Feline Leukemia Virus (FeLV): What you need to know

Milo, a grey and white long-haired cat.

Have you ever visited one of Animal Humane Society’s adoption centers and seen a cat that was noted to have Feline Leukemia Virus (FeLV) and wondered what that meant?

What is Feline Leukemia Virus (FeLV)?

Feline Leukemia Virus is one of the most common infectious diseases in cats, affecting 2-3% of all cats in the U.S. The virus can cause cancer, blood disorders, and immune deficiency, which makes cats more susceptible to other infections.

Cats that test positive for FeLV tend to have shorter lifespans, however during the early stages of infection, cats may not display any symptoms. If provided proper care and management, many cats with FeLV live years in good health.

How do cats get FeLV?

FeLV is only contagious to cats and doesn’t affect people, dogs, or other animals. The virus is not persistent in the environment and typically only survives a couple hours outside a cat’s body.

The virus is typically transmitted through fighting, mutual grooming, playing, and rarely through shared litterboxes or bowls.

Newborn kitten being held.

An infected mother cat can also transmit the virus to her kittens before birth or while nursing. Studies have shown that kittens infected by their mother prior to birth may have a higher likelihood of clearing the virus (no longer having the virus in their body), however, it’s not possible to predict if a kitten will clear the virus.

There’s no cure for FeLV, but there is a preventative vaccine if your cat is more likely to be exposed to the virus. The only completely effective method of protecting cats from FeLV is to prevent exposure to cats who are positive for the virus.

If your cat is allowed outdoors, supervise them, or consider building a catio so your cat can enjoy being outside without risk of them wandering or encountering other cats.

Adopting a cat with FeLV

Many cats with FeLV have a good quality of life and can live many years in good health if the virus and their symptoms are managed well.

Because FeLV is contagious to other cats, we recommend these cats go to homes where they’ll be the only cat or to a home that already has a cat with FeLV.

Adopters of a cat with FeLV may have additional veterinary expenses as the virus progresses because of their kitty’s suppressed immune system, but it varies case by case. 

Grey and white cat getting head scratches.

Signs of the virus progressing can include:

  • Loss of appetite

  • Weight loss
  • Poor coat condition
  • Enlarged lymph nodes
  • Fever
  • Diarrhea
  • Pale gums
  • Gingivitis or stomatitis
  • Skin, bladder, and upper respiratory infections
  • Eye conditions
  • Neurological disorders

On the fence about adopting a cat with FeLV? Dr. Sara Lewis, Managing Shelter Veterinarian at AHS, says, “Cats with FeLV have just as much love to give as any other cat. While it’s important to consider the additional expenses and impacts FeLV can bring, I encourage potential adopters to give these kitties a chance. Some of my favorite cats at AHS have been cats diagnosed with FeLV!”

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