August is National Immunization Awareness Month, and The Meowing Vet is ready to inform pet owners about the importance of vaccination in reducing your dog’s risk of developing a kennel cough infection.
Learn more about canine kennel cough below…
What is Kennel Cough?
Kennel cough, called canine infectious tracheobronchitis or canine infectious respiratory disease (CIRD) in medical terms, is considered to be one of the most widespread infectious diseases of dogs worldwide. This infectious disease primarily affects the trachea and bronchi. [As a reminder, the trachea (or windpipe) bifurcates into 2 mainstem branches called bronchi, which then enter the lungs to supply air.] The pathogens at play in a kennel cough infection paralyze the epithelial cilia of the respiratory tract, which normally functions to sweep away debris and infectious agents. With the protective mechanisms of the respiratory tract thwarted, exposed dogs are at risk of developing infection.
Kennel cough is highly contagious among dogs. It is transmitted either from direct contact with an infected dog or by aerosolized pathogens, spread from sneezing or coughing. However, the kennel cough bacteria cannot live for very long out in the environment without a host. Areas of increased exposure include boarding or kennel facilities, dog shows, dog parks, doggie daycare, and pet shops – really wherever a large number of dogs tend to congregate. Young and unvaccinated adult dogs are especially at risk of infection.
Though some degree of sickness is very common among unvaccinated canines, death is, fortunately, uncommon (meaning that kennel cough carries a high morbidity yet low mortality rate). Most cases of kennel cough tend to result only in a mild infection though some cases can be more severe. The kennel cough bacteria can persist in the respiratory tracts of dogs for up to 3 months following recovery from infection, so all other dogs exposed to that animal should be vaccinated. Furthermore, the causative bacteria may be shed not only by sick animals but also by some healthy animals who act as carriers – shedding the pathogens that reside in their nasopharynx. Thus, vaccinating your pet is important to help prevent infection since one can never be sure if other dogs to which your own pet may be exposed are infectious threats.
What causes Kennel Cough?
Kennel cough is primarily caused by the bacteria Bordetella bronchiseptica. Milder, uncomplicated infections result when Bordetella is the only pathogen at play. However, this bacteria can weaken the defenses of the respiratory tract to allow other agents to colonize the respiratory tree, resulting in more severe infections.
The canine parainfluenza virus is a common co-star, working alongside Bordetella to cause a more severe kennel cough complex. Other viruses can also occasionally be involved, including canine adenovirus-1 and adenovirus-2 as well as canine herpesvirus. Rarely, other bacteria alongside Bordetella may also be culpable, including Mycoplasma, Streptococcus, Pasteurella, E. coli, and Klebsiella. Infections involving multiple pathogenic agents besides Bordetella can lead to complicated cases that are much more severe; such infections are more difficult to treat and can result in bronchopneumonia.
Clinical Signs of Kennel Cough
Kennel cough results in an acute (sudden) onset of the following clinical signs in dogs:
- Coughing: loud, goose honk sound; often productive with a foamy or clear liquid
- Gagging after coughing
- May also experience sneezing
- May develop green (mucopurulent) nasal & ocular discharge
More complicated and severe infections can result in:
- Fever
- Decreased appetite (anorexia)
- Bronchopneumonia: the most common signs that your pet may have pneumonia include wheezing noises, severe coughing, increased effort when breathing, standing with the neck held down and the elbows extended outward (abducted), and difficulty breathing
Diagnosis
When you call your local veterinary office to schedule an appointment for your sick dog, your vet may ask you to wait with your coughing canine in your vehicle rather than in the waiting room to avoid exposing other dogs. At your appointment time, you shall then be directly immediately into an exam room or through a separate entrance into the veterinary hospital.
