FeLV and FIV
What is it?
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses that weaken the immune system. FeLV spreads through close contact such as mutual grooming and shared bowls, and can cause anemia and cancer. FIV spreads mainly through bite wounds and progresses slowly.
What signs should I watch for?
Signs to watch for include recurrent or slow-to-heal infections; weight loss and poor appetite; gum and mouth inflammation; pale gums (anemia); and enlarged lymph nodes, fever.
How is it diagnosed and treated?
Simple in-clinic blood tests screen for both; positive results are often confirmed with additional testing. There is no cure; care focuses on keeping the cat healthy, treating secondary illnesses promptly, and regular checkups.
Can it be prevented, and what's the outlook?
- Test all new cats, keep cats indoors, and vaccinate against FeLV when recommended.
- Many FIV-positive cats live normal lifespans.
Reviewed by the Adler Veterinary Hospital veterinary team, October 2026.
Cats with outdoor access or untested cagemates
Who's at risk:
Recurrent infections, weight loss, mouth inflammation, pale gums
Main signs:
Ongoing management with your vet
Urgency:
When to call a vet right away
- Pale gums (anemia can be life-threatening)
- Fever, or infections that keep coming back
- Not eating, or weight loss
- Severe diarrhea
- New eye problems or neurologic signs
Not sure whether it can wait? Call us anyway. Our team can help you decide.
Source:
Related conditions
Bite Wounds & Abscesses
Heart Disease (HCM)
Respiratory Infections