Kennel Cough in Dogs: Symptoms, Treatments, Vaccine

Kennel cough in dogs is an upper respiratory tract infection. It's commonly associated with either a Bordetella bronchiseptica or canine parainfluenza virus (CPIV) infection; these are the components of what most people consider the kennel cough vaccine. However, there are many other infectious causes of a dry, hacking cough in dogs. In fact, in different geographic locations, some of the other causes are a lot more common than Bordetella or parainfluenza.

The name "kennel cough" comes from the fact that the infections can spread in kennels. However, dogs can pick up an infectious cough just about anywhere they come in contact with other dogs — in animal shelters (especially ones with poor ventilation) and veterinary hospitals and at dog shows, dog parks, and grooming salons. The more accepted name in the veterinary community is now canine infectious respiratory disease (CIRD).

Causes of upper respiratory tract infections in dogs

In addition to Bordetella and parainfluenza, causes of an infectious cough in dogs include canine distemper virus, canine adenovirus type 2, canine influenza, canine pneumovirus, canine respiratory coronavirus, canine herpesvirus, pantropic canine coronavirus, canine reovirus, mycoplasma, and Streptococcus equi subspecies zooepidemicus. The last two, along with Bordetella, are bacteria. The others are viruses.

Any dog exposed to one of these pathogens can be infected. However, a dog is much more likely to be infected in a moist, warm environment with poor ventilation and with repeated exposure, such as in a kennel or a shelter. It is common for shelters to have to quarantine a whole section once an infectious cough breaks out because it spreads so easily and quickly. Yet even a simple exposure that occurs during a quick meeting at a dog park is enough to transmit the infection.

Kennel cough symptoms

So how can you tell if your dog has kennel cough? Once a dog is exposed, it usually takes two or three days before the dog starts to show symptoms, but it can be up to 10 days. The one exception to this is canine distemper. With distemper, it can take up to four weeks before signs are noted. 

The most common kennel cough symptoms are typically mild and include a cough (especially when pressure is applied to the trachea or windpipe), sneezing, and eye discharge. The cough can often sound like the dog is retching, or it could be described as dry and hacking.

In more severe infections, the dog can have a fever and might have trouble breathing. The dog won't be interested in eating and will appear to be very tired. The more severe kennel cough symptoms tend to occur in unvaccinated dogs; dogs with weak immune systems, such as puppies; or dogs with other illnesses. 

Canine infectious respiratory disease diagnosis

Most veterinarians can diagnose canine infectious respiratory disease (CIRD) based on clinical signs alone. However, they might take chest X-rays to make sure that pneumonia is not present, as this would change the treatment.

It is possible to figure out what the underlying cause is, but it’s often not necessary (or worth the expense) for an individual animal — unless the dog doesn't respond to initial therapy, if there are signs of more aggressive disease, if multiple dogs are coming down with the same signs at the same time, or if there's an outbreak in a shelter or kennel. In the case of a shelter or kennel outbreak, it's important to know the underlying cause because it will dictate which cleaning agents are necessary, how long quarantine should be, and whether vaccine recommendations should be changed for that organization.

To figure out what the underlying cause is, a culture can be taken of the dog's upper airway. However, this typically requires sedation and only covers bacteria; it won't diagnose viruses. 

Recently, it has been more customary to do a swab of the dog's nose and deep throat and send out for polymerase chain reaction (PCR) tests to look for genetic material of the underlying cause. These tests can test for everything, they don't require sedation, and they are relatively affordable compared to doing other tests for each individual organism.

Kennel cough treatments

In many situations, cases of CIRD will resolve on their own without treatment (similar to the common cold in humans), but the traditional kennel cough treatment is antibiotics. Ideally, the antibiotic chosen is based on culture results. But often an antibiotic such as doxycycline is chosen, as it takes care of the more common bacterial causes of CIRD. 

