Feline Leukemia: Causes, Symptoms and Treatments

Authored byVeronic Fournier


If you are a cat owner, you are probably familiar with the feline leukemia virus, either directly or indirectly.


In fact, when we talk about feline leukemia, it’s mostly about FeLV virus rather than blood cancer. That said, this virus has the insidious power to cause cancer. I therefore invite you to consult our complete guide to cat cancer for more details on this subject.


The feline leukemia virus is easily transmitted between cats in a number of ways. It can cause a host of symptoms that can be life threatening to a kitty cat.



In my career as an animal health technician, I have cared for several stray cats and these cats frequently tested positive for this virus.


Read on to learn about the different forms of this disease, its symptoms and the treatments to consider for an affected cat. See everything you need to know about feline leukemia below.


Please refer to our complete guide to cat cancer to learn more about the various cancers affecting dogs.



What is leukemia in cats?


Feline leukemia (FeLV) is one of the most common infectious diseases in domestic cats. It affects around 3% of the feline population in Europe and more than 20% of cats considered at risk (cats that go outside without supervision, those in direct contact with an infected cat and kittens born to an affected mother).



What causes leukemia in cats?


As mentioned above, feline leukemia (FeLV) is caused by a retrovirus, a virus from the same family as HIV. Fortunately, fewer and fewer cats are affected by this disease, as a vaccine for the virus is now available.



What is the difference between Feline Leukemia Virus and Leukemia Cancer (Blood Cancer) in cats?


Most often, when we refer to leukemia virus in cats, we are talking about the FeLV virus described throughout this article. This virus is, however, the main cause of blood cancer (lymphoblastic leukemia) in our kitties. The latter gradually destroys the immune system of the affected cat and compromises its ability to form new healthy blood cells.



What are the symptoms of the feline leukemia virus?


In the early stages of infection, it’s common for cats to show little or no symptoms of feline leukemia. Depending on the individual, the signs will start to appear after a few weeks, months or years. Among its symptoms, we can find:

  • Decreased appetite
  • Gradual weight loss
  • Poor coat quality
  • Enlarged lymph nodes
  • Fever
  • Pale mucous membranes (gums)
  • Inflammation of the gums (severe gingivitis) and mouth (stomatitis)
  • Frequent secondary infections: skin infection, abscess, urinary tract infection, upper respiratory tract infection and / or eye infection (an episode of rhinotracheitis or cat flu)
  • Chronic diarrhea
  • Epileptic attacks, behavioral changes or other neurological conditions
  • Miscarriage or other reproductive harm



The stages of feline leukemia and their life expectancy


A cat that comes in contact with the cat leukemia virus is not necessarily doomed. The immune system of an exposed cat can respond in different ways. These are described below.


Neutralization of the virus


Fortunately, some cats are able to fight the virus! Their immune system quickly gets rid of the virus and the animal then develops immune defenses against the disease. The life expectancy of these cats therefore remains the same as for a cat that has never had contact with this disease.


Regressive infection


A regressive infection occurs when the virus replicates very little in the body. Few of the cells in the body are infected. These cats are not actively contagious, but could transmit the virus through a blood transfusion. These cats may appear normal for a while and may even be successful in getting rid of the virus completely.


Latent form


We talk about latent infection when a moderate number of cells in the body are infected. These cats are not contagious as long as the virus is latent (dormant).


On the other hand, the virus has the potential to "wake up" at any time when there is a collapse of the immune system or when the cat is under stress. Symptoms often appear when cats are young adults, between maturity and the age of 5.


Persistent viremia


Viremia occurs when the virus spreads in the blood. The virus is therefore actively excreted into the environment, via saliva amongst other things. This form of infection can be considered to be the final stage of feline leukemia.


Viremic cats have a weakened immune system. This makes them more at risk of secondary infections, and makes wound healing slower and more difficult. When this viremic phase persists, sick cats develop anemia (a red blood cell count that is too low) and lymphoma (lymphatic cancer).


The life expectancy of these cats is about 2 to 5 years after the initial infection, but rarely exceeds 3 years.



Is feline leukemia contagious?


The virus is not contagious to humans, but as you may understand, it is very contagious between cats. Cats that have a persistent form of feline leukemia are the source of contagion.


Here are the different modes of transmission of feline leukemia:

  • Saliva (main method of transmission)
  • Nasal secretions
  • Urine
  • Feces
  • Milk from an infected mother
  • Blood (bites, blood transfusions, via a contaminated instrument or needle)
  • Pregnancy (the mother can transmit the virus to her young)


How contagious is feline leukemia?


Sneezing, sharing litter between two cats at home, sharing bowls of food or water, and grooming between two cats are enough for transmission of the feline leukemia virus to occur.



Treatments for Feline Leukemia


There is no proper treatment for feline leukemia. Vets can only offer supportive treatments and treat secondary infections in cats showing active signs of the disease. But don’t give up hope!


Feline Leukemia Vaccine


Your vet will likely recommend that you vaccinate your young kitten against feline leukemia during their first checkup. This vaccine has proven its worth. That said, it’s worthwhile having your cat tested before vaccinating it, because if they are already a carrier of the virus, the vaccine will be useless.


As with any vaccine, there is always a risk of side effects. You must therefore consider the lifestyle of your cat to see if the vaccine is appropriate.



Natural product to help your feline in his fight of leukemia


PIPTOPET can be used to promote your cat's health even during the fight of cells affected by the virus, whether they are cancerous or not. This natural product can therefore help your pet even in the early stages of feline leukemia. As a pet parent, you want to prevent the development of cancer following infection with the virus.


SILVERPET is also a holistic tool to have in your arsenal against feline leukemia. This other natural product acts, among other things, as an antiviral and a natural antibiotic. It therefore helps maintain the body healthy. A healthy system fight viral particles, while protecting your pet against secondary infections.


Whether your cat has feline leukemia virus (FeLV) or blood cancer, this product works for both. It will greatly support your cat’s immune system.



Now that you are experts in the field of feline leukemia, you can keep an eye out for symptoms so that you are ready to act quickly.


Does your cat have feline leukemia? Contact our healthcare professionals for personalized recommendations. 


About the author

Veronic Fournier
Veronic Fournier


Véronique Fournier shares her extensive pet health know-how on Zumalka through her articles.

Véronique’s background as an animal wellness advocate began in Cégep La Pocatière in Quebec, which led to comprehensive internships and training with respect to the breeding, rehabilitation, and monitoring of various types of animals. The institutions she has worked with include the Quebec Aquarium and the SOS Miss Dolittle shelter, just to name a few.

Her immersion with various veterinary clinics in British Columbia and other places has made Veronique not just knowledgeable, but also quite perceptive in zeroing in on the right strategy to help keep pets in the best of health.

And can we get you in on a secret? Veronique shares that she has already made a lot of canine pals due to her stint as a foster mom in several shelters. Isn’t that cool?

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