Learning about Feline Leukemia Virus (FeLV)

This week let’s take a moment to discuss Feline Leukemia Virus, or FeLV.

It is one of the most common feline diseases and every cat owner should know what it is, how to look for it, how to treat it, and how to protect their cats from it.

This is a highly contagious virus that is passed from cat to cat through bodily fluids like saliva and affects roughly 2-3% of all cats in the United States. That number has decreased significantly with the development of more accurate tests and vaccines, but it is still very possible for a cat to become infected with FeLV especially if they go outside at all and interact with other cats. The scary part of FeLV is that there is currently no true cure.

If you suspect your cat has FeLV or could have even been exposed to it by other cats, take your cat to the vet right away. The vet should perform at least two separate tests to avoid any possibility of a false positive and ensure FeLV is present.

If your cat has tested positive there are a few treatment options. There are some feline therapies available to decrease the disease, but these come with significant side effects and can not truly eliminate FeLV. The most common treatment plan involves watching your cat for specific problems and treating those separately. For example, if the cat has an infection due to the weakened immune system then the vet can prescribe antibiotics for the infection.

While this is an intense disease do not despair for your cat. If you maintain bi-yearly vet visit and are vigilant about their condition, your kitty can lead a good life. There are three possible stages or outcomes of FeLV viral infections. They are Abortive stage, Regressive stage, and Progressive stage.

The Abortive stage refers to a cat who catches FeLV but clears the infection and becomes immune. 70% of all FeLV adult cats end up with this outcome. At this stage they no longer pose a threat to infecting other cats around them and they will live a happy, healthy life with no more problems from FeLV.

The next two we’ll put into a human prospective.  Think of FeLV like AIDS in people.  The patient contracts HIV (Regressive stage). They may not be sick, but they carry the disease and can pass it on to others. The Regressive stage refers to a cat who catches FeLV but has no symptoms and doesn’t truly become ill. The hiccup though is that the FeLV virus integrates itself into the cat’s genes becoming a latent infection. Regressive cats are immune to the virus themselves but do pose a threat to other cats around them and could potentially transmit the virus.

The Progressive stage is like having AIDS in humans.  The cat has signs, symptoms and illness. The cat that has persistent infection and diseases from FeLV and is highly contagious to other cats. This cat can transmit the virus in their bodily fluids and through close contact with other cats, but mostly through deep bites which is why it is contracted more often in outside feral cats defending their territory. Eventually, the virus moves into the bone marrow of the host cat within two or three years. The survival rate of progressive cats is about three years after a confirmed positive diagnosis, BUT an indoor only cat could potentially live longer with a good quality of life through careful monitoring of weight, appetite, mouth and eye’s appearances, and behavior.

As with AIDS, FeLV doesn’t kill, it’s the infections they receive due to the depleted immune system caused by FeLV.

Symptoms of FeLV can include:

  • Severe anemia
  • Suppressed immune system
  • Loss of appetite
  • Progressive weight loss
  • Poor coat condition
  • Persistent fever
  • Inflamed and pale gums
  • Diarrhea
  • Seizures
  • Behavior changes
  • Serious eye conditions

Before ever being introduced into a new household, all cats should be screened for FeLV. Cats who spend any time outdoors should be tested for FeLV yearly by the Veterinarian. The test, also referred to as a “snap test”, is very easy to perform, requiring only a few drops of blood.

To protect your furry loved one, the best course of action is to prevent exposure from infected cats by keeping them indoors as well as supervising the cat if it goes outside. If you have an infected cat, they should be separated from the rest of the cats and always have a separate food bowl and litter box. If you do have a positive cat and would like more, check out local animal rescues or shelters.  Getting other positive kitties will not worsen their condition and will make for great companions.

Keeping a look out for symptoms and regular visits to the vet will make sure your cat stays healthy and strong!



Olah, Glenn. (2018, May 11). Living with FeLV-infected cats: A guide for veterinarians and their clients. Retrieved on February 24, 2019 from http://veterinarynews.dvm360.com/living-with-felv-infected-cats-guide-veterinarians-and-their-clients

Alley Cat Allies. (2019). Feline Leukemia Virus (FeLV). Retrieved on February 24, 2019 from https://www.alleycat.org/resources/feline-leukemia-virus-felv/

Kornreich, Dr. Bruce. (2016). Feline Leukemia Virus. Retrieved on February 24, 2019 from https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-leukemia-virus

Written By: Mikayla B.  AZ CARE Rescue Intern (March. 2019)

Leave a Reply

Your email address will not be published.