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kitten on a sofa showing cat flu symptoms

Cat flu symptoms, treatment and prevention

What is cat flu? 

Cat flu, also known as feline influenza or feline upper respiratory infection, is a common illness that affects the upper respiratory tract (nose, mouth, and throat) of cats. It’s mostly caused by two common viruses, and leads to symptoms similar to human flu. It's treatable in most cases, and there is a cat flu vaccine, but chronic infection with regular acute flare-ups is common. 

In some cases, it can be severe, and even fatal. Kittens are especially susceptible to severe flu, due to their immature immune systems. Elderly and immunosuppressed cats are also vulnerable, alongside the unvaccinated cat population.

What are cat flu symptoms? 

There are many symptoms, and while your cat may not show signs of all of them, the most common are: 

In severe cases, your cat or kitten may have ulceration to the eyes, mouth and throat. 

If these symptoms become severe and aren't treated quickly enough, there can be severe consequences, such as permanent eye damage, pneumonia, and even death.  

cat showing feline influenza symptoms

If you think your cat or kitten is experiencing any of these symptoms, however mild, then contact your vet for advice and guidance. 

Kitten flu 

Upper respiratory infection in kittens can be particularly dangerous because of their underdeveloped immune system. This means that their symptoms may be more severe, and they could have a more challenging recovery. If your kitten has flu, they may suffer from more extreme symptoms such as: 

  • Ulcers 

  • Lung infections 

  • Breathing difficulties 

If you think your kitten has flu, call your vet immediately. You may need to bring your kitten in for observation. Your vet can offer expert advice on helping their recovery, such as ensuring your kitten is kept warm and hydrated, and assisting feeding. 

What causes cat flu? 

Most cases of are caused by infection with one or both of the feline influenza viruses.  

Both viruses are highly contagious and are easily caught. Once infected, cats can shed the virus for weeks, even if not displaying symptoms. 

These viruses are the cause of the vast majority of cases. However, there can be involvement of two other micro-organisms: 

  • Bordetella bronchiseptica 

  • Chlamydophila felis 

How is cat flu spread? 

Feline herpesvirus and feline calicivirus, the major causes of feline flu, are both highly contagious. They can be spread by cats through direct or indirect transmission.  

Direct transmission means your cat or kitten has come into contact with a cat with either of the two viruses. The infected cat will secrete the virus through their saliva, tears or nasal mucus. This can then be transferred to another cat through sneezing, mutual grooming, fighting or mating.  

Cats can also carry FHV and FCV without displaying symptoms. Contact with these carrier cats can also lead to active infection in your cat.  

Indirect transmission occurs because the virus particles can live in the environment for a few days: around 2 days for FHV and 10 days for FCV. So, for example, they could be on food bowls, bedding, or toys. This way, your cat wouldn't have to be in contact with the infected cat, only be around anything they may have used or touched because of how contagious the viruses are. 

How long is the feline influenza incubation period? 

Feline flu has an incubation period of around two to 10 days. This means that your cat may be infected before they begin to show symptoms. As soon as symptoms arise, call your vet and isolate your cat to reduce the risk of transmission. 

Cat flu treatment 

There is no cure for kitten flu, so treatment is aimed at countering the clinical signs until your cat's immune system can fight off the infection.

The mainstays of supportive care include warmth, assisted feeding, hydration and general nursing care, such as keeping weepy eyes clean. Make sure your cat has a warm and comfortable place to rest, and offer them food and water frequently. Keep a close eye on whether they are eating or not, as affected cats often lose their appetite. If your cat is very congested, taking them into a warm, steamy room can help.

Lack of appetite is a real concern in these cases. Strong-smelling, wet foods can help them maintain an appetite, especially if your kitten is suffering from a sore throat and blocked nose. If your cat cannot be tempted to eat, your vet may need to place a feeding tube. If they are also not maintaining their fluids, they may require an intravenous drip. Eye drops may be required for cases with severe conjunctivitis

cat flu treatment eye drops

In cases where secondary bacterial infection is suspected, your vet may prescribe antibiotics. Once the delicate lining of the nose and mouth has been damaged, bacterial infections are a common complication. Pain medications may also be prescribed to alleviate discomfort, but these should only ever be prescribed by your vet. Never give your cat pain relief unless specifically told to by your vet.  

