Cat leukaemia: spotting the signs of feline leukaemia
First Published: 21/02/2019
Last Updated: 18/12/2024
Feline leukaemia virus (FeLV) is a contagious viral infection that targets your cat's immune system, causing a variety of symptoms and putting them at risk of other diseases. It's one of the most common infectious diseases cats are at risk from, and is also an important cause of cancer in cats.
After infection, the virus may progress gradually, with symptoms appearing over months or even years. Vaccination is crucial, as once a cat becomes persistently infected with feline leukaemia, it cannot be cured.
How is feline leukaemia transmitted?
Infected cats have large amounts of the virus in their saliva, and possibly also in the faeces, urine and milk. Once one cat is infected, the virus can spread through activities like mutual grooming, sharing of food bowls, and using the same litter trays. Biting can also spread FeLV, and an infected mother cat can pass it on to her kittens, either before birth or through nursing. The virus doesn't survive long outside the host, so it is less likely to spread from indirect environmental contact.
Younger cats and kittens are more vulnerable to FeLV because their immune systems are still developing. Outdoor cats or those living with other infected cats are also at higher risk. Any cat exposed to the virus can become infected, regardless of age, but those with weaker immune systems or who are not vaccinated are at the greatest risk.
FeLV infection outcomes
The virus can have varying outcomes in cats, depending on how their immune systems respond:
Abortive infection: the cat's immune system successfully eliminates the virus entirely before it becomes established, leading to complete immunity. Cats with an abortive infection will not test positive for FeLV and show no symptoms.
Regressive infection: the cat's immune system is keeping the virus under control, but cannot completely get rid of it. Cats with regressive infections won't show symptoms and rarely spread the disease, but the virus will become dangerous again if the cat's immune system weakens.
Progressive/persistent infection: active, ongoing infection with viral replication in the bone marrow and blood.
Cats with a progressive infection are likely to show clinical signs and are at high risk of transmitting the virus to other cats. Cats with progressive infections often have shorter life expectancies due to severe FeLV-related health issues.
What are the symptoms of feline leukaemia?
FeLV often progresses without visible signs in the initial stages. However, as the virus spreads and your cat's immune system becomes weaker, these symptoms may appear:
Weight loss: there may be loss of appetite, chronic weight loss and poor coat condition
Anaemia: this can be seen as pale gums, lethargy and weakness
Enlarged or swollen lymph nodes (also known as lymphadenopathy): enlarged glands can be felt as lumps in the neck, front of the chest of backs of the hindlegs
Recurring infections, such as respiratory, skin, or urinary tract infections
Chronic diarrhoea
Neurological symptoms: including gait changes, seizures or behavioural changes
Reproductive issues: miscarriage and pregnancy loss are common consequences in pregnant queens
Gingivitis and/or stomatitis: sore, inflamed gums and/or mouth is common
FeLV is a very serious condition, so if you notice any of these symptoms it is best to see a vet right away. FeLV is the leading cause of certain cancers in cats, so its advanced symptoms include lymphoma and some leukaemias.
How is FeLV diagnosed?
Diagnosing FeLV involves a blood test, which might be carried out because your vet suspects an infection due to symptoms, or just as part of a wellness screening. Two main types of tests are commonly used:
ELISA (enzyme-linked immunosorbent assay): This test can be carried out in your veterinary clinic. ELISA tests detect FeLV proteins in the blood, which can indicate active infection. The test is quick and easy, but false positives can occur, so sometimes a further test is done as confirmation.
IFA (indirect immunofluorescent antibody assay): This is an advanced test, usually conducted on a blood sample sent to a diagnostic laboratory. IFA tests are used to confirm FeLV infections, particularly for progressive cases. They detect viral particles within a cat's white blood cells, making it highly reliable for confirming the infection's persistence.
There's also PCR (polymerase chain reaction) tests which can detect regressive infections within the cat's genome, even if there are no active signs. Testing should ideally be repeated a few weeks after the initial test to confirm results, as some cats can initially test positive but later clear the infection.
What treatment options are available?
While there's no cure for FeLV, several treatments and management strategies can improve the quality of life for FeLV-positive cats. These mainly focus on managing symptoms and preventing secondary infections, which can severely impact a cat with a weakened immune system. Recommended treatment strategies include:
Medication: prompt diagnosis and treatment of secondary conditions such as skin and urine infections is necessary
Immune support: overall health should be monitored through regular health check-ups, and kept optimal through preventative care and high-quality nutrition
Symptom management: Appetite stimulants, anti-inflammatory medications, and – in severe cases – blood transfusions for anaemia may be necessary.
Stress minimisation: A cat's immune system can be upset by stress, so keeping their environment calm and surprise-free helps prevent FeLV progression.
Cats with FeLV should be kept strictly indoors to avoid exposure to other illnesses, as well as to protect other cats from infection. Having a check-up with the vet every six months will allow for monitoring any disease progression or onset of secondary infections.
Prevention and vaccination
Vaccination is the most effective way of preventing FeLV. Getting your cat vaccinated significantly reduces the risk of infection and is all the more important for multi-cat households and outdoor cats. Starter vaccinations courses typically begin when kittens are about eight or nine weeks old, and will include at least two doses of FeLV vaccine. Your cat will receive their first boosters one year after this course, and then another booster every three years after this. These vaccinations are all included within Pet Health Club membership.
Another important measure to take is having any new cats tested for FeLV before introducing them to your home, particularly if you have other cats. As mentioned earlier, a kitten can be infected right from birth if their mother had FeLV. Even in the case of a weeks-old kitten, testing could prevent the infection spreading among your other cats or other cats in your neighbourhood.
Read more: Kitten vaccination schedule
Making the adjustment to indoor life
For FeLV-positive cats accustomed to the outdoors, transitioning to an indoor lifestyle can be challenging but necessary. Here’s a few tips for making the transition smoother:
Secure the environment: Make sure windows are closed, block cat flaps, and remove potential escape routes.
Provide litter boxes: Ensure litter boxes are clean and placed in quiet, accessible areas.
Offer enrichment: Keep your cat engaged with toys, scratching posts, and interactive games to prevent boredom.
Create hiding spots: Set up comfortable spaces, like covered beds or high shelves, where your cat can retreat to feel safe.
Long-term prognosis for FeLV-positive cats
FeLV is a progressive condition, but in some cats the symptoms can be managed successfully for a reasonable period after diagnosis. However, on average, FeLV-positive cats live about 2-3 years after diagnosis, with some cats experiencing fewer symptoms and others needing more intensive care.
Early detection, a stable environment, regular vet check-ups, and prompt treatment of any secondary infections are the most important factors in helping a FeLV-positive cat live the best life possible.
Frequently asked questions about FeLV
Can my FeLV-positive cat live with other cats?
FeLV-positive cats can live safely with other FeLV-positive cats, but it's recommended to keep them separate from non-infected cats to reduce the risk of transmission. Although vaccination offers some protection, it doesn't fully prevent transmission between infected and non-infected cats.
How should I care for my FeLV-positive cat at home?
Keeping your FeLV-positive cat indoors and isolated from other cats is crucial. This is not just to protect the other cats (although this is very important), but also to make sure your cat doesn’t catch any other infections from them which their weakened immune system may not be able to handle. A balanced diet, regular vet visits, and prompt treatment for any infections are key. Minimising stress, maintaining a calm environment, and providing regular enrichment activities will help your cat remain comfortable and healthy for as long as possible.
Sources
Cornell University - Feline Leukaemia