Cat flu is a common and highly contagious disease in unvaccinated cats of all ages. It tends to be particularly severe in kittens.
The two viruses associated with cat flu are Feline Viral Rhinotracheitis (FVR) and Feline Calicivirus (FCV). Unlike most bacterial infections, viruses are very difficult to treat and specific anti-viral treatments are generally not available. These viruses are more likely to remain within the system for long periods of time, although symptoms of the infection may not always be apparent. It is therefore unfortunate that a ‘flu' infected cat is likely to retain the virus in its system for life.
Signs of cat flu are similar to those for colds and flu in people. It can cause inflamed and runny eyes, discharge from the nose, sneezing, coughing, loss of appetite and sometimes mouth ulcers. The discharge from the nose and eyes generally begins as a clear colour. If the cat develops a secondary bacterial infection, the discharge will change to a yellow/green colour.
Symptoms can be minor or severe, depending on the cat's age, breed, vaccination status, and whether or not he or she has previously been infected.
Inhaling aerosol droplets sneezed or coughed out by other, infected cats is the most common cause of infection.
Clinically ill cats or those suspected of being carriers should be isolated or handled last when in multi-cat households or boarding facilities.
In a home environment, food bowls and litter trays of flu cats should be washed separately.
Most cats that have been infected with cat flu enter what is called a ‘carrier state', where the virus remains in the system, but symptoms are not always apparent.
FVR carriers are only infectious when they are shedding the virus. Viral shedding can be continual or intermittent. Carriers most commonly start shedding the virus during periods of stress e.g. re-homing, boarding, new family member.
FCV carriers continue to excrete the virus after they are initially unwell. FCV carriers excrete continuously so are always potentially infectious to other cats, particularly unvaccinated ones.
If vaccinated as a young kitten it is unlikely your cat will contract flu, as he or she will already have developed antibodies against the disease. However, if your vaccinated cat does contract flu' the severity of the virus is drastically reduced.
If your cat is a carrier, vaccination is still recommended for two reasons:
1. Any symptoms that develop will be less severe.
2. It is extremely unlikely that your cat would be a carrier of both FVR and FCV, therefore vaccination will prevent your cat catching the other strain of flu.
Vaccinations should continue to be given by your vet once every year.
Cat flu carriers can go through life with minimal problems, living a happy life like most other cats. The only time your cat will ever feel unwell is when they are showing clinical signs. As mentioned earlier, it is unlikely that clinical signs will appear unless your cat is exposed to a stressful situation or change. So if you can provide a happy stable life for your cat flu carrier, it is unlikely it will ever be a problem.
Talk to your vet about treating symptoms when they appear, if they are minor it is unlikely treatment will be needed. However if a secondary bacterial infection develops, antibiotics may be required. We need to be mindful that weeping eyes can quickly become more severe and may cause corneal ulcers to develop on the eye. Prompt veterinary attention is necessary in this case.
For all of the reasons listed above it is a great idea to let your cattery know. Your flu carrying cat can be isolated so s/he can receive special attention in the cattery and other visiting friends can avoid catching this debilitating virus.