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What is cat flu

Cat flu (also known as feline upper respiratory tract disease) is a general term used to describe a common set of symptoms of the upper respiratory tract in cats. The disease may be mild, restricted to an outbreak of sneezing which improves without treatment, or more severe, leaving kittens with chronic disease, and can even be fatal in kittens, old cats and immunosuppressed cats. In all cases, it is highly infectious, spreading rapidly in a group of cats.

See our full guide to cat vaccination

Written by Dr. Mariella Roberts, Veterinary Surgeon, Animal Trust Vets CIC | Published January 2025 | This advice is for UK pets only

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Symptoms of cat flu

The incubation period following infection is usually just a few days (2-10 days). After this, typical clinical signs develop which include sneezing; snotty nose; weepy eyes; lethargy; not eating; fever; cough, and sore throat; and mouth ulcers. The severity of these signs varies considerably – in some cats the signs are very mild and transient, in others they may be very marked and severe.

When to contact your vet

When flu symptoms are noticed, especially in kittens they can worsen quickly.

Diagnosis of cat flu

Diagnosis by the vet is usually based on the typical signs, associated with the cat flu virus, and the exclusion of other causes. It is possible to confirm a diagnosis and to investigate which virus(es) are involved, but this is often not necessary. 

Treatment of cat flu

Treatment of cat flu is largely symptomatic and supportive. Your vet may want to do some additional tests if they are concerned about the extent of the disease (e.g. the possibility of a chest infection) or if they are worried about complications (such as infection with FIV or FeLV). Treatments include Treatments include | Anti-inflammatories: to reduce high temperature and inflammation around the throat. | Mucolytics: to break down the mucus in your cat’s nose and help breathing. Affected cats often do not want to eat so the use of soft, aromatic foods gently warmed will help to tempt the cat to eat. | Eye drops: lubricating eye drops such as artificial tear drops can help to soothe eyes, and antibiotics eye drops will be given if your cat's eyes have a bacterial infection. It is important to finish the whole course of treatment even if the eyes look better. | Antibiotics: will not kill viruses and will only be given if there are secondary bacterial infections; again, it is important to finish the course of antibiotics prescribed even if the cat looks better. | Topical antiviral ointments: can help to manage cat flu-associated eye disease, discharges from the eyes and nose should be gently wiped away using damp cotton wool; the cat should be kept warm and comfortable.

Prevention of cat flu

Vaccination is the best way to prevent this disease and reduce the risk of it. These vaccines are important for all cats, irrespective of how they are kept (even if kept indoors), as the disease is everywhere. | Hospitalization if the cat is still not eating with the use of a feeding tube and fluids into the bloodstream may also needed to avoid dehydration. | Barrier nursing and disinfection: if there is more than one cat in a household, it is important to try to minimise the risk of infection being spread to the other cats. This is not always possible, but in addition to ensuring that all cats are vaccinated, where possible a cat showing clinical signs should be isolated, and separate food bowls and litter trays should be used and disinfected. These viruses are susceptible to most disinfectants, such as household bleach, ask your vet for more advice.

Outlook

Most cats that recover from the cat flu virus will become carriers. Carrier cats usually show no sign of illness but may shed the virus in saliva, tears, and nose secretions, and can be a source of infection to other cats.

Although almost all cats infected with cat flu virus will remain long-term carriers, many of these will never shed significant amounts of virus. Others may shed the virus intermittently, especially during times of stress. Some cats may show mild signs again when they shed the virus, but most do not. Carrier cats in a breeding colony are a source of risk to their kittens, as the stress of kittening may induce shedding of cat flu virus.

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