Feline Leukemia Awareness

By Dr. Liz Mulhall, DVM, Director of Shelter Medicine

Feline Leukemia awareness Day is July 15.

A few months ago, our Medical team updated their policies surrounding testing cats for Feline AIDS (FIV) and Leukemia (FeLV) in order to keep up with the most recent data known about these feline retroviruses. We have discontinued our testing practices and updated medical protocols for those cats with FIV or FeLV. With these new procedures, the Admissions Department has been able to relax restrictions for cats who have tested positive for FeLV, now being able to accept a small number of cats with this diagnosis as long as they are stable and relatively healthy. If you would like to surrender a cat who has been diagnosed with FeLV and is not currently showing any major signs of illness, please reach out to our Admissions department or by phone at 412-847-7078.

Please know that we are only able to accept a small number of FeLV cats at this time, so there may be a significant wait before we are able to admit.

To learn more about Feline Leukemia keep reading!

What is FeLV?

FeLV stands for Feline Leukemia. This is one of the most common infectious diseases in cats, affecting about 2-5% of cats in the United States and Canada. FeLV is considered a retrovirus, like FIV, which means once infected the virus remains in the cat’s system and may never fully clear. The virus is most consistently shed through the cat’s saliva but can also be passed through feces, urine, and in the milk of nursing mothers. Cats living in prolonged close contact with those positive for FeLV are at a higher risk of contracting the virus through mutual grooming, shared litterboxes, bite wounds, or at feeding stations. FeLV is commonly referred to as the “friendly cat disease” since mutual grooming is one of the more common routes of transmission. The wonderful thing about FeLV is that once outside of the cat’s body (dried saliva, feces, etc.) the virus does not survive long in a normal environment and will only live maybe a few hours before dying. So, it is highly unlikely a cat will pick up the virus from the environment.

Clinical signs of FeLV

While there can be many ways FeLV can affect a cat when the virus is active, cancer is the most common result. FeLV can also cause various blood disorders and also affects their immune system and in this case they may be unable to fight off other infections that are only minor in healthy cats. FeLV positive cats may never develop any signs of the illness but can also cycle in and out of expressing symptoms of the disease, wreaking havoc on their immune system. Signs of an active FeLV infection may include loss of appetite, progressive weight loss, poor coat condition, enlarged lymph nodes, persistent fever, stomatitis, and other various types of infections.

Cat’s Positive for FeLV

There a three types of infections FeLV positive cats can have: abortive, regressive, or progressive. There are many cases where cats may be in one phase and later improve or decline to another. Because cats may not always test positive, it can be impossible to know with 100% certainty that a cat is negative for leukemia with regular testing.

In abortive infections, cats have been exposed to FeLV, but their immune system was able to successfully eliminate it before it becomes incorporated into their DNA. These cats will test negative for FeLV but will have antibodies in their system creating immunity to the disease. While originally thought to be rare, abortive infections now account for 20-30% of cats exposed develop an abortive infection. They may never test positive using routine testing practices and guardians or vets may never know they have been previously exposed.

In regressive infections, cats who have been exposed are able to eliminate the virus from their bloodstream but have not been able to eliminate it from their DNA. Since the retrovirus is part of their DNA, it will always be in their system and while they are not always infectious to other cats, the virus can be reactivated at any point in their lives. During this time, they may develop clinical signs of FeLV and are also able to transmit the virus to other cats. Regressive infections account for about 30-40% of FeLV positive cats. The majority of the time, these cats will not present with any symptoms of the disease, but it can be reactivated at any time.

Cats with progressive infections come with the worst prognosis. When an FeLV infection is in its progressive phase, cats have a high risk of developing fatal infections and with the virus constantly replicating in their bone marrow, their immune systems are significantly weakened to the point a minor URI infection can become fatal. Cats in the progressive stage are also more likely to infect other cats, with as much as 30-40% of cats exposed to those in the progressive phase contracting the virus.

Treatment and Prevention

There is no cure for FeLV but there have been studies that have shown that various treatments may reduce the volume of FeLV in their blood, but these treatments come with risky side effects and may not always be available for use. With no cure, working with a veterinarian to manage any signs of illness is the best way to care for a cat with FeLV.

To prevent FeLV infection, the best option, and only option, is to prevent exposure to FeLV-infected cats. Cats kept indoors is the best way to prevent accidental exposure to an FeLV-infected cat. If a cat does have access to outdoors, the best way to prevent infection is to keep the cat in an isolated area to prevent interactions with cats of unknown background.

After an FeLV diagnosis

After following any veterinarian recommendations, and treating any signs that may have presented, cats with an FeLV diagnosis can live normal lives for a prolonged period of time. While an FeLV diagnosis is devastating, it is does not always mean they cannot have a normal cat life. It is important to have a good relationship with a veterinarian to closely monitor the health of the kitty but on average they can live about 2.5 years, but cats who develop a regressive infection can have a much longer life than those with active infections.