There is controversy about when and whether to start antibiotics because most of the causes of CIRD are viruses, and therefore antibiotics do not directly treat them. However, it's not uncommon for secondary bacterial infections to occur, especially in puppies and dogs with weak immune systems. Antibiotics can prevent progression to more serious disease.

Most veterinarians will start antibiotics if the dog has a fever, the dog is very lethargic, there is yellow or green discharge, the dog isn't eating, or the cough is getting worse instead of better after a few days. Antibiotics are also started if a culture dictates that treatment or if the PCR test reveals a more aggressive bacterial infection, such as streptococcus. Streptococcus has a greater likelihood of making a dog very sick and can even result in death. Antibiotics can also shorten the shedding period (the time a dog is contagious to other dogs), so they are often considered in cases in the shelter environment to control the spread to the rest of the population.

If the cough is severe enough, a cough suppressant might be prescribed. These medications can make an animal more comfortable, but they also can make it harder for the dog to clear the infection. Coughing is a way to expel mucous and infectious agents, so decreasing the cough can be counterproductive.

There is no easy home remedy for kennel cough other than time. Most dogs will clear the infection themselves in 10 to 14 days (with the exception of distemper, which can take weeks or months to clear). As long as the dog is acting fine otherwise and the cough is not worsening, you could wait before doing any treatment. We still recommend taking the dog to a veterinarian, however, to make sure no other interventions are needed first. It can be helpful to nebulize the dog with some sterile saline. A nebulizer can be used for about 10 minutes twice a day to help keep the dog’s airway moist.

Most dogs are not contagious after 10 to 14 days of being ill, especially if antibiotics are used in bacterial infections (with an exception being canine distemper virus). So it's important to keep a coughing dog away from other dogs for at least 10 to 14 days.

Prognosis for kennel cough in dogs

For most cases of kennel cough in dogs, the prognosis is very good. Most dogs don't even require treatment and recover on their own within 10 days. If pneumonia is present, much more aggressive therapy is required, but dogs typically recover if this therapy is administered.

A poorer prognosis occurs with dogs who have concurrent respiratory disease, such as a collapsing trachea or upper airway constrictions. Also, brachycephalic dog breeds (short-nosed dogs such as pugs, bulldogs, and Boston terriers) with CIRD need to be treated more aggressively because their compromised airway makes them more prone to getting secondary bacterial infections, and they have a harder time clearing the infection.

Dogs with weak immune systems also have a more guarded prognosis. Puppies, dogs with immune-mediated disease, dogs on immunosuppressive drugs such as prednisone, and dogs with cancer are all more likely to require more intensive therapy and have a poorer prognosis.

Furthermore, even though the signs of kennel cough in dogs are very similar regardless of the infectious agent involved, the infectious agent can have a significant impact on prognosis. For instance, untreated dogs with Streptococcus equi subspecies zooepidemicus can die.

Dogs vaccinated for the CIRD pathogens have a much better prognosis. Vaccination does not completely prevent infection in most cases, but it can dramatically reduce the duration and severity of disease.

Kennel cough vaccines

The easiest form of prevention is vaccination. Vaccines are available for canine distemper, canine parainfluenza virus, canine adenovirus type 2, canine influenza virus, and Bordetella. Of these, the distemper, parainfluenza, and adenovirus vaccines are part of the core vaccines that most veterinarians administer. The Bordetella vaccine is typically reserved for dogs at significant risk, such as those who frequent kennels, doggy daycare, and grooming salons. The canine influenza vaccine is typically done only in areas where there have been significant outbreaks or for dogs who travel a lot and might go to an outbreak area.

It is important to remember that the vaccines don't prevent infection or prevent a dog from spreading one of the pathogens. However, vaccines do decrease the duration and severity of illness. The one exception is the canine distemper vaccine, which does actually help prevent a dog from being infected. Because of this, along with the negative characteristics of canine distemper (taking longer to show signs, being shed for a longer period, the possibility of long-term problems, and even death), many veterinarians recommend that dogs be vaccinated for distemper at an early age and be given boosters throughout their lives.

