What to Know About Feline leukemia

By: Trupanion Staff / Updated May 29, 2018

Feline leukemia virus (FeLV) is a virus that can be transmitted between cats via saliva. It’s a tragic and fatal disease that is responsible for many cat deaths worldwide every year. More than 50% of cats infected with feline leukemia die within 2-3 years.  Most deaths in cats occur in the first year after diagnosis.

It’s important to be aware that FeLV is contagious and can be spread from animal to animal. The good news is that 72% of cats in multi-cat households (and 97% in single cat households) can fight and overcome the virus without any help.

What is Feline Leukemia Virus (FeLV)?

Despite the name, feline leukemia is not a form of cancer at all, but it can cause cancer. It’s a virus, present in around 2-3 percent of cats across the US. While that might seem like a small portion of the population the rate at which this disease spreads means that it is still a very real threat to all cat owners.

FeLV can cause cancer which makes it even more dangerous. There are several subgroups of FeLV. These subgroups are:

• FeLV-A
• FeLV-B
• FeLV-C
• FeLV-T

FeLV-A is the only one transmitted from cat to cat.  Some cats only carry FeLV-A, but others can carry any combination.  FeLV-B is associated with development of abnormal tissue or tumors. FeLV-C causes severe anemia and FeLV-T causes a suppressed or weakened immune system in cats.

As well as the different subgroups, feline leukemia also proceeds through stages. There are six stages in total. The virus enters the cat and spreads through the body, traveling through the bloodstream and replicating. Many cats are able to fight off the virus at this stage.  If the virus is not stopped, the bone marrow becomes infected. Once established in the bone marrow infected cells can be released. Lastly the virus is shed and can infect other cats.

How is FeLV diagnosed in cats?

There are several tests that can determine whether a cat is infected with feline leukemia. One test called ELISA looks for the virus in the blood. This test will determine whether the cat has the virus but not at what stage. It’s possible to test positive on this test and find that the virus hasn’t infected the bone marrow. This means that the cat could still fight the virus off themselves.

Be aware though that false positives and negatives are common. As such, if positive, a second test will usually be completed about twelve weeks after the first.

How do cats get FeLV?

As already mentioned, this virus is highly contagious. Cats can pick up the virus from saliva, urine, feces, nasal secretions, and milk of an infected cat. Sadly, kittens can also contract it in the womb from their infected mother. While most kittens will die before birth, some die a short time after birth or will survive and remain infected.

Social behaviors such as grooming, biting or sharing food areas can also cause transmission of feline leukemia. Ultimately, close proximity is required. The virus will not survive in the environment for very long at all.

Is there a cure?

Unfortunately, there is no cure for feline leukemia, and the cat’s life will typically be shortened due to it. However, how much the disease will impact the cat is hard to predict. Some will live with the condition for years. Once a cat becomes infected, it must be kept separate from other cats. It cannot be allowed to wander freely outside and should stay inside the house.

While there is no cure, there are multiple ways that you can prolong a cat’s chances when they have been diagnosed with feline leukemia. These cats should be:

• Kept indoors and away from other cats
• Kept on a strict diet without raw meat or eggs
• Have regular checkups with their vet
• Seek veterinary care at first sign of an illness
• Kept up-to-date on vaccines
• Have regular fecal tests and deworming

Remember, cats with FeLV are more prone to developing other illnesses so you must do what you can to protect the state of their health.

Can you vaccinate a cat against feline leukemia?

There is a vaccination, (typically covered with pet insurance) and you can discuss this with your vet. However, it will do nothing for a cat that is already infected.