This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Note for Pet Owners:
If you have a cat with cat flu there are some important guidelines that you should follow :

Always give the medications that your veterinarian has prescribed at the correct dose and at the correct times

Keep your cat's airways clear by wiping away dried discharges and other debris from around the nose

Don't keep your cat in a hot, stuffy room. Provide plenty of fresh air and ventilation.

Keep your cat away from other cats - especially kittens, to prevent transmission of the infection.

If you have a cat without cat flu :

Consider having your cat vaccinated - speak to your veterinarian

Always have your cat vaccinated BEFORE it goes into situations where it may be exposed to infection e.g. cat shows, catteries.

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Cat flu is a general term used to describe a group of infectious diseases which affects the upper respiratory tract - including the eyes, nose, pharynx, mouth, larynx, and windpipe (trachea). Occasionally they involve the lower respiratory tract - the bronchi and lungs. 

This group of infectious diseases includes viruses, feline rhinotracheitis virus (herpes), feline calicivirus, feline reovirus, and non-viruses such as Chlamydofila felis Bacterial infections (e.g. bordatella bronchiseptica, staphylococcus epidermidis and streptococci) and mycoplasma are included in the group, but they are usually secondary invaders.

Breed Occurrence
All cats are susceptible to cat flu.

The presenting signs do overlap between infections with the different organisms, but sneezing, a high body temperature and general dullness are common to all of them. Some signs are more typical of specific infectious organisms than others. Recurrent and persistent conjunctivitis - with inflammation of the eye and a purulent bilateral discharge is typical of Chlamydia infection, whereas calicivirus frequently causes sever ulceration in the mouth. Rhinotracheitis virus causes corneal ulcers and is most likely to affect the lower respiratory tract, which can lead to secondary pneumonia, as well as systemic effects such as abortion in infected queens.

Some cats can become chronic carriers of infection, and immune-compromised cats may never fully recover developing chronic rhinitis.

If untreated mild cases of cat flu can progress to pneumonia due to secondary infections. 


The infectious agents that cause cat flu can be identified from a variety of tests including isolation from swabs, and from blood tests (measuring antibodies) in some cases. Unfortunately interpretation of the results can be misleading. For example, some of the viruses that can cause the signs of cat flu may be found in samples taken from healthy, unaffected animals. This means that a cat's immune system probably has to be compromised for it to develop the disease.

In prolonged cases or cases unresponsive to conventional treatment it is wise to screen for the presence of feline leukaemia virus (FeLV) or feline immunodeficiency virus (FIV) as these may compromise immune response making recovery difficult.


There is no specific treatment for the viruses that cause cat flu but symptomatic treatment and care is needed. The exception to this rule is for corneal ulcers caused by feline rhinotracheitis virus, as these can be treated with the antiviral agent trifluoridine - which is applied 8-10 daily to the eye. Providing an infected cat is able to mount a normal immune response to the infection, viral cat flu is a self-limiting disease and most cats recover in 2-3 weeks. A small number of cats become chronic carriers of the infection- particularly if they have concurrent feline leukaemia virus (FeLV) or feline immunodeficiency virus (FIV) infection.

Bacterial infections are treated with antibiotics - usually ampicillin, amoxycillin, tetracyclines or potentiated sulphonamides.

Chlamydia infection is treated with tetracyclines - usually given by injection for a week, as local administration into the eye is less effective.

In all cases the opening to the nose should be kept clean by wiping away collected debris and discharges. Sometimes the use of a nebuliser or decongestants (e.g. pseudoephidrine) is recommended in severe cases.

The prognosis is good for most individuals, but cats with FeLV, FIV or other forms of immune-suppression may not do well.

Long term problems
Chronic carrier states are a problem as these cats may act as a reservoir for infection of other cats.


Updated January 2016