Cat Flu: Signs, Care at Home and When to Call the Vet

At a glance

What it is	An infection of the nose, throat, eyes and sometimes mouth, mainly caused by viruses, often with bacteria joining in
Who's at risk	Kittens, unvaccinated cats, older cats, cats with weakened immunity and cats in busy shelters or multi-cat homes
Main signs	Sneezing, eye and nose discharge, mouth ulcers, drooling, fever, lethargy, not eating
Contagious?	Yes, between cats. It isn't the same as human flu and isn't caught by people or dogs
Can it be prevented?	Vaccination reduces the risk and severity; good hygiene helps limit spread

What it is

"Cat flu" is the everyday name for an upper respiratory tract infection in cats. It affects the nose, sinuses, throat and eyes, and sometimes the mouth. Despite the name, it isn't related to human flu.

Most cases are caused by one of two common viruses: feline herpesvirus and feline calicivirus. Bacteria can also be involved, either as the main cause or as secondary invaders that take advantage of the irritated lining of the nose and throat. Some cats have more than one infection at once.

Cat flu spreads easily between cats through direct contact, sneezing droplets, and shared items such as food bowls, bedding, litter trays and even people's hands and clothes. That's why it's common wherever many cats live together, such as shelters, catteries and breeding homes.

Carrier cats

Some cats who recover become carriers. Cats who have had herpesvirus usually carry it for life. The virus can lie quiet and then flare up again during times of stress, illness or other changes, sometimes causing a mild return of signs. Some cats who have had calicivirus may shed the virus for a period after recovery. Carrier cats may look perfectly healthy but can still pass the infection to others.

Signs to watch for

Signs can range from mild to severe. Look out for:

• Sneezing, sometimes in fits.
• Runny eyes, which may be watery at first and later thicker, yellow or green. Eyes may look red, swollen or half closed.
• Nasal discharge, from clear to thick and coloured, sometimes with a crusty nose.
• Mouth ulcers, which can cause drooling, pawing at the mouth, bad breath or reluctance to eat.
• Not eating. Cats rely heavily on smell to decide whether to eat. A blocked nose can make food seem unappealing, so many cats with flu stop eating. This is one of the most important signs to act on.
• Fever, lethargy and hiding.
• A hoarse voice or coughing, in some cats.
• Lameness, occasionally, with some strains of calicivirus.

Sneezing and runny eyes have other possible causes too, such as allergies, dental disease or something stuck in the nose. Our article on why your cat might be sneezing explains more, and the symptom checker can help you note what you're seeing.

When to see a vet

It's worth phoning your vet for advice for any cat with flu-like signs, especially kittens, older cats and cats with other health conditions.

Contact a vet urgently if your cat:

• has difficulty breathing, is breathing with their mouth open, or is breathing fast or noisily
• hasn't eaten for a day, or for less time in a kitten. Cats who go without food can become seriously unwell, so don't wait for the appetite to come back on its own. Our article on why a cat may stop eating explains why this matters
• is not drinking, or seems dehydrated
• is very lethargic, weak or collapses
• has a sore, cloudy or badly swollen eye, or is holding an eye closed
• is a young kitten showing any signs of illness

How vets diagnose it

Vets usually diagnose cat flu from the typical signs and a physical examination. They'll check temperature, look in the eyes, nose and mouth for discharge and ulcers, listen to the chest and assess hydration.

In many cases no further tests are needed. However, your vet may suggest swabs from the eyes, nose or mouth to identify which virus or bacteria is involved. This can be helpful if your cat is very poorly, isn't improving, has repeated episodes, or lives with other cats, for example in a breeding or rescue setting. If signs are severe or unusual, your vet may also recommend blood tests or tests for other infections such as FIV and FeLV, which can weaken the immune system.

Treatment and management

There's no medicine that simply switches off cat flu viruses, so treatment mostly focuses on supporting your cat while their immune system fights the infection. Depending on your cat's needs, your vet may:

• prescribe treatment for secondary bacterial infections
• give eye treatments if the eyes are affected
• offer pain relief for mouth ulcers or a sore throat
• give fluids if your cat is dehydrated
• in some cases, prescribe antiviral treatment
• admit very poorly cats to hospital for intensive nursing, fluids or assisted feeding

Never give your cat human cold or flu remedies or painkillers. Many are poisonous to cats.

Supportive care at home

Good nursing makes a real difference. Your vet may suggest:

• Gently cleaning the eyes and nose. Use cotton wool dampened with cooled boiled water, a fresh piece for each eye, and wipe away discharge softly. This helps your cat breathe and feel more comfortable.
• Encouraging eating. Warm wet food slightly to body temperature, as warmth releases smell. Strong-smelling foods, such as fishy varieties, may tempt a cat with a blocked nose. If mouth ulcers are present, soft food is easier. Offer small amounts often, and let your vet know if your cat still won't eat.
• Steam. Sitting with your cat in a steamy bathroom (never in the shower itself) for a few minutes can help loosen mucus. Your vet may also suggest other ways to help with congestion.
• Fresh water. Keep clean water close by, and make sure your cat is drinking.
• Rest and warmth. Provide a quiet, warm, cosy bed away from other pets and busy areas.
• Hygiene. Keep a sick cat away from other cats, use separate bowls and litter trays and wash your hands after handling them.

Most cats with uncomplicated flu start to improve within a couple of weeks, but recovery can take longer, and some cats are left with a long-term snuffly nose or sore eyes.

Prevention

• Vaccination. Core vaccinations for cats usually include protection against the main cat flu viruses. Vaccination doesn't always stop a cat from catching flu, but it tends to make illness much milder. Talk to your vet about the right schedule for your kitten or adult cat, including boosters.
• Isolate new or sick cats. Keep new arrivals, and any cat showing signs, separate from others for a while.
• Good hygiene. Clean bowls, bedding and litter trays regularly, and wash your hands between handling different cats.
• Reduce stress. For carrier cats, keeping routines steady may help limit flare-ups.
• Choose catteries carefully. Reputable catteries require up-to-date vaccinations.

Living with it

If your cat is a carrier or has occasional flare-ups, you may notice mild signs during stressful periods, such as a house move, a new pet or a cattery stay. Knowing this helps you act early: keep their eyes and nose clean, tempt them with warm food and call your vet if they stop eating or seem unwell. With good care, most cats with a history of cat flu live happy, normal lives.