Symptoms2026-03-09Carelogy編集部
FeLV & FIV in Cats: Testing, Transmission & Management Guide
Complete guide to Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV): testing, transmission routes, and management of positive cats.
The Bottom Line: FeLV/FIV-Positive Cats Can Live Long, Happy Lives
Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV, often called "feline AIDS") are the two major retroviral infections in cats. Despite their scary reputations, many FIV-positive cats remain symptom-free and live a normal lifespan. FeLV tends to carry a more guarded prognosis, yet even FeLV-positive cats can thrive for years with proper care.
Every cat should be tested for FeLV and FIV at least once, and testing is absolutely essential when adopting a rescue or shelter cat.
FeLV vs. FIV: Key Differences
Feline Leukemia Virus (FeLV):
- Primary transmission: saliva (mutual grooming, shared food bowls, bite wounds)
- Causes immune suppression and can trigger cancers such as lymphoma
- Vaccine available (recommended for at-risk cats)
- Prognosis: Relatively serious — about 80% of persistently infected cats develop FeLV-related illness within 3 years
Feline Immunodeficiency Virus (FIV):
- Primary transmission: deep bite wounds — casual contact like grooming rarely transmits it
- Causes gradual immune decline similar to HIV in humans, but progression is very slow
- No widely approved vaccine in most regions
- Prognosis: The asymptomatic carrier phase often lasts several years to over a decade
Testing Methods and When to Test
SNAP test (in-clinic rapid test): A single drop of blood screens for both FeLV antigen and FIV antibodies in about 10 minutes. Cost: $25–$40 (¥3,000–5,000).
When to test:
- When bringing a new cat home (mandatory)
- After contact with outdoor or stray cats
- When unexplained illness persists
- If your cat seems lethargic for an extended period
Important caveat: The FIV test detects antibodies, so cats previously vaccinated against FIV or kittens carrying maternal antibodies can produce false positives. Kittens should be retested after 6 months of age.
Managing Life with a Positive Cat
Indoor-only living: Strictly keeping the cat indoors is essential — both to prevent transmission to other cats and to protect an immunocompromised cat from outside infections.
Regular checkups: Bloodwork twice a year to monitor immune function and organ health.
Stress management: Reducing stress is vital for maintaining immune function. Learn to spot signs of stress in cats and create a calm, enriched environment.
Nutrition: Feed a high-quality, nutritionally complete diet. Avoid raw meat, which carries infection risk for immunocompromised cats.
Multi-cat households: FIV is transmitted only through bite wounds, so bonded cats that do not fight can often coexist safely. FeLV spreads through saliva, so separation is recommended.
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FeLVFIV猫白血病猫エイズウイルス猫の病気
