Kennel cough most commonly affects dogs, but is occasionally reported in cats. The disease is caused by infection with one or more infectious agents, which can be viral (parainfluenza, adenovirus), bacterial (bordatella bronchiseptica), or a combination. In most cases the infection remains in the upper respiratory tract, causing a distinct ronchus, sometimes gagging cough. Often the patient exhibits clear to yellow or green nasal discharge, and the lymph nodes of the neck are enlarged. Most dogs presenting with kennel cough have a history of being in situations that predispose them to infection with the disease (see below).
The causative organisms can be present in the expired air of an infected dog, much the same way that human “colds” are transmitted. The airborne organisms will be carried in the air in microscopically tiny water vapor or dust particles. The airborne organisms, if inhaled by a susceptible dog, can attatch to the lining of the trachea and upper airway passages, find a warm, moist surface on which to reside and replicate, and eventually damage the cells they infect.
The reason this disease seems so common, and is even named “Kennel” cough, is that wherever there are numbers of dogs confined together in an enclosed environment such as a kennel, animal shelter, or indoor dog show, the disease is much more likely to be spread. The same is true with the “colds” spread from human to human… they are much more likely to occur in a populated, enclosed environment such as an airplane, elevator, or office. All it takes for contagion to occur is a single source (infected dog), an enclosed environment, and susceptible individuals in close proximity to the source of the infection. Infected dogs can spread the organisms for days to weeks even after seeming to have fully recovered!
Kennel cough is treated with a combination of rest and antibiotics. Left untreated, kennel cough may resolve on its own, but also has the potential to result in pneumonia and even death. In cases where there is secondary pneumonia, or if kennel cough infection is causing debilitating fever, hospitalization with IV fluids, nebulization, and fever reducers is necessary.
Many dogs, exposed to all sorts and numbers of other dogs, will never experience the effects of kennel cough, while otheres frequently come down with the disease It is impossible to predict whether or not a dog will become infected, however, kennel cough is known to be highly contagious Therefore, many owners prefer to take advantage of the current vaccines available that are quite effective in preventing the disease. Usually these dog owners will have to board, show, field trial, or other
dogs, the decision to vaccinate or not to vaccinate varies with each individual circumstance. Generally, if your dog is not boarded or going to field trials or dog shows, you may not have a high level of need for vaccinating your dog against Kennel Cough. If your dog happens to acquire Kennel Cough, it will then have some immunity to subsequent exposures. The length of time these natural exposures and the vaccinations will produce protective immunity will vary greatly. How often to vaccinate seems to have a subjective and elusive answer.
Always keep in mind that vaccinating with just the commercial Kennel Cough vaccine alone (contains only the Bordetella agent) may not be fully protective because of the other infectious agents that are involved with producing the disease. Some of the other agents such as Parainfluenza and Adenovirus are part of the routine vaccinations generally given yearly to tri-yearly to dogs. The intra-nasal Bordetella vaccine may produce immunity slightly faster than the injectible vaccine, and remains my vaccine of choice for kennel cough. It also seems to be associated with a lower rate of vaccine reaction, and serial boosters are not necessary to impart a sufficient immune response, whereas, with the injectable bordatella, for puppies and first time adult dogs that have never before been vaccinated, need a second booster vaccine is necessary to provide sufficient protection.
Roger L. Welton, DVM
Founder and Chief Editor, Web-DVM.net
President, Maybeck Animal Hospital
Article updated 5/20/2014