Cat flu is a common upper respiratory tract infection in cats, and some of the symptoms are similar to a human cold or flu. It usually affects the nose, throat, eyes and airways, but it is not the same as human flu.

Many adult cats make a full recovery with veterinary guidance and supportive care, but it can be more dangerous for:

• Kittens
• Elderly cats
• Unvaccinated cats
• Cats with weakened immune systems
• Cats with existing health conditions

If you notice your cat sneezing, seeming unusually tired and lethargic, presenting with runny eyes or a runny nose, or refusing to eat, contact your vet. Vaccination can reduce the severity of the disease, but it may not prevent infection.

What Is Cat Flu?

Cat flu is a general term we use to describe infectious respiratory disease in cats. Its symptoms usually affect the eyes, nose, mouth and throat, and they may affect the lungs and airways in more serious cases.

The term "flu" is slightly misleading in this case. The condition is not usually caused by the same type of influenza viruses that affect humans — it is almost always linked to feline-specific viruses. Vets are more likely to refer to it as:

• Feline upper respiratory infection
• Feline upper respiratory tract disease
• Cat respiratory infection

An owner whose cat has the virus is likely to notice sneezing, watery or sticky eye discharge, nasal discharge, tiredness and a reduced appetite. There may also be mouth ulcers or drooling. Mild cases can improve, but it is important to get the right care to avoid it becoming serious.

What Causes Cat Flu?

There are two main viral causes of cat flu. One is feline herpesvirus, often shortened to FHV or FHV-1. The other is feline calicivirus, often shortened to FCV. These may present in different ways:

• FHV: This tends to cause sneezing, eye problems and nasal discharge.
• FCV: Symptoms tend to include mouth ulcers and sometimes lameness in more severe cases.

Around 80% of cat flu cases are caused by feline herpesvirus, feline calicivirus, or both.

Secondary bacterial infections can sometimes make symptoms worse. Potential bacterial contributors include bordetella, chlamydophila felis and species of mycoplasma. Knowing the exact cause isn't always necessary for mild cases, but vets may recommend tests in severe or recurring cases.

What Are the Symptoms of Cat Flu?

Symptoms of cat flu are quite diverse, though they often resemble symptoms of a human cold or flu. They can vary from mild to severe, and some cats can become very unwell. Look out for any of the following symptoms:

• Sneezing
• Runny nose
• Watery, sticky or sore eyes
• Nasal congestion
• Fever
• Loss of appetite
• Tiredness or sleeping more than usual
• Drooling
• Mouth ulcers
• Sore throat
• Coughing
• Hoarse or lost voice
• Difficulty eating
• Dehydration
• Breathing problems or pneumonia (in severe cases)

Some cats may stop eating because they can't smell their food properly, their throat or mouth hurts, or they generally feel unwell. When a cat stops eating and/or drinking, it should be seen by a vet immediately.

Symptoms may start to appear around 2–10 days after exposure to the virus, though it can take up to 2 weeks.

Is Cat Flu Serious?

Cases of cat flu can be mild in some healthy adult cats, but it should never be ignored. The practical warning signs that your cat is in danger include not eating or drinking, struggling to breathe, severe eye pain, a thick yellow or green discharge and extreme lethargy.

Cat flu can be more dangerous for:

• Kittens
• Senior cats
• Pregnant cats
• Unvaccinated cats
• Cats with weakened immune systems
• Cats in rescue centres, catteries or shelters

Possible complications that can make a cat seriously ill include dehydration, eye ulcers, pneumonia, severe mouth pain and long-term nasal inflammation. Recurring flare-ups of symptoms can also take a toll on a cat's body.

We recommend that you always contact a vet if cat flu is suspected, especially in vulnerable cats. Litter Sense cat litter can help, as it changes colour when a cat's urine is abnormal, giving you an early warning sign that something is not right in your cat's body.

How Does Cat Flu Spread?

Cat flu is extremely contagious between cats. It spreads through exposure to an infected cat's bodily fluids. Cat flu viruses can survive outside the body for anything from 7 days to a month, so it is quite easy for a cat to be exposed.

Common sources of the virus spreading include:

• Saliva
• Nasal discharge
• Eye discharge

These bodily fluids can spread the virus through a sneeze, direct contact between cats, shared food/water bowls, bedding, toys, grooming equipment and more. This is one reason why hygiene is important in a multi-cat home.

If you have an infected cat, it is best to keep it separate from other cats while it is unwell. Always follow your vet's advice throughout this process.

How Is Cat Flu Diagnosed?

Vets often diagnose cat flu based on the symptoms that are present. This may include a physical examination of the cat in the clinic. They will also often ask about vaccination history and contact with other cats.

Tests may be needed in some cases. These could include:

• Eye, nose or throat swabs
• PCR testing
• Bacterial culture in complicated cases

Testing is more likely if symptoms are severe, or if they keep coming back. Cats in multi-cat households are also more likely to undergo testing, or further investigation may be needed if treatment is not working as expected.

How Is Cat Flu Treated?

There is no single or instant cure for most cases of cat flu. Generally speaking, a treatment plan is made to attempt to reduce symptoms, prevent complications and support recovery. There are various approaches a vet might take, including:

• Anti-inflammatory medicine
• Eye drops
• Medication to loosen mucus
• Pain relief
• Antibiotics (if a secondary bacterial infection is suspected)
• Antivirals in selected cases
• Fluids if dehydrated
• Hospitalisation if the cat is very unwell

Remember that antibiotics do not treat viruses — they are only relevant if there are secondary bacterial infections. Antivirals can take several weeks to work and there is no guarantee they will be effective.

Never give human cold, flu or pain medication to a cat unless you are specifically instructed to do so by a vet.

How Can You Care for a Cat With Cat Flu at Home?

When it comes to cat flu, home care should support a vet's advice, not replace it. Your vet will give you guidance on what to do, and your at-home care should aim to complement the treatment the vet has provided.

Here is a practical care checklist for you to follow:

• Keep your cat warm, quiet and comfortable
• Reduce stress
• Gently wipe discharge from the eyes using cotton wool dampened with warm water
• Use a separate piece of cotton wool for each eye
• Encourage drinking
• Offer wet food
• Warm food slightly so it smells stronger
• Try strong-smelling foods like tuna, sardines or pilchards
• Keep bedding clean
• Clean food and water bowls daily
• Clean the litter tray regularly with pet-safe disinfectant

In some cases, steam from a warm bathroom can help loosen mucus. But a cat should never be forced, overheated or left unattended. If you notice that your cat stops eating, contact your vet right away.

Can Cats Recover From Cat Flu?

Many cats recover from the initial illness with appropriate care. For most cats, symptoms should improve within one to two weeks with treatment. However, some cats may become long-term carriers of the virus.

If a cat becomes a carrier, they will still usually return to health through recovery. However, they will still carry the virus, so symptoms might flare up again during times of stress or illness and will need care again.

Feline herpesvirus can remain latent in the body for the cat's lifetime. This is why prevention and vaccination are important, and stress reduction and good hygiene are essential after recovery.

Frequently Asked Questions About What Is Cat Flu

Is cat flu the same as human flu?

No, cat flu is a feline respiratory illness. It is usually caused by feline herpesvirus, feline calicivirus, or related infections. But it can resemble a human cold or flu with sneezing and nasal discharge.

Can indoor cats get cat flu?

Yes, but their risk may be lower than for outdoor cats. Indoor cats may be exposed through new cats, boarding, vet visits or contaminated hands. This is why it's still important to get your indoor cats vaccinated.