Pet health library

Feline leukemia: what to know

Feline leukemia virus is one of the most significant infectious diseases in cats. The good news: testing and vaccination make it very manageable to prevent.

Feline leukemia virus (FeLV) affects a cat's immune system and can lead to anemia, infections and certain cancers over time. It's contagious between cats, but it is not a risk to people or dogs.

How it spreads

FeLV passes between cats through close, prolonged contact - shared food and water bowls, mutual grooming, bite wounds, and from a mother cat to her kittens. Outdoor cats, cats in multi-cat homes, and any cat that mingles with unknown cats are at higher risk.

Testing and prevention

A simple in-house blood test tells us a cat's FeLV status, and we recommend testing new cats and kittens before introducing them to other cats. For cats with any exposure risk, the FeLV vaccine offers strong protection.

Cats who test positive can still live good lives with attentive care - regular check-ups, keeping them indoors, and prompt attention to any illness all help. We'll build a plan that fits your cat's situation.

Good to know

Common questions

Does my indoor-only cat need the FeLV vaccine?
A strictly indoor cat with no exposure to other cats is at low risk, so we tailor the recommendation to your cat's lifestyle. If your cat goes outdoors, lives with other cats, or you plan to adopt another cat, vaccination is worth discussing.
Can a cat with feline leukemia live a normal life?
Many FeLV-positive cats live comfortably for years with good care. Keeping them indoors, staying current on wellness visits, and treating illnesses promptly all make a real difference.

Questions? Call your Fort Collins vet.