Is Feline Leukemia A Cancer Or A Virus, And Is It Contagious?

Feline Leukemia is often a confusing subject because of its name. In humans, leukemia is a type of cancer of the blood and bone marrow, but in cats leukemia is actually a virus. However, it can also lead to cancer in cats. It’s important to understand feline leukemia because it’s highly contagious and is one of the most common infectious diseases in cats, and it can be fatal.

There are actually three types of feline leukemia virus (FeLV). All cats infected with the virus test positive for FeLV-A, which is the virus that makes the disease so dangerous since it suppresses the immune system. About half of infected cats also have FeLV-B, which causes abnormal tissue growth and tumors. And FeLV-C is the third and rarest type that affects only a small percent of infected cats, causing severe anemia. Cats that test positive for feline leukemia can have one, two, or all three types of the virus.

Feline leukemia is highly contagious. In fact, it’s sometimes referred to as the “friendly cat” disease since it’s easily spread from cat to cat through contact that shares saliva or nasal secretions, such as grooming or biting. Cats are at a greater risk of FeLV infection if they come into close contact with other infected cats either within the home or while outdoors. Kittens born to infected mothers are also at greater risk, as are kittens that are born from healthy mothers but are exposed through other infected cats.

The major risk of feline leukemia virus (FeLV) is that it weakens the immune system, which increases the risk of illness and developing a secondary infection. About a third of cats with FeLV develop a virus-related cancer, most commonly lymphoma or, less commonly leukemia.

Cats that have been infected by the feline leukemia virus commonly show no or few symptoms in the early stages of the disease. But over time—weeks, months, or sometimes even years—symptoms progress. The most common symptoms of feline leukemia include:

  • Lethargy
  • Loss of appetite, weight loss
  • Anemia
  • Abscesses or sores
  • Swollen lymph nodes
  • Diarrhea or vomiting
  • Fever
  • Skin infections and poor coat condition
  • Wobbly, unsteady gait or movement
  • Runny nose, inflammation of gums and/or mouth tissue
  • Lymphoma (cancer that develops from FeLV)
  • Fibrosarcomas (cancer that develops from fibrous tissue)

A simple blood test by your vet can indicate whether or not you cat has the feline leukemia virus. While there’s no definitive cure, vets can treat infected cats for symptoms as they occur, such as prescribing antibiotics for bacterial infections, or giving blood transfusions for severe anemia, for example.

Fortunately, vaccinations against the feline leukemia virus are safe and effective, and can help you prevent your cat from developing the disease. PetWellClinic® can help you determine your cat’s risk for exposure to feline leukemia, and how the FeLV vaccination may protect your cat should unexpected exposure occur. We also offer low-cost kitten and cat packages that include all the necessary vaccinations your cat needs for a healthy, long life.

By operating convenient hours for non-surgical care, PetWellClinic® is able to offer substantially discounted prices for vaccinations, safe and effective flea and tick preventative products, wellness exams, and treatment of minor conditions—with quick in-and-out service during convenient evening and weekend hours with no appointment necessary. To see how we’re able to offer more affordable pet care without compromising quality, check out our free and quick guidebook to how PetWellClinic® can save you time and money.

PetWellClinic® has three locations: 10549 Kingston Pike, Knoxville, TN 37922; 7329 Kingston Pike, Knoxville, TN 37919; and 228 S. Calderwood Street, Alcoa, TN 37701. Learn more about how PetWellClinic® can exceed your expectations for top quality, affordable pet care by visiting our website at


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