Feline leukaemia virus

Cat asleep on sofa with knitted blanket and wool
Written by: Sam Webster (BVetMed MRCVS) Head Vet at Joii

Feline leukaemia virus (FeLV) is a viral infection that affects cats and is unfortunately incurable and eventually fatal.

This disease only affects cats and cannot be passed onto people, dogs or other animals, but it can be transmitted to other cats through saliva, blood and sometimes through urine and poo. Whilst the virus is incurable, there are certain things you can do to keep your cat safe and prevent them from catching this disease.

In this short guide, we’ll look into what the virus is, the signs and symptoms to look out for, how to treat a cat with the disease and preventative measures to keep your feline friend safe.

What is feline leukaemia virus?


Feline leukaemia virus, otherwise known as FeLV, is an incurable virus that causes a fatal disease by stopping a cat’s immune system from working properly. It can also put them more at risk of catching other infections and developing cancers.

Vaccinating against the virus can be one way of preventing the disease, but this usually depends on where you live and your cat’s lifestyle. For example, a cat who lives entirely indoors in a single cat household probably wouldn’t need a vaccination. Cats usually catch this virus through direct contact with the saliva of infected cats, or through grooming or sharing food and/or water bowls. An infected pregnant queen will also pass the virus onto her kittens.

Symptoms of feline leukaemia virus


Signs and symptoms of feline leukaemia virus can develop over months or even years and can sometimes be mistaken for other infections. However, the main symptoms of FeLV include:

  • Progressive weight loss
  • Reduced appetite
  • Tiredness and weakness
  • Pale gums
  • Fever
  • Enlarged lymph nodes
  • Poor coat condition
  • Persistent diarrhoea
  • Inflammation of the gums and mouth
  • Bladder, skin or upper respiratory infections


The effect this virus has on the immune system in particular can actually cause cancer, which is why it’s called feline leukaemia virus. Your vet can diagnose this condition by taking a blood test from your cat.



How to treat feline leukaemia virus


Once a cat is infected with FeLV, there is unfortunately no cure. Whilst there is no way of  predicting exactly how long they will live, it’s likely their lifespan will be shortened.


If your cat has been diagnosed with feline leukaemia virus, they should be kept indoors to prevent them from spreading the virus and to stop them from being exposed to infections. You should also cut out any foods that could carry bacteria such as raw meat or eggs.


Your vet may recommend supportive treatments, such as antibiotic courses to tackle any bacterial infections, antiviral medications, and there may be cancer treatments available if your vet feels they would help.


Vaccinations can help to prevent feline leukaemia virus and are routinely recommended in all cats going outdoors. For further information on vaccinations it is advised to talk to your vet.


Don’t forget to check out Asda Pet Insurance to see how you can be protected against those unexpected vets bills and costly treatments. You’ll also get access to a 24-hour Vet Advice Line to get help with everyday health issues and concerns.

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