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What Exactly is Cat Flu?

Informative image: cat flu

What is it?

Cat flu looks very similar to the cold and flu viruses that we humans are prone to catching. However, it is in fact not one single disease, but a combination of viruses and bacteria with similar symptoms.

What causes it?

Because there are several types of offending germ (although 90% of cases are caused by one of the two viruses), it is a tricky ailment to conquer:

●     Feline Calicivirus – generally causes milder symptoms, but it can bring out ulcers in the mouth and sometimes painful, swollen joints.

●     Feline Herpes Virus – this is typically more aggressive, causing severe runny noses and sore eyes. Once infected, it stays in the cat’s system for many years, meaning it may recur whenever they are stressed or ill.

●     Bordetella bronchiseptica– this is the bacterium also known as ‘kennel cough’ in dogs, whereas in cats it causes ‘flu symptoms.

●     Chlamydophila felis - a form of chlamydia bacteria, mainly causing runny eyes.

Informative image: cat flu eye discharge

How is it spread?

Like the human disease, cat flu can be spread by close contact with other infected animals, in the secretions from the eyes and noses of infected animals.

Calicivirus and Bordetella can survive outside the body for about two weeks, which makes them extremely difficult to eradicate. These organisms are spread either by direct cat-to-cat exchanges or from surfaces and objects that have come into contact with a virus particle.

Herpesvirus and Chlamydophila are much more fragile, and only last a day or so in the environment, so direct cat-to-cat spread is most important.

Although as a general rule cat flu isn’t a serious risk to health in most cases, it is a nuisance and very unpleasant for your cat to contract.

What does it do?

There are some pretty obvious symptoms that can be spotted easily such as a running nose, sore or ulcerated eyes (look for tear stains – the fluid that seeps out is stickier than normal tears so remains on the fur around the eyes) and dribbling which is often a symptom of mouth ulcers. Sneezing is common, and sometimes cats will cough as well.

Additional effects of cat flu can include lethargy, aching muscles and joints, a high temperature, most of which are difficult to spot but combined with the above signs you will definitely notice your pet is feeling under the weather!

In the majority of cases, the effects are not long term but some cats do end up retaining a snotty nose for an extended period after they have recovered. Most unvaccinated cats will remain carriers of the herpes virus for a long time (possibly for life) after their symptoms have disappeared; and occasionally cats become very sick and require hospitalisation.


Prevention is far better than cure! Routine annual vaccinations are the key to keeping cat flu at bay as they will protect against infection. Even if a vaccinated cat is unlucky enough to become infected, the symptoms will be milder and they will transmit the organisms less efficiently to their friends and relations. The normal annual jabs will protect against herpes and calicivirus; there is no vaccine for cats against Bordetella, but there is against Chlamydia - talk to one of our vets if you’re concerned.

*** Cat Vaccination Amnesty until the end of May 2016 learn more here and save on costs!***


Whatever the organism, good nursing care is the mainstay of treatment. It is crucial to keep them warm and cosy, and to make water available. You should encourage them to drink where possible to avoid dehydration; water will also keep the mouth moist and make any ulcers less painful.

Your cat may have a reduced sense in smell and be reluctant to eat (a true sign of an ill pet!) so it is often necessary to tempt them with soft and strong smelling foods, like cooked fish, to give them the energy to fight the infection. The mushy texture will also be easier to swallow if their mouths are sore.

Sometimes our vets will prescribe human medicines to alleviate the eye problems in cats with herpes virus. In addition, the amino acid lysine can be effective at reducing the symptoms, and is available as a paste for food. Often, antibiotics will be prescribed to prevent secondary bacterial infections, such as pneumonia; and to combat Bordetella and Chlamydophila.

Cat flu isn’t a fun experience for either pet or owner - it’s never easy to see our animals in a state of discomfort - but with some good old fashioned TLC and some advice from one of our vets, there is every chance your companion will rapidly return to normal.

If you think your cat has cat flu, call us for advice as to whether or not you should bring them in for any treatment.