Kennel cough in dogs: symptoms, infection and treatment

Overview

Kennel cough is not the name of a single microorganism. It is a group of respiratory diseases in which the trachea and bronchi can become inflamed. Bordetella bronchiseptica is one possible bacterium, while parainfluenza virus and adenovirus, for example, can also contribute. A dog can have more than one causative organism at the same time.

Despite its name, the disease can spread outside kennels. Dog parks, boarding facilities, shows and training groups bring dogs close together. With mild disease, a dog may seem quite well between coughing bouts.

The group of diseases is also called CIRDC, short for canine infectious respiratory disease complex. Viruses are considered the main cause in most cases.

Other possible viral causes include canine influenza virus and, less commonly, canine distemper virus. Respiratory coronaviruses and pneumovirus can also contribute to the same disease complex.

Causes

Microorganisms in respiratory secretions spread from dog to dog. Bordetella can spread through droplets produced by coughing and sneezing, direct contact and contaminated objects. Shared water bowls, toys and human hands can therefore play a part in transmission.

The bacterium can attach to and damage the airway lining. Damage caused by a virus can, in turn, make secondary bacterial infection easier.

Crowded conditions and an unfavourable environment can increase susceptibility and worsen disease. Stress and extremes of ventilation, temperature and humidity, for example, contribute to risk.

The characteristic cough begins about 5–10 days after contact with affected or susceptible dogs. Bordetella's incubation period averages about 6 days, with a range of 2–10 days.

Mycoplasmas and Streptococcus equi subspecies zooepidemicus are other possible bacterial causes.

Risk factors

Dogs of any age can become ill, but puppies have a higher risk of severe disease. Dogs at risk of Bordetella infection also include unvaccinated dogs and those with existing respiratory disease or another illness that weakens immunity.

Risk increases when dogs are kept close together or meet in large groups. Day care, boarding stays and shared activities are therefore useful details when discussing possible exposure.

Bordetella can act as a primary pathogen, particularly in puppies younger than 6 months. Concurrent viral or bacterial infection can make signs worse.

Infection can also spread from a dog without signs, as pathogens may be present without visible illness.

Typical symptoms

The typical cough is harsh and dry, sometimes resembling a horn or a goose honking. Afterwards, your dog may gag or retch, which can look as though something is stuck in the throat. Exercise can worsen the cough.

• Sudden, repeated coughing bouts.

• Retching or gagging after coughing.

• Sneezing and nasal discharge.

• Discharge from the eyes.

• Tiredness or reduced appetite.

Mucus may come from the mouth after coughing. This can look like vomiting, so explain as precisely as possible whether a coughing bout comes before the discharge appears.

Fever, marked dullness, pus-like nasal discharge and a mucus-producing cough can be associated with pneumonia.

Cough severity usually begins to decrease within the first 5 days, although it has not yet stopped. Light contact with the trachea or larynx can trigger coughing.

Complications and consequences

Pneumonia is the main concern, particularly in puppies and other vulnerable dogs. In a debilitated adult or an older dog, the disease may also be associated with prolonged bronchitis.

An uncomplicated infection usually resolves on its own within 7–14 days. Kennel cough can also last 10–20 days overall. In an otherwise healthy dog, recovery from mild Bordetella infection often takes 7–10 days. The end of coughing and the end of infectiousness are different things.

Bordetella can also infect cats and some other mammals. Human illness is rare and usually associated with weakened immunity.

Diagnosis at the vet

The vet assesses the cough's character, breathing, general condition and possible exposures. Vaccination records are also useful. A typical history and mild signs often allow a clinical assessment without identifying every causative organism.

If your dog is unwell, coughing persists or pneumonia is suspected, X-rays help assess the lungs. Chest X-rays can be normal in a dog whose only sign is coughing. Pneumonia may cause changes in the lung's air-sac regions.

Blood tests and respiratory samples for PCR testing or bacterial culture are taken when needed. PCR detects a pathogen's genetic material.

A PCR sample may be taken from the nasopharynx or tracheal region using a method chosen by the vet.

Other causes of coughing must be considered even with a compatible exposure history. Airway irritation after a breathing tube used during anaesthesia, for example, can resemble infectious tracheitis.

A positive PCR result does not always mean the organism found is causing the current signs. A strain from a live vaccine may also appear in the test. Conversely, a sample taken late may be negative because virus shedding is greatest early in the disease.

When investigating an outbreak affecting several dogs, samples may be taken from several affected dogs. Cytology of nasal discharge alone has limited value for assessing bacterial infection and choosing an antibiotic.

Repeat bacterial culture is not usually needed after successful treatment.

