What It Is:
Feline Leukemia Virus (FeLV) is a contagious retrovirus that affects cats’ immune systems and can lead to anemia, cancer, and increased vulnerability to other infections. It’s one of the most serious infectious diseases in cats, but also one of the most misunderstood.
FeLV is not a form of cancer itself. The name comes from its association with leukemia and lymphoma, which it can cause. It’s not contagious to humans or other animals, only to cats.
🐾 Common Symptoms
FeLV affects many body systems, so signs can vary or appear gradually over time.
- Weight loss
- Loss of appetite
- Pale gums
- Fever
- Enlarged lymph nodes
- Diarrhea
- Chronic infections (e.g. respiratory, oral, or skin)
- Poor coat condition
- Lethargy
- Seizures or neurologic signs (in advanced cases)
- Gingivitis or stomatitis
- Reproductive failure in breeding cats
Some cats may carry the virus for months or years before showing symptoms.
🦠 How It Spreads
FeLV is spread through close contact with infected cats, mainly via:
- Saliva (mutual grooming, shared food bowls)
- Nose-to-nose contact
- Bite wounds
- Urine and feces (less commonly)
- From mother to kittens (in utero or while nursing)
FeLV doesn’t survive long outside the body. Casual exposure to surfaces is not a common risk.
Outdoor cats, kittens, and cats in shelters or multi-cat households are at highest risk.
🔍 Diagnosis
Testing is essential since cats can appear healthy while carrying the virus.
Two primary tests:
- ELISA test (screens for virus in the blood, often used in clinics)
- IFA test (confirms persistent infection, sent to a lab)
Kittens should be tested after 8 weeks of age and again a few weeks later to confirm status.
A positive test doesn’t always mean immediate illness. Some cats live symptom-free for years.
💊 Treatment
There is no cure for FeLV, but supportive care can help affected cats live longer, more comfortable lives.
Treatment may include:
- Regular veterinary exams
- Prompt treatment of infections
- High-quality nutrition
- Immune-boosting supplements (as recommended)
- Management of symptoms like anemia, diarrhea, or inflammation
- Avoidance of raw food diets (to reduce infection risk)
Antiviral medications and interferons have been used in some cases, but results vary and are not standard.
🩺 Prognosis
Prognosis depends on the individual cat.
- Some cats eliminate the virus on their own and test negative later
- Others remain carriers without symptoms for months or years
- Some develop progressive illness and live 2 to 3 years post-diagnosis
With supportive care, many FeLV-positive cats enjoy good quality of life, especially in low-stress, indoor-only environments.
💡 Cat Owner Note
A FeLV-positive diagnosis is not a death sentence. It means your cat needs a little more care, a little more caution, and a lot of love. Many FeLV cats live happily for years and often, they’re the ones who know how to soak up every ounce of comfort you offer.
❓ Frequently Asked Questions About FeLV
Can cats recover from FeLV?
Some cats clear the infection, but most become carriers. Even if they don’t show symptoms right away, regular monitoring is important.
Is there a vaccine for FeLV?
Yes. The FeLV vaccine is available and often recommended for outdoor cats, kittens, or cats in multi-cat homes. It’s not 100% effective, but it significantly reduces the risk.
How is FeLV different from FIV?
Both are retroviruses, but FeLV is more likely to cause cancer or anemia, and spreads more easily. FIV spreads mainly through deep bites and tends to progress more slowly.
Can FeLV-positive cats live with FeLV-negative cats?
Only if the negative cats are vaccinated and there’s no sharing of saliva or close grooming. Otherwise, it’s best to keep FeLV-positive cats separated.
Can humans or dogs catch FeLV?
No. FeLV affects only cats.
Should I euthanize a FeLV-positive cat?
Not if they’re otherwise healthy. Many FeLV-positive cats live happy lives and should not be euthanized based on test results alone.