A diagnosis of an uncomplicated, mild case of canine kennel cough is typically determined solely through your veterinarian’s physical examination of your dog. Your vet will listen to your dog’s chest, paying special attention to bronchial and lung sounds to ensure that the coughing is not stemming from a lung or cardiac issue. With uncomplicated kennel cough cases, the lung sounds are normal. The trachea will also be ausculted (listened to with a stethoscope); your vet will likely hear raspy sounds as air passes through the inflamed trachea, which will also be sensitive to the touch, causing your dog to cough upon palpation of the trachea (gentle manipulation of the windpipe).
Most cases of uncomplicated kennel cough are pretty straight-forward to diagnose and treat. However, complicated cases result in more severe clinical signs and may require more diagnostic tests to truly attribute to kennel cough. The most common test performed is a transtracheal wash in which a small amount of sterile fluid is passed directly into your pet’s trachea and then re-collected. (Your pet is typically under anesthesia when this is performed.) This instilled fluid has washed over the inner aspect of your pet’s trachea and come in contact with potential pathogens. The fluid is then analyzed under a microscope as well as submitted to a specialty laboratory for culture and sensitivity testing. The fluid is plated to see if infectious organisms grow from it and then analyzed to determine to which antimicrobial drugs they are most susceptible.
Treatment
Although kennel cough is highly contagious, it is fortunately easily treatable in most cases. Some cases may be self-limiting, meaning your dog will improve on his or her own within 10-14 days without medical treatment. Most cases, however, require at least supportive care through use of a cough suppressant (antitussive medication, such as butorphanol or hydrocodone). To alleviate tracheal and bronchial inflammation, which can further trigger coughing spells, a short course of anti-inflammatory corticosteroids (such as prednisone) may be prescribed. Other vets may prescribe an oral antibiotic to kill the Bordetella bacteria. One of the following special antibiotics may be considered, as these empirical drug choices are efficacious in the respiratory tract: doxycycline, amoxicillin-clavulanic acid (Clavamox®), trimethoprine-sulfamethoxazole, or enrofloxacin (Batyril®).
For complicated cases which result in pneumonia, the results of the culture and sensitivity testing from the transtracheal wash will dictate which oral antibiotic is most effective against the specific infectious cause. In addition to oral antibiotics, the nebulization of an antibiotic (such as gentamicin) is especially useful. Nebulization is the process of converting a liquid medication into an aerosolized formulation – to be breathed directly into the respiratory system where the infection lies. Moreover, other supportive treatments are initiated for these more severe cases. Such care includes maintaining your dog’s hydration status (via subcutaneous or IV fluid therapy), the use of bronchodilators to open up inflamed bronchi in order to make breathing easier, and coupage. Coupage, or thoracic percussion therapy, is the systematic cupping and patting of your dog’s chest by your veterinary team in order to loosen up debris from the lungs to be more easily coughed up and cleared by the body.
Prevention
Vaccination is vital to help reduce your dog’s risk of developing a kennel cough infection. Additionally, limit your dog’s exposure to dog parks and other canine gathering places, especially until your puppy or adult dog is up-to-date on a full kennel cough vaccine schedule. (These areas should be strictly avoided in unvaccinated puppies.)
Though vaccines are very important to help offset outbreaks and prevent your dog from acquiring kennel cough, no vaccine is 100% effective. Since kennel cough can be caused by a combination of several different pathogens, no single vaccine can protect against all these possible combinations. Furthermore, vaccination may be protective for different periods of time, some for up to 12 months while others may only protect certain individuals for 6 months or less. Therefore, boostering your dog’s vaccine at your veterinarian’s discretion is highly recommended to increase the likelihood of protection. Vaccination also helps reduce the severity of infection should your pet still acquire kennel cough and then lowers the risk of co-infection with additional pathogens.
Kennel cough vaccines are quite safe, resulting in no to minimal side effects (the most common of which is mild sneezing or coughing for a couple of days). Several different vaccine options against kennel cough exist, including various injectable, intranasal, and oral formulations.
