Feline leukemia virus (FeLV) is a retrovirus that weakens a cat’s immune system. The name is a bit of a misnomer, since the disease more closely resembles HIV in humans than leukemia. Often called the “friendly cat” disease since it is spread through casual contact such as sharing food or water or grooming, FeLV is highly contagious and potentially fatal.

The risk of contracting FeLV exists for all cats, but certain factors such as age, lifestyle, gender and vaccination status can all affect how susceptible your cat might be to the disease. Those cats who spend unsupervised time outdoors, live in multi-cat households or who have not been spayed or neutered are among those at greater risk.

Cats who have been exposed to FeLV may or may not be infected. Adult cats must be exposed to large amounts of the virus in order to become infected. Prolonged exposure or a bite is usually necessary for transmission. Some cats may have inadequate exposure that allows their immune system to mount a successful response; others will develop a latent infection, meaning they are unable to completely rid themselves of the virus, but they aren’t contagious, either. Still other cats will develop a persistent infection. These are the cats who become contagious to other cats and who often develop diseases associated with FeLV within a few years.

So what should you watch for if you think your cat may have been infected? FeLV symptoms may include weight loss, a reduction in the effectiveness of the immune system, fever, anemia, respiratory and eye problems and oral disease. The first indication of infection in some cats is recurrent bacterial infections of the mouth.

Infection with FeLV is not a death sentence for your cat, but caring for a kitty with FeLV is more complicated than caring for a fully healthy cat. Cats with FeLV are also more susceptible to illnesses and secondary infections and are less able to fight them off because of their compromised immune systems. Supportive care and more frequent veterinary visits can help a cat with FeLV live to a ripe, old age.

There is a vaccine for FeLV, and we recommend vaccination based on certain risk factors. Not all cats should receive the FeLV vaccination, and those who do should be tested before vaccination to ensure they are not already infected. If you think your cat may need to be vaccinated against FeLV, please contact our office to schedule an appointment to discuss whether this option is right for you and your favorite feline.