Kennel Cough is usually caused by several infectious agents working together to damage and irritate the lining of the dog's trachea and upper bronchii. The damage to the tracheal lining is usually superficial, but exposes nerve endings that become irritated due too the passage of air over the damaged tracheal lining. Once the organisms are eliminated the tracheal lining will rapidly heal. The most common organisms associated with Kennel cough are the bacteria called Bordetella bronchiseptica (Although it rarely occurs, Bordetella bronchiseptica infection can be transmitted from animals to humans and so it is a Zoonosis) and two viruses called Parainfluenza virus and Adenovirus and even an organism called Mycoplasma
The 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 vapour or dust particles. The airborne organisms, if inhaled by a susceptible dog, can attach 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.
Even in the most hygienic, well ventilated, spacious kennels the possibility of a dog acquiring Kennel Cough exists. Kennel Cough can be acquired from your neighbour's dog, grooming salon , from a Champion show dog at a dog show, from the Veterinary clinic , where your dog just came in for treatment of a cut pad. Try not to blame the kennel owners if your dog develops Kennel Cough shortly after a stay at the kennel. There may well have been an infected dog, unknown to anyone, that acted as a source for the other dogs in the kennel. Many dogs will have some protective levels of immunity to Kennel Cough after minor exposures to the infective organisms and simply will not acquire the disease even if exposed. Other dogs may never have had immunizing subtle exposures and they may well be susceptible to the Bordetella bacteria and associated viruses and go on to develop the signs of coughing and hacking.
The reason this disease appears common is that wherever there are a number 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(hence Kennel Cough). The same can be said about the colds spread from human to human. They are more likely to occur in a populated, enclosed environment such as an airplane, lift 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
Many dogs that contract Kennel Cough will display only minor signs of coughing that may last seven to ten days and will not require any medication at all. The majority of dogs with the disease continue to eat, sleep, play and act normally, except for that irritating, dry, non-productive cough that appears so persistent. It is always a good idea to have any dog examined if coughing is noticed because some very serious coughs can have other causes. For example, Heart disease might present with a similar sounding cough. Your vet, after a thorough physical examination and questioning regarding the dog's recent environment, will be able to establish if the dog's respiratory signs are from kennel Cough or some other respiratory problem.
A lot of dogs exposed to all sorts and numbers of other dogs, will never experience the effects of Kennel Cough. Some dog owners, though, 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 otherwise expose their dog to populations of other canines. Since the chances of exposure and subsequent infection rise as the dog comes in close proximity with 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 does 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 for will vary greatly. How often to vaccinate seems to have a subjective and elusive answer.
If you vaccinate with just the commercial Kennel Cough vaccine alone (contains only the Bordetella agent), it 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 dogs. The intra-nasal Bordetella vaccine may produce immunity slightly faster than the injectible vaccine as it is absorbed through the mucus membrane
NOTE: Any vaccine takes days to weeks to stimulate the dog's protective immunity to the disease. Vaccinating a dog the day it is exposed to disease may not be protective. If you plan to board your dog, or protect it from exposure, remember to vaccinate a few weeks prior to potential exposure to allow full protective immunity to build up
What is zoonosis?
Zoonosis (pronounced zoo-on-no-sis) is any infectious disease that may be transmitted from animals, wild or domestic, to humans. The simplest definition of zoonosis is a disease that can be transmitted from animals to humans. A slightly more technical definition is a disease that normally exists in animals, but can infect humans. On other occasions it may be used to mean a disease that can complete its life cycle without a human host. None of these are wrong, although the first is too simplistic.