In severe cases, antiviral drugs such as famciclovir may be prescribed, particularly in cases of feline herpesvirus infection. Interferon treatment may also be considered - these are proteins which help the body to fight viral infections.  

How is feline influenza diagnosed? 

Feline flu is generally diagnosed based on symptoms and a physical examination by a vet. Occasionally, a swab may be taken from the eyes, mouth or nose and sent to a laboratory for culture.  

How can feline influenza be prevented? 

Vaccination significantly reduces the risk. Cats that get the feline influenza vaccine are not completely immune to flu, but tend to have much milder symptoms if they do contract one of the viruses. Your kitten’s primary vaccination course includes the herpesvirus and calicivirus vaccinations.  

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This primary course should be given between six and eight weeks with a booster between 10 and 12 and 14 and 16 weeks. Once the primary course is finished, your cat usually receives a vaccine booster every year, although this is at your vet's discretion. Subscribing to a preventative healthcare plan, such as Pet Health Club™, will ensure your cat is always up to date with their vaccinations, leaving you with complete peace of mind. 

If you have a cat in the household with symptoms of flu, isolate them as much as possible from any other cats. Keep them inside, and use separate food bowls, water bowls and litter trays until they are recovered. You should make sure your hand hygiene is excellent after being with the affected cat. Both FHV and FCV are susceptible to most disinfectants, although these chemicals should be used carefully, as they can be an irritant to cats. 

Can feline influenza be fatal? 

The vast majority of cats who contract feline flu will make a full recovery. In rare cases, such as if your pet is unvaccinated or has other underlying conditions, they may develop severe complications, and this can lead to death. A proportion of cats will be left with chronic issues, such as long-term respiratory, nasal or eye disease, needing life-long medication. 

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Adopting a cat with feline influenza

Most cats infected with a feline flu virus recover well. However, some remain carriers, which means that they can potentially infect other cats. They may also have periodic resurgences of active, symptomatic flu, especially after stressful events such as a vet visit or cattery stay.  

It is perfectly possible to adopt a cat with feline flu, but some precautions must be taken. It is usually advised for cats who have had it to be homed as a single cat, or in a household with another flu carrier cat. If rehoming to a shared environment with a susceptible cat, the susceptible cat must be vaccinated and appropriate hygiene precautions taken. If you are considering rehoming a cat who has had feline flu, and you have other cats, discuss this with a veterinary surgeon first.  

Does my cat sneezing mean she has flu? 

Sneezing is a fairly common symptom in cats. The most likely cause is one of the feline flu viruses, but there are other reasons why your cat may be sneezing. Many diseases affecting the nose, pharynx (throat) and sinuses can cause sneezing, such as foreign objects (e.g. grass seeds), dental disease, tumours and allergies. If your cat is sneezing, always get advice from a vet.  

Can humans catch cat flu? 

The viruses which cause feline influenza do not affect humans. Your cat cannot transmit the flu to you, just as human flu cannot affect cats.  

How long does cat flu last? 

Symptoms should be improving by around seven days, and most cats are fully recovered within two to three weeks.  

Can cats get colds? 

The ‘common cold’ is a term which refers to a group of viruses which cause cold symptoms in humans. Cats cannot catch these cold viruses, however they are susceptible to two feline viruses (feline herpesvirus and feline calicivirus) which cause cold-like symptoms. This condition is usually referred to as feline influenza.  

Do cat colds go away on their own? 

Feline influenza, causing similar symptoms in cats to a cold in humans, usually resolves in healthy cats within a few weeks. Cats with cold symptoms such as a runny nose, sneezing, lethargy and discharge from the eyes may need some nursing care such as tempting them to eat and drink, and carefully wiping away discharges. If your cat seems unwell with a cold, then take them to a vet for a check-up. Some cats can become very unwell with flu and need veterinary care.  

six month health checks for cats after the cat flu vaccine