Treatment

The vet prescribes treatment according to disease severity. An otherwise well dog often recovers with rest, monitoring and other supportive care. Antibiotics are not an automatic treatment for every case of kennel cough. They are generally unnecessary in uncomplicated disease, while pneumonia or a significant bacterial infection may change the situation.

A cough suppressant may be considered for a suitable patient, but is unsuitable for pneumonia or a cough producing substantial mucus. Do not give human cough medicines on your own initiative.

Severe disease may require hospital care, fluids, nebulisation and oxygen. If an antibiotic is needed, bacterial culture and susceptibility testing can guide the choice.

At home, take a break from dog groups and avoid exertion that worsens coughing. Monitor eating, alertness, breathing at rest and any change in the cough. Call again if a dog receiving home care becomes clearly more unwell.

The environment and nutrition also matter during recovery. A stressful environment and inadequate nutrition can contribute to signs returning. Provide a quiet resting place and report any difficulty eating.

Pus-like nasal discharge does not automatically mean an otherwise well dog needs antibiotics. Fever, tiredness or refusal to eat alongside this discharge increases the need to consider antibacterial treatment. If the chosen antibiotic has not helped within 7 days, further investigation is needed before switching antibiotic groups.

A dog with coughing alone often does not need hospitalisation. If hospital care is necessary, the dog is kept apart from other animals to reduce transmission.

Doxycycline is a possible first-choice antibiotic for bacterial kennel cough requiring treatment without pneumonia. Not all Bordetella strains and mycoplasmas are susceptible to the same antibiotics.

Prevention

Vaccines reduce the risk of illness and severe signs, but do not guarantee complete protection against every respiratory infection. Bordetella vaccination is considered according to exposure risk. Some breed clubs recommend annual kennel cough boosters for dogs taking part in organised activities or competitions. Agree your dog's vaccine choice and timing with your vet before boarding or an event.

Wash your hands after handling a sick dog and keep their bowls and toys separate. Avoid contact with other dogs during illness and follow the veterinary team's isolation instructions. Some dog events require at least 2 weeks without signs before returning; the restriction also covers symptom-free dogs in the same household. This rule does not mean infectiousness has definitely ended for every possible causative organism.

Bordetella survives in the environment for at least 10 days. Infection can also spread through contaminated water, so a sick dog should not use shared water bowls.

Bordetella vaccination can begin as early as 6–8 weeks, depending on the product and exposure risk. Vaccination age is chosen according to the product's instructions. Read more in the dog vaccination guide.

Bordetella vaccines include options given by mouth, into the nose or under the skin. A vaccinated dog may have milder signs and shed fewer bacteria than an unvaccinated dog.

If an owner has weakened immunity, the route of the dog's Bordetella vaccination is assessed separately. An injectable option may then be more suitable than a live vaccine given into the nose or mouth.

In situations with particularly high exposure risk, a Bordetella booster may also be considered every 6 months following veterinary assessment.

Important for dog owners

Also agree what to do if another dog in the household starts coughing. Record when coughing began, contacts with other dogs and changes in general condition. Take a video of the cough if you can do so safely. Tell the practice about suspected infection before arrival and ask where to wait. Arrange care for the family's other dogs so they do not attend group activities alongside the affected dog.

A dog infected with Bordetella can remain contagious for 8 weeks or longer after signs have ended. Agree a return to contact separately, particularly when your dog meets puppies or other dogs at risk. Consider the treating vet's assessment as well as an event's minimum rule.

Frequently asked questions

Can a vaccinated dog get kennel cough?

Yes. Vaccination can reduce the risk and severity of signs and the shedding of microorganisms, but does not provide complete protection against every possible cause. A vaccinated dog with a cough should therefore also stay away from dog groups and have their condition monitored.

Does kennel cough always need antibiotics?

Not usually in mild, uncomplicated disease. Rest and supportive care are enough for many dogs, but pneumonia or a more serious bacterial infection may require medication. The vet assesses the need from signs and test results; do not start a previous antibiotic yourself.

When does a coughing dog need urgent treatment?

Breathing difficulty, marked tiredness, refusal to eat and fever make the situation more urgent. A decline in a puppy's condition deserves particular attention. Call the practice and describe signs and exposures so the team can advise on examination and safe arrival.

Can a symptom-free dog from the same household attend an event?

Some event rules also restrict symptom-free dogs from a household with a contagious respiratory disease. Check the current policy for your event and follow the veterinary team's advice. Having no signs does not, by itself, make another dog's exposure history irrelevant to preventing infection.

Is a dog no longer infectious as soon as coughing stops?

Not necessarily. Bordetella may still be shed for 8 weeks or longer after signs resolve. Returning to groups therefore depends on the suspected organism, your dog's circumstances and the event's rules. Ask your vet for isolation advice suited to your situation instead of using only the last day of coughing as the cut-off.