The fact that most vaccines don't prevent infection is part of the answer to why a dog might still get kennel cough even though that dog has been vaccinated with the kennel cough vaccine. Another part of the answer is the fact that of the 11 common pathogens that cause CIRD, there are vaccines for only five of them. When outbreaks of coughing happen at a kennel, the culprit is usually one of the five that cannot be vaccinated for.

Vaccines also don't take effect immediately; it takes time for the dog’s immune system to respond to the vaccine and develop protection. Depending on the pathogen and the vaccine type, this process can take two weeks or longer.

It is also important to remember that puppies aren’t considered fully vaccinated until they are at least 4 to 5 months old. When puppies are born, they acquire some protection from infectious disease from their mother through maternal antibodies. Over time, maternal antibodies decrease, though the rate is different for each individual.

Maternal antibodies also can interfere with vaccine protection, causing vaccines to be ineffective even when the protection left from mom isn’t enough to protect the puppy from disease. After a puppy is about 3 months old, maternal antibodies are low enough not to interfere, so the puppy needs at least two vaccines after maternal antibodies have disappeared to be protected.

The other part of prevention is avoidance. Especially when there are outbreaks of a cough in an area, you should avoid bringing your dog to places where dogs congregate. In some circumstances, of course, it is not possible to avoid a kennel, the veterinarian’s office, or even the grooming salon. When this is the case, limit the length of a stay and find a kennel with good ventilation and outdoor access. For animals who are prone to more serious illness from CIRD, finding a pet sitter or at-home groomer is the best situation. 

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Additional information on canine distemper

The canine distemper virus is one of the possible viral causes of CIRD. There are some very important differences, however, between distemper and the other respiratory pathogens.

Clinical signs of distemper (e.g., a dry, hacking cough) can be identical to those of other causes of CIRD. In about 10% of cases, though, neurological signs (seizures, tremors) can occur. In some cases when neurological signs are present, the dog will recover completely; in other cases, the neurological signs remain for life. In rare cases, a dog will appear to recover from respiratory disease and then will develop neurological signs weeks later.

Distemper more frequently causes pneumonia than the other causes of CIRD. In addition, distemper infects more than just the respiratory system, so a variety of other signs can occur (neurological but also urinary symptoms and gastrointestinal signs like vomiting and diarrhea). In young puppies, distemper is frequently associated with a high fatality rate. Most adult dogs, particularly those with partial immunity from a recent vaccination, will survive.

Unlike most CIRD pathogens, distemper has a longer incubation period — the period between when a dog is exposed to a disease and when the dog starts to show symptoms. The typical incubation for distemper is 10 to 14 days, though it can be as long as a month.

Distemper can also be shed for long periods of time, which means a dog who is no longer showing any symptoms can still be contagious to other unprotected dogs. Shedding typically lasts for about a month, but it can last for several months in some cases. Contagiousness can be monitored by repeating respiratory PCR testing; consecutive negative tests can confirm that a dog is no longer contagious.

Treatment for distemper is symptomatic, as it is a virus. Antibiotics are often administered to protect against or to treat pneumonia. Anti-convulsants and muscle relaxants can control some of the neurological signs. If gastrointestinal signs are present, medications to help with nausea and diarrhea can be administered. And fluids are often given to the dog to maintain hydration during periods of decreased appetite and vomiting or diarrhea.

While distemper is a more serious cause of CIRD, even dogs with distemper can survive, depending on the dog’s previous vaccinations, age, and concurrent illnesses. Distemper is more widespread than many people realize (it’s common in many regions of the southern U.S.), but it is important to keep in mind that it’s not the death sentence we once thought. Though distemper can be very serious or fatal in some cases, many dogs do well and go on to live completely normal, happy lives.