can begin before signs are obvious. Dogs are often most contagious during early clinical illness, but shedding patterns vary by organism and individual immune response; some dogs may continue to spread bacteria for longer.

When and where kennel cough spikes: locations, seasons and triggers

Places where many dogs gather are the highest risk because density and frequent turnover make exposure both frequent and diverse. Kennels, daycares, shelters, and indoor training or grooming facilities are common sites for transmission—especially if dogs are moving between groups or are confined together.

Ventilation matters: poorly ventilated rooms concentrate airborne droplets and increase risk, while good airflow lowers the chance that a cough from one dog will reach another dog in infectious amounts. Surface contamination also plays a role; shared toys, water bowls, and soft bedding can carry organisms if not cleaned properly.

Stress—whether from travel, recent rehoming, or a busy environment—can weaken a dog’s natural defenses and make infection more likely. Concurrent illnesses, such as a parvovirus recovery or chronic allergies, may also increase susceptibility.

Seasonal factors can influence spread indirectly: colder months often mean more indoor activity and less ventilation, while rainy seasons push social activity indoors. I tend to advise extra caution when lots of dogs are congregating inside during those times.

Symptoms you can’t ignore: red flags that require veterinary care

A single, brief, dry cough in an otherwise bright dog may be a mild case, but watch closely. Persistent or worsening coughing, faster respiratory rate, open-mouthed breathing, or difficulty breathing are urgent signs. If the cough is accompanied by fever, marked lethargy, loss of appetite, or colored nasal discharge, the infection may be progressing or complicated by a secondary bacterial pneumonia.

Puppies, senior dogs, flat-faced breeds, and dogs on medications that suppress the immune system are at higher risk of complications. In these animals a cough that begins as mild can evolve quickly into something more serious. Dehydration and poor intake are common complications when a dog is unwell; if a dog won’t drink or becomes weak, veterinary evaluation is warranted.

Signs pointing toward pneumonia include rapid breathing, shallow breaths, blue-tinged gums, and a cough that produces mucus or blood. These situations need immediate veterinary attention rather than home care alone.

A practical owner’s checklist: immediate steps if your dog shows symptoms

First, separate the coughing dog from other dogs and avoid places where dogs congregate until a veterinarian advises otherwise. Isolation should be practical and humane: a quiet room, fresh water, and a comfortable bed work well. Limit handling to reduce spread and stress.

Call your veterinarian promptly for triage. I usually ask owners for the onset time, cough characteristics, appetite, vaccination history, and any recent exposures like boarding or rescue intake. Depending on the answers, the vet may recommend observation at home, an exam, chest radiographs, or testing for specific pathogens.

Supportive care is the backbone of early management. Encourage rest, keep the dog well-hydrated, and offer palatable food in small amounts if appetite is reduced. A humidifier can sometimes ease throat irritation. Avoid cough suppressants unless a veterinarian prescribes them, since coughing can be protective by clearing secretions.

Keep a simple log: note when the cough began, how often it occurs, whether it’s dry or productive, changes with exercise or excitement, and the dog’s vaccine status. Photos or short videos of the cough can be invaluable to a veterinarian who is triaging remotely. If antibiotics or other medications are prescribed, follow instructions carefully and report any worsening promptly.

Lowering risk: environmental fixes and training adjustments that help

Vaccination is a practical prevention tool but not absolute. Bordetella vaccines—available as intranasal, oral, and injectable formulations—may reduce severity and shedding but may not prevent infection entirely. Intranasal vaccines tend to stimulate local immunity more quickly and may be useful in high-risk settings, while injectable vaccines are often easier to administer and integrate into routine visits. Timing matters: many vaccines take a few days to elicit protection, so vaccinating right before boarding may provide limited benefit.

Cleaning and disinfection reduce surface transmission. Use veterinary-safe disinfectants and follow contact-time directions on labels; repeated cleaning of bowls, bedding, and high-touch surfaces is helpful. Improve ventilation where possible—open windows or use HEPA-filtered air purifiers in indoor play areas—and minimize overcrowding during peak times.

Teach and encourage safe socialization habits: supervised, calm greetings rather than face-to-face sniffing, and gradual introductions if you’re mixing a new dog into a group. For boarding or daycare, ask about vaccination and illness policies, staff training in recognizing respiratory disease, and whether they isolate sick dogs promptly. If a provider lacks clear policies, consider alternatives.

Essential supplies and helpful gear for prevention and care

Select gear that reduces throat strain and contamination. A harness typically avoids pressure on the trachea that a collar can cause, especially in dogs prone to chronic cough or tracheal sensitivity. I often recommend harnesses for small or long-backed breeds that may cough more with collar pressure.

A humidifier or vaporizer in the room where the dog rests can ease throat discomfort and may help thin secretions. Use these safely and according to manufacturer guidance to avoid mold or excessive moisture.

Designate bedding and crates for the isolated dog and keep cleaning supplies—disinfectant wipes, laundry detergent, and disposable gloves—handy. An isolation crate or gate lets you limit contact without confining the dog 24/7; comfort and supervision are important.

Remember that any cough suppressant, antibiotic, or antiviral medication should come from a veterinarian. Over-the-counter human remedies are unsafe for dogs. When medication is prescribed, use only veterinarian-recommended products and complete the full course unless advised otherwise.

Evidence and further reading: the sources behind these recommendations

• Merck Veterinary Manual: Canine Infectious Tracheobronchitis (Kennel Cough) — https://www.merckvetmanual.com/respiratory-system/respiratory-diseases-of-dogs/canine-infectious-tracheobronchitis
• American Veterinary Medical Association (AVMA): Kennel Cough Resources and Guidelines — https://www.avma.org/resources/pet-owners/petcare/kennel-cough
• Cornell University College of Veterinary Medicine: Canine Infectious Respiratory Disease Complex (CIRDC) — https://www.vet.cornell.edu/animal-health-diagnostic-center/learn-more/respiratory-disease
• World Small Animal Veterinary Association (WSAVA) Global Vaccination Guidelines: Canine Vaccination Guidance — https://www.wsava.org/global-guidelines/vaccination-guidelines/