Kennel Cough

In this episode of Current Vet, Dr. Lottie talks about kennel cough, what diagnostics and treatments we should be using (if any?!), which pathogens can be implicated in the condition and when antibiotics may be needed.


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Timeline:
00:00 Intro
00:26 Case
01:42 Aetiology & Pathogenesis
04:23 Clinical Signs
05:40 Diagnosis
08:13 Treatment
11:33 Prevention
13:33 Key Points
14:56 Outro

References

• Reagan, K.L. and Sykes, J.E. (2020) ‘Canine Infectious Respiratory Disease’, The Veterinary Clinics of North America. Small Animal Practice, 50(2), pp. 405–418. Available at: https://doi.org/10.1016/j.cvsm.2019.10.009.
• Priestnall, S.L. et al. (2014) ‘New and Emerging Pathogens in Canine Infectious Respiratory Disease’, Veterinary Pathology, 51(2), pp. 492–504. Available at: https://doi.org/10.1177/0300985813511130.
• Erles, K. et al. (2004) ‘Longitudinal Study of Viruses Associated with Canine Infectious Respiratory Disease’, Journal of Clinical Microbiology, 42(10). Available at: https://doi.org/10.1128/jcm.42.10.4524-4529.2004.
• Lappin, M. r. et al. (2017) ‘Antimicrobial use Guidelines for Treatment of Respiratory Tract Disease in Dogs and Cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases’, Journal of Veterinary Internal Medicine, 31(2), pp. 279–294. Available at: https://doi.org/10.1111/jvim.14627.
• Day, M.J. et al. (2020) ‘Aetiology of Canine Infectious Respiratory Disease Complex and Prevalence of its Pathogens in Europe’, Journal of Comparative Pathology, 176, pp. 86–108. Available at: https://doi.org/10.1016/j.jcpa.2020.02.005.

Current Vet is an educational podcast intended for veterinary students, veterinary professionals, and individuals with an interest in veterinary medicine.

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Any clinical cases discussed in this podcast are fictional, and are designed to reflect typical or likely clinical scenarios for educational purposes. They do not represent specific real-life cases, clients, or animals.

While every effort is made to ensure accuracy and alignment with current evidence at the time of publication, veterinary medicine is a rapidly evolving field, and recommendations may change over time.

Creators and Guests

Host

Dr. Lottie Wilkinson

Creator and host of the Current Vet podcast

What is Current Vet?

The podcast that makes veterinary medicine simple.

In each episode, Dr. Lottie breaks down clinical conditions, cases, and concepts across species, focusing on pathophysiology, decision-making, diagnostics, and what actually matters in practice. It’s the kind of context that makes your knowledge finally click.

Every month, we’ll also have honest conversations with guests about the incredible variety of veterinary medicine, what you can do with a vet degree and how to think bigger about your career.

Whether you’re cramming for exams or looking for a soundtrack for your dog walk, Current Vet will make vet med simple

Intro

Hello, hello, and welcome back to Current Vet, the podcast that makes veterinary medicine simple. I'm your host, Dr. Lottie, and today we are covering one of the most common respiratory conditions you will encounter in small animal practice, and that is kennel cough, or more accurately known as canine infectious respiratory disease complex, or CIRDC.

Case

Let's start with our case. A three-year-old male neutered Labrador called Bailey is presented to your clinic with a cough. His owner tells you he returned from a boarding kennel about five days ago and started coughing two days after coming home. Initially, she thought he had something stuck in his throat because the coughing fits often end with gagging or retching.

He hasn't vomited anything up and is still eating and drinking normally. On exam, Bailey is bright, alert, and wagging his tail throughout the consult. His temperature's normal. His respiratory rate and effort are normal. You notice a harsh, dry cough during the exam, and when you gently palpate his trachea, he immediately starts another coughing episode.

At this point, kennel cough is high on your differential list, but his owner says that he's been vaccinated for kennel cough, so she doesn't think it's that. Another couple of considerations might be tracheal collapse, chronic bronchitis, foreign body inhalation, early pneumonia, or cardiac causes of coughing.

But the combination of the recent boarding, the acute onset cough, and a bright, systemically well dog with a classic hacking cough makes kennel cough the most likely diagnosis

Aetiology & Pathogenesis

Before we go any further, it's so important to understand one of the biggest things about kennel cough, and it is not a single disease, it is a syndrome.

So common pathogens involved include Bordetella bronchiseptica, canine parainfluenza virus, canine adenovirus type 2, canine respiratory coronavirus, Mycoplasma species, canine influenza virus, and canine herpesvirus. And it's very common for dogs to be infected with one or more pathogen at the same time, and that is why we use the term canine infectious res- disease complex.

