Cat flu, like its human counterpart, occurs in epidemic form from time to time. Over the past few weeks veterinarians have been treating quite large numbers of cases.
Cat flu or feline viral rhinotracheitis is a viral disease. Two groups of viruses are responsible and within these two groups there seems to be a number of strains. The disease is highly contagious — infection usually being by droplets sneezed or coughed into the air by an infected cat.
Cats confined inside with an infected animal of course are more liable to become infected but those living outside can catch the disease from the cat next door or the itinerant stray that comes to steal its food.
A less important means of spread is from infected saliva or nasal discharge left near feeding or water bowls or transmitted from cat to cat by humans. The virus does not live a very long time in the open air.
The infected cats usually take from 4 to 7 days to show symptoms and the first sign of the disease varies greatly from case to case. Usually, the cat starts to sniffle and give an occasional sneeze which gradually becomes more frequent and more violent.
The eyes start to run and the lids can become very swollen forcing the cat to keep its eyes almost completely closed. At first, the cat does not appear very sick but as the disease causes its nose to become more congested its sense of smell is affected and it goes off its food.
The virus frequently attacks the tissues inside the mouth producing ulcers on the tongue and palate and causing the cat to dribble.
In the present outbreak of the disease some cats develop a very sore throat — lose their voice, refuse food, and have a very high temperature. Whether this is a variation of the more typical disease or if a different virus is present, is not clear.
As with any virus disease, secondary bacterial infection can occur and the disease can travel further down the respiratory tract and cause pneumonia. Very young animals become more seriously ill than healthy adults in good condition. Usually more exotic breeds such as Siamese and Burmese take longer to throw off the effects of the virus than pets of more mixed backgrounds.
Treatment of any virus disease is not specific. Antibiotics are frequently administered to control secondary infection. Lately a drug has become available which helps to free the nasal passages when blocked with thick mucous secretions and this seems to make the cat much more comfortable. If the cat is not eating, fluids are administered by injection to stop the cat from becoming dehydrated and to supply some nutrients.
A combined vaccine against the two major virus groups causing cat flu has been available for some time. As with human influenza vaccines the results have been somewhat variable and at times disappointing.
The initial vaccination is given in two doses, 3 to 4 weeks apart. Some cats, after the first injection, have developed symptoms of the disease but these have usually been mild and of short duration.
A single vaccination is then given annually. Care must be taken not to give the vaccine to cats incubating the disease or that have been in contact with the disease a short time before.
Some Siamese and Burmese cats have caught the diseases even after being vaccinated. Despite this, most veterinarians still feel that the vaccination is worthwhile in cats that are likely to become exposed to large populations of cats such as in catteries or breeding establishments.
One of the problems of control of the disease is the carrier animal. Some cats after infection and apparent recovery, carry the virus lodged in the mucous membranes of the nasal passages.
Shedding of the virus from these reservoirs of infection can occur when the cat is under some extra stress such as at the mating time, after having kittens, being boarded, or shown.
It is from these sources that subsequent litters of kittens or in-contact animals are infected and a new epidemic has begun. Immunity from the natural disease is probably only about 6 weeks so a cat can become infected many times in its lifetime.