Cats bring companionship, comfort, and joy into our lives, but just like people, they can be affected by viruses. One such concern is the feline leukemia virus, or FeLV. While its name may sound scary, understanding what FeLV is, how it spreads, and what treatment options exist can help you make the best choices as a pet parent.
What Is Feline Leukemia?
FeLV is a retrovirus, a type of virus that can incorporate itself into a cat’s genome. In cats, FeLV can lead to a wide range of problems, including immune suppression, cancer, and blood disorders.
In the United States and Canada, about 2–3% of all cats test positive for FeLV. However, among sick or high-risk cats, such as kittens or cats in shelters, this number can climb to up to 30%. Vaccination and improved testing over the past few decades have significantly reduced FeLV prevalence and impact.
How Do Cats Catch FeLV?
FeLV is mainly passed from cat to cat through close contact. The virus is shed through bodily fluids like saliva, nasal secretions, urine, feces, and milk.
Common ways the virus spreads include:
- Grooming and close contact: Friendly interactions like shared food bowls and mutual grooming.
- Bites: Deep wounds can transmit the virus.
- Mother to kitten: Infected mothers may pass the virus during pregnancy or through nursing.
Luckily, FeLV doesn’t survive long in the environment, probably just a few hours under typical household conditions, so casual contact with contaminated surfaces is unlikely to spread the virus.
How Does FeLV Affect a Cat?
When a cat tests positive for FeLV, there are a few different outcomes, and understanding them can help you plan the next steps with your veterinarian.
Some cats experience a transient infection, meaning they were exposed to the virus but may successfully clear it from their system before it can incorporate into their genome. These cats often test positive on an initial screening but negative on a follow-up test taken 3–4 months later. If your cat falls into this category, your vet may recommend retesting to confirm whether the virus has truly been eliminated. If so, they may return to a typical lifestyle, and you’ll want to continue with preventive steps moving forward.
Other cats become healthy carriers, also known as regressors. In these cases, the virus becomes dormant within the cat’s body. These cats may not show any signs of illness and can live relatively normal lives.
However, the virus can reactivate later, especially during times of stress or illness. Regular monitoring, a calm indoor lifestyle, and excellent general care are key to helping these cats thrive while minimizing risks.
In persistently infected cats, the virus remains active and continues to affect the immune system.
How is FeLV Diagnosed?
Your veterinarian can screen for FeLV using:
ELISA test (at the clinic): This test detects viral antigens in the blood. If positive, it’s often confirmed with a second test after 3–4 months to distinguish transient from persistent infection.
IFA test (sent to a lab): This test detects the virus in white blood cells, which usually indicates a longstanding, persistent infection.
Polymerase Chain Reaction (PCR): This test detects whether the virus has been incorporated into the cat’s genome.
Early diagnosis matters, whether your cat recovers, becomes a carrier, or progresses, because it guides treatment, lifestyle adjustments, and helps protect other cats in the home.
Signs Your Cat May Have Feline Leukemia
FeLV can have many adverse effects on a cat’s health, most notably causing blood disorders, cancer, and immune deficiency. When a cat is initially infected, they typically won’t show symptoms, but as it progresses, you may notice your cat showing signs such as:
- Progressive weight loss
- Poor fur condition
- Pale gums/mucus membranes
- Loss of appetite
- Persistent fever
- Persistent Diarrhea
- Various eye conditions
- Abortion of kittens/reproductive failure
- Behavior changes
- Seizures
- Neurological disorders
- Infections in the skin, upper respiratory tract, and bladder
If you notice these signs or think your cat may have been exposed, it is critical to have it seen by its veterinarian as soon as possible for a diagnosis and treatment.
Is There a Cure? How is Feline Leukemia Treated?
Currently, no cure for FeLV exists. Once a cat is persistently infected, the virus integrates into its genome and remains for life. However, treatment and management can significantly affect a cat’s well-being and lifespan.
Treatment options for feline leukemia include:
- Supportive & symptomatic care
Treat secondary infections with antibiotics - Provide nutritional support
- Offer blood transfusions or medications for anemia
- Care for any tumors that develop (e.g., chemotherapy, surgery)
Can Feline Leukemia Be Prevented?
Yes, cat owners can prevent FeLV in a number of ways, including:
Vaccination
FeLV vaccines significantly reduce infection risk and are considered core for kittens and high-risk cats (e.g., outdoor cats, indoor cats living with FeLV-positive cats). Types of vaccines include killed-virus, subunit, and canarypox-based recombinant versions (such as PUREVAX FeLV).
Rarely, FeLV vaccines are linked to injection-site sarcomas (a type of cancer). This risk is low, and vaccine protocols are now carefully structured to minimize the chance of adverse reactions.
Testing new cats
Any new cat joining your household should be tested before introduction to avoid unintended spread.
Limiting exposure
Keep FeLV-positive cats isolated: they should only live with other FeLV-positive cats.
Keep indoor cats inside (no outdoor access).
Supervise outdoor cats or create safe spaces where they can’t interact with unknown cats.
Routine screening
Healthy adult cats benefit from periodic FeLV testing, especially if their exposure risk changes.
Feline Luekemia Treatment at The Animal Medical Center of Streetsboro
FeLV might sound intimidating, but it’s a manageable condition with the right tools and awareness. Here’s your action plan:
- Vaccinate your kitten or cat (especially if exposure risk is present).
- Test new pets before bringing them into your home.
- Retest after early exposure to catch transient cases.
- Provide indoor living, good nutrition, and prompt veterinary attention.
- Talk to your vet about immunomodulators if your cat tests positive.
By staying informed and proactive, you can help your cat live a life full of love, comfort, and dignity, even in the face of FeLV.
We’re here for all your feline family members, from wellness checks and vaccinations to testing, tailored treatment plans, and supportive care for FeLV-positive cats. Contact us today to schedule an appointment!