The term kennel cough comes from the fact that the disease spreads very efficiently in places where dogs are housed very closely together, such as boarding kennels, daycare facilities, shelters, dog shows, training classes, or vet clinics. Basically anywhere that dogs Closely mixed together is a high risk for transmission.

So what's actually happening inside Bailey's respiratory tract? Most kennel cough pathogens infect the epithelial cells lining the upper respiratory tract, particularly in the nasal passages and the trachea and mainstem bronchi. Many of the viruses involved damage this respiratory epithelium and impair the normal defense mechanisms.

So one of the most important defense mechanisms is the mucociliary escalator. In normal, healthy dogs, mucus in this escalator traps inhaled debris and microorganisms, while the cilia move that mucus upwards and out of the respiratory tract. Think of it basically as a self-cleaning conveyor belt in the respiratory tract.

When viruses damage this respiratory epithelium, or when Bordetella produces toxins that impair ciliary function, this clearance mechanism becomes much less effective. Pathogens, debris, and inflammatory material start to accumulate, and the body responds with inflammation. This results in increased mucus production, edema in the airways, recruitment of inflammatory cells, and sensitization of cough receptors.

And that inflammation is what produces that classic harsh, dry cough. The damaged airways are then also more susceptible to secondary bacterial infections, which is why some dogs develop much more severe disease than others and can develop, for example, pneumonia as a complication

Clinical Signs

Bailey is showing the classic presentation of uncomplicated kennel cough. So typical clinical signs are gonna include a dry, harsh cough, coughing triggered by excitement or exercise, gagging or retching after a coughing fit, mild nasal discharge, sneezing, and maybe some mild lethargy. The key thing here is that most dogs remain bright and systemically well.

They typically arrive at the clinic acting completely normal apart from the cough. But not all cases remain uncomplicated. So dogs that develop lower respiratory tract infection secondary to the kennel cough and the damage caused by those initial infecting pathogens can also show pyrexia, marked lethargy, inappetence, tachypnoea, increased respiratory effort, and exercise intolerance.

And if we're seeing these signs, these are the patients we're worrying about pneumonia for. Particularly high-risk groups are going to be puppies, geriatric dogs, any immunocompromised patients, and dogs in crowded shelter environments

Diagnosis

Okay, so we've examined Bailey. We suspect kennel cough. Do we actually need to run diagnostics? In most uncomplicated cases, the answer is probably no. Kennel cough is often a clinical diagnosis, so when a dog presents with that characteristic cough, recent exposure to high-density, highly populated environments, and minimal systemic signs, further testing typically doesn't change our management approach, so it often is just a bit of a waste of time and money for the owners and for you.

So a key thing to think about is, do we actually need to know which pathogen is causing the disease? And in those uncomplicated cases, the answer is typically no. Knowing whether Bailey has parainfluenza or Bordetella or respiratory coronavirus is not gonna change how we're managing the case. But diagnostics do become important when the dog is systemically unwell, if we suspect pneumonia, if we have severe or recurrent clinical signs, if signs persist despite treatment, or we're investigating an outbreak scenario, potentially in a shelter environment.

So our first test that we could do is PCR testing,

It's the most commonly used confirmatory test, and we can do a respiratory PCR panel. So this panel is gonna detect pathogen RNA or DNA

from samples such as oropharyngeal swabs, nasal swabs, or tracheal washes. PCR is highly sensitive and can identify multiple pathogens at the same time. But remember, a positive PCR result doesn't always mean that the pathogen is responsible for causing the disease. A lot of these pathogens can be inhaled from the environment and may be an incidental finding rather than proving that that is actually the cause of this clinical signs.
So a positive PCR doesn't necessarily prove active infection or causation, and that is why PCR results must be interpreted alongside the clinical picture If pneumonia is suspected, thoracic radiographs can also be very useful. Dogs with uncomplicated kennel cough typically have very normal thoracic radiographs, whereas dogs with bronchopneumonia may show interstitial and alveolar lung patterns with that classic cranioventral distribution

Treatment

Let's go back to Bailey. So he's bright, he's eating, he's afebrile, and his respiratory effort is normal. How are we going to treat him? Most dogs like Bailey only need supportive care and not aggressive treatment. So supportive care is going to include good rest, avoiding strenuous exercise, using a harness rather than a neck collar to take pressure off the trachea, maintaining good hydration and balanced nutrition just to support healing, and making sure to avoid any airway irritants like smoke or heavy perfumes in the environment or at home.

