Feline Leukemia Virus and Your Cat

By Lorie Huston, DVM on Feb. 4, 2013

Feline leukemia is a concern for many cat owners. It seems most cat owners have heard of the disease but many do not fully understand how their cat can get feline leukemia or how it can affect their cat. Let’s talk a little bit about that.

What Is Feline Leukemia?

Feline leukemia is caused by a virus known as the feline leukemia virus, or FeLV. It is a contagious disease that can be passed from cat to cat through direct contact. Usually close contact with an infected cat is necessary for transmission of the virus. Casual contact is not typically dangerous. The virus can also be passed from a mother cat to her kittens.


What Kinds of Symptoms Are Seen with Feline Leukemia?

Some cats infected with feline leukemia will show no signs at all. When symptoms do occur, they can appear in almost any form. Common symptoms include lack of appetite, lethargy, fever, and weight loss. Respiratory symptoms such as coughing, sneezing, runny eyes, or a runny nose may be seen. Diarrhea and/or vomiting may be present. Some cats may be icteric (have yellow coloration in their skin and gums). Other symptoms may develop as well.

Essentially, any sick cat with an unknown feline leukemia virus status could be suffering from feline leukemia and testing should be performed to rule out the infection.

How Can I Tell If My Cat Has Feline Leukemia?

Blood testing is the only way to tell whether your cat is infected with the feline leukemia virus. A screening test requires only a few drops of your cat’s blood and usually can be performed in a matter of minutes. If the screening test is positive, your veterinarian may recommend further blood testing to confirm the diagnosis.

It’s a good idea for all cats to be tested for feline leukemia. Without a blood test, it is impossible to determine whether a cat is infected with FeLV. Seemingly healthy cats can test positive for the virus.

What If My Cat Does Test Positive for FeLV?

Knowing your cat’s feline leukemia virus status can ensure that adequate steps are taken to protect your cat’s health as well as the health of other cats. An otherwise healthy cat that tests positive for FeLV does not need to euthanized. However, it is important that positive cats be housed indoors. If positive, your cat should be kept current on core vaccinations such as rabies, feline panleukopenia, feline calicivirus, and feline rhinotracheitis. Take steps to keep your cat parasite-free. Avoid feeding raw food. Seek veterinary care immediately if your FeLV positive cat is not acting right.

How Can I Prevent My Cat from Getting This Disease?

There is a vaccination available that provides protection against feline leukemia. However, the vaccine is not a core vaccine and is not recommended for all cats. Only those cats whose lifestyle puts them at risk for infection should be vaccinated against FeLV. Cats that live indoors and are not exposed to other cats are not at risk for infection.

Some veterinarians do recommend vaccinating kittens against feline leukemia regardless of lifestyle because of the fact that kittens are more susceptible to infection than mature cats. However, this is not a universally accepted practice.

Dr. Lorie Huston

Image: Seiji / via Shutterstock


Lorie Huston, DVM


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