Feline Leukemia Virus (FeLV)

FeLV is a disease that reduces the immune system's ability to protect itself against secondary infections caused by common bacteria, viruses, protozoa and fungi. FeLV infection occurs worldwide, with prevalence varying by location.1 FeLV is transmitted through casual contact such as mutual grooming and sharing of food/water bowls and litter boxes, and can also be spread through bite wounds. While all cats can get FeLV, outdoor and intact male cats have a higher risk of infection due to an increased chance of contact with other cats and fluid exchange through fighting. Under ideal conditions, with proper care, infected cats can appear relatively healthy for many months to even years after infection.

Signs of Possible Infection

Cats are experts at hiding disease. Early signs of infection are often subtle and frequently produce the observation "My cat simply isn't feeling well." These signs include decreased appetite, decreased grooming and low energy. Advanced infection may include:

  • Marked loss of appetite
  • Weight loss
  • Weakness
  • Pale gums
  • Mouth sores
  • Diarrhea
  • Enlarged lymph nodes
  • Abscesses

Cats often show no signs of infection, so it's important to ask your veterinarian about FeLV testing as part of your cat's annual wellness exam.


If you have an FeLV positive cat, you should visit your vet twice a year to track your cat's progress, and make sure your cat is getting the proper nutrition. Keep your cat indoors and isolated from other cats in the household to greatly reduce the chance of a secondary illness. Spaying or neutering your cat will also reduce the tendency for your cat to fight and/or mate, thereby decreasing the ability to spread the virus.

See your vet immediately if there are any signs of illness. Keeping your cat inside and away from other cats in the house can greatly reduce the chance of a secondary illness as well as spreading the disease to other cats.


If your cat displays these signs and you think your cat may have the disease, see your veterinarian. He or she will check the cat's history, look for clinical signs, and possibly administer a blood test for FeLV antigens. FeLV affects 2-3% of cats nationwide; testing for infection is easy. Testing identifies those cats that must be kept isolated from other cats in order to curb the spread of the infection. There are tests that can be performed right in your vet's office with results in minutes, allowing you to consult with your vet before leaving. Early detection will help you maintain the health of your cat and prevent spreading infection to other cats. With proper care, infected cats can appear relatively healthy for many months to even years after infection.

The American Association of Feline Practitioners (AAFP), an organization of veterinarians with a special interest in the health of cats, urges you to have your cat tested for FeLV. Infected cats can live for years if diagnosed early and treated properly.

1 Levy JK, Ettinger SJ, Feldman EC, eds. Textbook of Veterinary Internal Medicine. Philadelphia, PA: WB Saunders; 2000:424-432.

Q. How is FeLV spread?

A. FeLV is primarily spread through casual contact such as mutual grooming, sharing food/water bowls and litter boxes

Q. Can an infected mother give FeLV to her kittens?

A. Infected mothers can pass the virus to their offspring, either before birth or through nursing.

Q. Can I get FeLV from my pet?

A. No, FeLV only infects cats and cannot be transmitted from your pet to you or your family.

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