Most dogs are typically gonna improve in the next one to three weeks with these measures on their own and the infection self-resolves Antibiotics are not routinely indicated for uncomplicated kennel cough. Most cases are actually viral-caused and they're self-limiting. So using antibiotics in every coughing dog is gonna contribute to antimicrobial resistance, and it typically doesn't have much actual benefit because they're gonna have no effect on viruses.

Antibiotics can be considered if we're suspecting a bacterial infection or pneumonia. If our clinical signs are moderate to severe, we have high-risk patients involved, potentially immunocompromised patients or young puppies, or if the disease is prolonged or worsening despite initial treatment and supportive care.

A culture and sensitivity can be taken before starting empirical antibiotics, and then the choice can be changed based on results if needed.

But as we say, for many straightforward cases, supportive care is entirely appropriate
Antitussives or cough suppressants may occasionally be useful in dogs if they have severe non-productive coughs that affect welfare. So options include hydrocodone or butorphanol. But it's so important to remember that cough suppressants should be avoided if there is a concern for infection. I.e.,

the cough is productive because coughing plays a really important role in clearing respiratory secretions and aiding clearance of infection. So if we're suppressing that cough and the dog has an infection, it can actually cause worsening of the disease. Let's quickly imagine that Bailey returns three days later and he's now pyrexic, lethargic, eating poorly and is breathing faster.

At this stage, we're definitely gonna be concerned about progression to bronchopneumonia and these patients we might consider thoracic radiographs, hematology to check general systemic health, potential airway sampling, systemic antibiotics, hospitalization and potentially oxygen therapy if he's hypoxemic or nebulization and coupage in some cases just to , help to clear those respiratory secretions.

The key clinical skill here is recognizing when a dog has moved from uncomplicated respiratory disease into potential lower respiratory tract infections and knowing the treatment approach in both situations

Prevention

Okay, let's talk prevention. So if we go back to Bailey's case, we remember that The owner said that she doesn't think it's kennel cough because he's vaccinated. So we must understand that while vaccination exists and it helps reduce the severity, the duration, and the shedding of disease, the vaccination does not provide complete protection against infection.

And because kennel cough can be caused by multiple different pathogens, no vaccine can cover every possible cause. This means that while dogs can be vaccinated and they have a lower risk, vaccinated dogs can still develop kennel cough. Typically, they develop milder disease than unvaccinated dogs.

Vaccines are available against several important kennel cough pathogens, so this is going to include Bordetella bronchiseptica, canine parainfluenza virus, and usually those two are found as a combination in an intranasal spray vaccine. And then we also have canine adenovirus type 2.

It is one of the core vaccines as it provides cross-protection against CAV-1, which is canine infectious hepatitis. We actually have an episode on this further back, so If you want to learn more about infectious hepatitis, just go back to that episode. For dogs that regularly board or attend daycare, go to competitions, or frequently mix with other dogs, vaccination may be recommended, but it's not a core vaccine, and it isn't required in all situations.
Other prevention methods are going to include isolating affected dogs from other dogs, making sure that they're avoiding boarding facilities or daycare, especially dog parks and training classes until clinical signs have resolved, and then ensuring good hygiene and cleaning of shared equipment or bedding just to help reduce transmission

Key Points

Okay, if you remember nothing else from today's episodes, make sure you remember these points. Kennel cough is also known as canine infectious respiratory disease complex, and it is a respiratory infection in dogs. It is a syndrome, not a single disease, and multiple different viral and bacterial pathogens may be involved, such as Bordetella bronchiseptica, canine parainfluenza virus, respiratory coronavirus, canine adenovirus 2, and several others.

Most dogs present with a characteristic dry honking cough, but they remain bright and systemically well. Uncomplicated kennel cough is typically a clinical diagnosis and doesn't usually require diagnostic confirmation. Further tests might be indicated, though, if there are worsening or persistent signs, signs of pneumonia, or if there is an outbreak scenario Treatment for uncomplicated cases focuses on supportive care, but if pneumonia or bacterial infection is suspected, antibiotics may be required

Prevention includes isolating infected animals, maintaining good hygiene, disinfecting the environment, and then vaccinations for at-risk dogs.

Outro

And that is canine infectious respiratory disease complex, or just kennel cough. Thank you so much for listening to this episode of Current Vet. If you found it helpful, follow or subscribe wherever you get your podcasts and share it with a friend or colleague who could use a refresher on this topic as well.

And as always, if there's a topic you'd like covered in a future episode, let us know in the comments or find us on Instagram and TikTok at veterinaryvista. We'll see you next time.