From time to time an infectious respiratory disease makes its appearance in dogs. It is not fatal and can be quite transient, but often it causes severe discomfort and requires veterinary attention.
The disease is called Laryngotracheitis, which is merely a description of the tissues affected by the inflammation. Its common name is kennel cough, which is misleading, as dogs that have never been kenneled can contract it.
The disease is highly infectious and can spread rapidly whenever large numbers of dogs meet. A single coughing dog can spread the disease far and wide if taken to a dog show, obedience classes, boarding kennels or even when socializing at the neighborhood shops.
The cause of kennel cough can be one of a number of viruses. As with any initial viral infection, secondary bacterial infection occurs and the severity of the disease probably depends on the type of secondary infection occurring after the initial infection. The dog’s general health and conditions under which it is kept also play a part in determining the severity of the infection.
The organism thought to be responsible for most outbreaks of kennel cough is a virus called canine adenovirus type 2. This virus is very similar to that which causes, infectious hepatitis in dogs. Unlike the canine hepatitis virus, or canine adenovirus type 1, it does not invade tissues other than that of the respiratory tract.
After exposure to an infected dog, it usually takes 5 to 7 days for kennel cough symptoms to occur.
- At first, the dog may give only an occasional cough after excitement or exercise or after a bout of barking.
- In some dogs, the disease goes no further but in others, the cough gradually becomes more frequent and bouts of coughing more severe until any exertion induces a loud rasping cough followed by a retching as if to dislodge something from the throat.
- The dog does not appear sick otherwise and continues to eat. If the disease process is prolonged and secondary bacterial infection occurs, the throat tissues can become sore and the dog is then disinclined to eat.
- The dog’s temperature may be elevated at this point and the infection may extend further down the respiratory tract, with more serious consequences.
Treatment is advisable if the dog’s cough is increasing in frequency after 2 or 3 days. Antibiotics are given to treat secondary infection and these are often given in conjunction with a tablet to break down any thick mucous secretions in the respiratory tract.
Anti-inflammatory agents are often used to reduce the inflammation in the throat and larynx. If coughing is very pronounced, cough mixtures are also prescribed. The dog should be confined as much as possible as any excitement or overexertion induces further paroxysms of coughing.
Contact with other dogs should be avoided to limit the spread of the disease. Sleeping quarters should be sheltered and dry, but keeping the dog in artificially heated areas should be avoided as the drying effect of the inspired air further irritates the already inflamed tissues.
Dogs that have recovered from kennel cough do not seem to have a very long-lived immunity to the disease. Some vaccine manufacturers have incorporated an attenuated form of the adenovirus type 2 in their distemper/hepatitis vaccines.
How effective this is in protecting dogs from kennel cough is not known. Its main advantage, however, will be that it avoids one of the complications in the use of the conventional attenuated canine hepatitis virus, or adenovirus type 1.
A very small percentage of dogs develop a corneal opacity approximately 10 days after vaccination. This is reversible but can be quite alarming to the owner.
With the use of DA2PP, the adenovirus type 2 vaccine combined with distemper, this reaction is eliminated. If it gives protection against kennel cough, it is an added justification for its general use.