Feline Leukemia

Feline leukemia is a serious, widespread disease that compromises a cat’s immune system and can lead to life-threatening illnesses. Central to this issue is the feline leukemia virus (FeLV), a retrovirus transmitted primarily through saliva, blood, or nasal secretions. Once a cat contracts FeLV, it can develop persistent infections, anemia, and even cancer. Early detection is critical, as many affected cats show few signs until the condition progresses. Research has revealed that young kittens and cats with weakened immunity face the highest risk, underscoring the importance of regular testing and vaccination. Although significant strides have been made in understanding FeLV, it remains one of the most common infectious causes of cat-related fatalities. By learning more about the feline leukemia virus and prioritizing preventative care, cat owners and veterinarians can collaborate to minimize transmission and improve outcomes, giving infected felines the best possible chance at a healthy life and extended longevity.

Today is Feline Leukemia Day. This is one of the more serious kitty holidays on the calendar, but it is an important topic. Feline leukemia is much more common than any of us would like: it affects between two and three percent of our furry pals. A Brampton, ON vet goes over some basic facts about the disease below.

It Affects Fluffy’s Immunity

The feline leukemia virus (FeLV) virus compromises Fluffy’s immunity, leaving her very vulnerable to secondary infections, such as skin or respiratory problems. She’ll also be at higher risk of developing certain cancers. The disease can also significantly shorten her lifespan.

Risk Factors

There are several risk factors to keep in mind. Kittens born to FeLV-positive mommas are of course at greatest risk. Males are also more likely to be infected than females. Living with an infected cat also increases Fluffy’s odds. Outdoor cats are also at elevated risk, as are those in multi-cat homes.

Transmission

Don’t worry: you can’t catch FeLV. However, it is quite contagious between kitties. Bites and scratches are common forms of transmission. However, Fluffy can also get it by sharing bowls or litterboxes with an infected cat.

Vaccines

The best way to protect your kitty from feline leukemia virus? Get her vaccinated! The vaccine is usually administered to kittens when they’re around two months old. Fluffy will also need boosters. Ask your vet for recommendations.

Immunity

Some cats are able to fight the virus off, which will effectively render them immune to it. However, even if Fluffy is asymptomatic and purrfectly healthy, she could still transmit it to other cats.

Warning Signs

FeLV is typically asymptomatic at first. It doesn’t always progress at the same rate; however, symptoms can appear in just a few weeks. Some things to look for include lethargy, weight loss, respiratory issues, and fever. However, because it’s an immunity issue, this disease can present in many ways, such as through skin infections. It’s important to be aware of various feline health issues, including common problems like hairballs. Learn more about Hairball Awareness Day to stay informed about your cat’s health. Ask your vet for more information on feline leukemia virus and other feline health concerns.

Care

A FeLV-positive diagnosis isn’t good, but it isn’t the end of the world. Fluffy will need some extra TLC: you’ll need to be diligent about keeping her things clean and making sure she stays inside. FeLV-positive cats also need more frequent veterinary appointments, which may include veterinary diagnostics to monitor their health status. However, with good TLC, your furry friend can still lead a wonderful life … or nine!

Feline Leukemia Virus in 2025: Pathogenesis and Disease Progression

What specific cells does FeLV attack in the cat’s body?

FeLV primarily targets the immune system of cats by infecting and killing cells in the hematopoietic system, which includes various types of white blood cells. This detrimental effect on white blood cells compromises a cat’s immune defenses, making them highly susceptible to secondary infections, various forms of cancer, and other health complications that can decrease life expectancy. Understanding the impact of FeLV on these crucial immune cells is vital for managing the health and well-being of infected felines.

How exactly does the virus replicate and spread within the cat’s system?

Feline leukemia virus (FeLV) primarily replicates within a cat’s white blood cells, severely impairing the immune system. The virus utilizes the host’s cellular machinery to produce new viral particles, which are then released and can infect other cells. This spread typically occurs through close contact, such as biting or scratching, and less commonly through shared food and water bowls or litterboxes. Once inside the body, the virus continues to replicate, spreading to other lymphoid tissues and contributing to various health issues, including secondary infections and cancer.

What percentage of cats can naturally eliminate the virus?

A subset of cats has the ability to naturally eliminate the feline leukemia virus (FeLV) from their bodies. Research indicates that about 70% of cats exposed to FeLV can mount an effective immune response that prevents them from becoming persistently infected. These cats can suppress the virus, preventing its spread within their body and significantly reducing the risk of transmitting FeLV to other cats. This immune response is critical for managing the disease in feline populations and highlights the importance of monitoring and supporting feline immune health.

What is the average life expectancy for FeLV-positive cats?

The average life expectancy for cats diagnosed with FeLV can vary significantly based on numerous factors, including the stage at which the disease is detected and how it progresses. Typically, once a cat shows clinical signs of FeLV, the prognosis becomes more guarded. Many FeLV-positive cats may live only a few years after diagnosis, with a substantial number suffering from related health issues like secondary infections or cancers that can further shorten their lifespan. Early detection and comprehensive care are crucial for extending their quality of life.

Can FeLV become dormant and reactivate later?

Yes, FeLV can become dormant within a cat’s body and reactivate later. Some cats initially control the infection well, appearing healthy and asymptomatic for a period, but the virus can persist in a latent state within the bone marrow. Under certain circumstances, such as immune suppression or other health stresses, FeLV can reactivate, leading to clinical signs of the disease. This reactivation highlights the importance of regular veterinary check-ups for cats known to have been exposed to FeLV.

Do you have questions about FeLV? Contact us, your Brampton, ON pet hospital, today!