Feline Leukemia Virus (FeLV): Symptoms, Treatment & Prevention Guide

What is Feline Leukemia Virus?

Feline leukemia virus (FeLV) is a retrovirus that is one of the most common infectious diseases in cats, affecting approximately 2-3% of all cats in the United States. FeLV suppresses the immune system and can cause various cancers, making it a leading cause of death in cats.

How FeLV Is Transmitted

• Saliva: Mutual grooming, sharing food/water bowls
• Nasal secretions: Sneezing, close contact
• Urine and feces: Shared litter boxes
• Blood: Bite wounds, blood transfusions
• Mother to kitten: Transplacental or through milk

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Symptoms

Early Stage (Weeks to Months)

• No symptoms (asymptomatic carriers)
• Mild fever
• Slightly enlarged lymph nodes
• Weight loss (gradual)

Progressive Stage (Months to Years)

• Persistent fever
• Weight loss and poor coat condition
• Loss of appetite
• Enlarged lymph nodes
• Pale gums (anemia)
• Chronic infections (urinary, respiratory, skin)

Advanced Stage

• Lymphoma (cancer of lymph nodes)
• Leukemia (cancer of blood cells)
• Severe anemia
• Immune-mediated diseases
• Kidney disease
• Reproductive problems

Who Is at Risk?

• Outdoor cats (highest risk)
• Unvaccinated cats
• Kittens (more susceptible than adults)
• Multi-cat households
• Cats in shelters and rescues
• Cats with known exposure to FeLV-positive cats

Diagnosis & Costs

Diagnostic Tests

• ELISA SNAP test (screening): $40-80, results in 10 minutes
• IFA test (confirmatory, bone marrow involvement): $100-200
• CBC (anemia, abnormal cells): $80-150
• Chemistry panel: $120-250
• Lymph node aspirate/biopsy (if cancer suspected): $200-500

Total Diagnostic Cost: $200-700

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Treatment

There is no cure for FeLV. Treatment focuses on managing symptoms and complications.

Supportive Care

• Routine veterinary visits (every 6 months): $50-100 each
• CBC monitoring (every 6 months): $80-150
• Antibiotics for secondary infections: $30-100/course
• Blood transfusions (for anemia): $200-500 per transfusion
• Chemotherapy (if cancer develops): $500-5,000+
• Immunomodulators (interferon): $50-200/month

Annual Management Cost: $500-$3,000+

Prevention

Vaccination

• FeLV vaccine: $25-45 per dose
• Initial series: Two doses, 3-4 weeks apart
• Annual booster for at-risk cats
• Test before vaccination (must be FeLV-negative)
• Recommended for: Outdoor cats, multi-cat households, kittens

Management

• Keep cats indoors (eliminates exposure risk)
• Test new cats before introducing to household
• Separate FeLV-positive cats from negative cats
• Avoid sharing food bowls and litter boxes

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Life Expectancy

• FeLV-positive cats: 2-3 years average after diagnosis
• With good care: Some live 5+ years
• Kittens born with FeLV: Often die within 1-2 years
• Vaccinated cats: Nearly 100% protected

Stages of Infection

• Abortive infection: Cat clears the virus (30-40% of exposed cats)
• Regressive infection: Virus goes dormant (30-40%)
• Progressive infection: Persistent viremia, disease develops (30%)

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Related: fiv-feline-immunodeficiency-virus, feline-panleukopenia, feline-herpesvirus