Feline Leukemia

Feline leukemia virus suppresses a cat’s immune system and increases their risk of infection, anemia and cancer. Cats are more likely to become infected when they are young, but may not show signs for years.

Transfer of the virus can occur from mother cats to kittens, between cats that live together, or between outdoor cats or cat colonies. The virus is transmitted through body fluid, so sharing food and water bowls, mutual grooming, fighting, and shared litter boxes can all provide an opportunity for virus transfer. Feline leukemia virus cannot live outside of a cat for very long and cleaning dishes, or contaminated surfaces can remove the virus.

It is always recommended, when introducing a new cat to the household, to quarantine that cat until they have been tested for feline leukemia virus. Your veterinarian in the hospital can run this test as part of the cat’s wellness exam. Cats like to be gradually introduced to each other in any case and can carry other contagious diseases, such as upper respiratory infections. For all of these reasons, it is a good idea to have one part of the home blocked off as a private space for the new cat.

There is a vaccine for feline leukemia virus. It is recommended to test your new cat for the virus and vaccinate if they are negative. Your cat’s vaccine protocol will depend on their lifestyle. Cats should be vaccinated against feline leukemia if they will be outdoors, or if they will be living in an environment where cats of unknown status will be coming in, such as foster homes or a home that feeds stray cats. An indoor cat that lives with an outdoor cat should also be vaccinated. Some veterinary sources recommend vaccinating kittens regardless of whether they will remain indoor cats, but not keeping up with the vaccine later in life.

The initial vaccine can be given at eight weeks of age, with a booster 3 to 4 weeks later. Another booster is administered 12 months later, and the vaccine is due again every 12 months. This can be coupled with your cat’s yearly exam.

There is no cure for feline leukemia, and there is no treatment for the virus in infected cats. Supportive care is provided for cats as symptoms occur.

Cats with feline leukemia can live happy lives as indoor cats, in a low-stress environment. It is important not to expose them to cats that may transmit other diseases since the virus suppresses the infected cat’s immune system. Keeping them indoors keeps them safe from other infections and keeps them from spreading feline leukemia to other cats.

It is important for you and your veterinarian to know your cat’s feline leukemia status and it will impact later treatment plans and may change the vaccination plans for your cat.

For more information:

  1. Pet Coach 
  2. Cornell University College of Veterinary Medicine

Written by Baleigh McWade, RVT