Unlike their owners, animals do not tend to get more illnesses in winter time.
In fact veterinarians often have a quiet time during the very cold months as most pets are safely locked up inside and have to be obviously very sick to persuade their owners to venture into the cold to take them to the surgery. There is also a marked decrease in road accidents as most dogs do not get taken for a walk after dark.
One disease in cats often shows up during the winter months, feline influenza. The disease is important, as the incidents rises with the increasing population of cats and can be the curse of breeders that necessarily have to maintain large numbers of cats in confined spaces.
Feline influenza is a virus disease, caused by two different viruses. One virus is relatively large and belongs to the same family as the herpes virus that infects man. The other is small and has at least 14 different strains.
Both viruses occur world wide and each produce symptoms in the infected animal that are indistinguishable clinically, so that for the purposes of this article we will refer to the disease they both produce as feline influenza.
Infection is caused by contact with virus particles shed from an infected cat. This can occur when two cats sniff each other or use the same feeding bowl or sleeping accommodation. Airborne infection is another important source of infection.
The virus can be transported in droplets sneezed into the air in the vicinity of a cat when outside, or more readily, when in a confined space with an infected cat.
The incubation period is two to seven days, and the early clinical signs can be very variable. Often a strong healthy cat may show nothing except a watery discharge from one or both eyes. This gradually becomes worse and the lids begin to swell.
Soon the cat may begin to sniffle and sneeze and go off its food. The disease may develop no further and the animal is completely recovered in a week.
More typically the disease process is more acute, causing severe conjunctivitis, frequent sneezing and dribbling of saliva from the mouth. If the mouth is opened large ulcerated areas on the tongue and pharynx are quite obvious.
Sneezing may become so vigorous and frequent that small blood vessels in the nasal passages are ruptured and the cat may sneeze out pure blood.
At this stage the animal usually refuses all food and drink and will breath with its mouth open because of the congestion of its nasal passages. Secondary bacterial infection can occur, which complicates the picture, and the organisms can invade the lower respiratory tract, causing pneumonia.
A characteristic of the disease is that recovered animals can remain carriers of the virus and be apparently healthy unless their resistance is lowered by some further stress. Females can suddenly develop the disease after the third week of pregnancy.
Animals placed in boarding kennels caged during a cat show or travelling may start to sneeze or have watery eyes. Some animals show none of these signs but nevertheless shed the virus, which can infect other animals.
Newly born kittens may become infected from an apparently healthy mother. The first signs of the disease in very small kittens are inflamed and swollen eyes. The kitten keeps the eyes closed in strong light. The disease can be very severe in young kittens, causing pneumonia and rapid death.
Treatment of any virus disease is not specific, as viruses are not susceptible to antibiotics. One of the problems with the disease is that infected animals lose their sense of smell and therefore go off their food, which decreases their resistance even further. Antibiotics are administered by the veterinarians to control secondary bacterial invaders.
Drugs are used to reduce the inflammation in the respiratory tract and to clear the nasal passages of accumulated mucus. Vitamins are administered to try to increase the animal’s natural resistance, and with cats that have not eaten for some time nutrient fluids are administered intravenously.