Injectable Vaccines
Injectable (or parenteral) vaccines are some of the oldest, more traditional products. Options include vaccines against Bordetella only or a combination vaccine against both Bordetella + canine adenovirus-2 (the latter of which also cross-protects against adenovirus-1). Injectable vaccines must be given as a series to be effective. The first dose is administered in puppies as early as 6-8 weeks of age; the vaccine is then boostered every 3-4 weeks until the puppy is 12-14 weeks old. Further boosters are then administered every 6-12 months throughout the adult dog’s lifetime. Injectable vaccinations achieve protection by inducing systemic antibody production so that if your dog is exposed to the causative pathogens, IgG antibodies in the bloodstream will travel to the respiratory tract to help fight infection. Immunity is achieved within 14 days with injectable kennel cough vaccines.
Your dog’s annual DHPP vaccine also helps protect him or her from the canine parainfluenza virus as well as canine adenovirus-1 and -2.
Intranasal Vaccines
Intranasal vaccines are administered exactly as you’d think: a small volume of liquid is squirted into your dog’s nose where it is inhaled. Intranasal vaccines come in either a Bordetella only formula or Bordetella + canine parainfluenza combo. These vaccines can be given to puppies as well as adult dogs. Depending on the manufacturer, only a single vaccine may initially be required or else a series of 2 vaccines separated by 3-4 weeks. Following this initial inoculation, boosters are then administered every 6-12 months depending on your region.
Intranasal vaccines may be a bit unpleasant for some dogs who dislike the odd tickling sensation of having a liquid vaccine instilled inside their nostrils. Other dogs who fear needles may prefer this method of immunization versus injectable vaccines. Whatever your dog’s preference may be, intranasal vaccines do have a major advantage over injectable options. Because intranasal vaccines are administered directly into your pet’s respiratory tract (where kennel cough infections develop), intranasal products offer better protection in the form of IgA immunity. IgA immunity, also called mucosal immunity, is achieved when the development of special antibodies called IgA are triggered to be on the lookout for respiratory pathogens. IgA antibodies not only help fight an infection once it has developed, but these immunological protection cells actually prevent infection from developing in the first place by keeping Bordetella and parainfluenza from adhering to the lining of the trachea and bronchi to begin with. For this reason, intranasal vaccines are more effective at preventing disease, and immunity is achieved within 5 days with these vaccines (versus 2 weeks with injectable options).
Oral Vaccines
Oral vaccines against kennel cough (currently for Bordetella only ) are newer products in which a small amount of liquid is placed in your dog’s mouth to be swallowed. Oral formulations are great because IgA immunity is also triggered without the need to administer a vaccine up your skittish dog’s nose or through a needle into the skin. As with intranasal options, immunity is also achieved within 5 days following vaccination.
Learn more about other vaccines needed by your puppy and adult dog with The Meowing Vet’s articles on Canine Vaccines & Preventative Medicine.
What about Cats?
Kennel cough, also caused by Bordetella bronchiseptica, can occur in felines, too, resulting in an upper respiratory infection (URI) with inflammation of the larynx and pharynx. Though rare, some cases can progress to bronchopneumonia in cats as can happen in some dogs. Affected kitties may shed the bacteria for up to 19 weeks after recovering from infection.
Fortunately, kennel cough occurs much less commonly in cats than in dogs,. Vaccination against Bordetella is also available for cats though it is not administered as frequently to felines due to a lower risk of disease development in comparison to dogs.
In addition to domestic cats and dogs, Bordetella bronchiseptica can also affect wild canids and felids, rabbits, and pigs, though occurrence is quite uncommon.
Click here to learn about other causes of upper respiratory tract infection (URI) in cats.
– Maranda Elswick, DVM
The Meowing Vet encourages you to check with your veterinarian to ensure that your dog’s kennel cough vaccine is up-to-date, especially before your pup participates in doggie daycare or is boarded while you’re on vacation.
