Feline Immunodeficiency Virus (FIV) in Cats 🐱🧬

By Dr Duncan Houston, BVSc

FIV (Feline Immunodeficiency Virus) is often compared to HIV in humans. While incurable, many FIV+ cats live long, happy lives with the right care. In this 2025 guide, Dr Duncan Houston explains how FIV works, how it’s diagnosed, and how to support your positive feline friend through all life stages. 🧪

🔍 What Is FIV?

FIV is a retrovirus that gradually weakens the cat’s immune system. It leads to feline AIDS but usually only after years of asymptomatic infection. Good husbandry and regular vet care can keep cats healthy for years. 🐾

🧪 How Is FIV Diagnosed?

• 💉 Initial testing via ELISA or SNAP antibody tests (often in-house)
• 🔬 Confirmatory testing via Western Blot or PCR (for viral DNA)
• 🍼 Kittens may test positive from maternal antibodies—retest at 6+ months

Important: The discontinued FIV vaccine causes false positives on antibody tests. PCR can distinguish vaccinated from infected cats. 🧬

💥 How Is FIV Spread?

The virus spreads mainly through bite wounds during fights. It’s not airborne or food-bowl transmissible. Other rare methods:

• 💉 Blood transfusions
• 🤰 Rare maternal transmission during early infection
• 🐾 No evidence for spread through grooming or litter sharing

🏡 Managing an FIV+ Cat

1. 🚪 Keep Indoors Only

• 🚫 Prevent spreading FIV to other cats
• 🛡️ Protect your cat from outside pathogens
• 🐱 Enclosed patios or “catios” may be acceptable

2. 🥩 No Raw Diets

• ⚠️ FIV+ cats have less resistance to foodborne bacteria
• 🧪 Stick with reputable, commercially prepared diets

3. 💉 Vaccination Guidance

Vaccination may reactivate virus in test conditions—but this hasn’t been confirmed in real cats. Follow local vaccine laws and:

• ✅ Continue vaccines if your cat goes outside or needs boarding
• 🛑 Vaccination may be skipped in indoor-only, stable households

4. 🐛 Parasite Prevention

Use flea, tick, and worm prevention consistently to avoid unnecessary immune burden. Consult your vet for a safe product. 💊

🌿 Supplements & Immune Support

Some products claim to help the immune system, but many lack evidence. One with potential:

• 💉 LTCI (by TCyte®): an injectable immunomodulator originally developed for FIV+

🧪 Antioxidants

Oxidative stress contributes to FIV progression. Supplements such as superoxide dismutase may help balance immune cells. 🧬

🩺 Health Monitoring

• 🔍 Twice-yearly checkups are recommended
• 🩸 Annual bloodwork and urinalysis
• ⚠️ Report even minor changes in behavior or weight

Be proactive, not reactive. A small symptom in a normal cat could mean much more in an FIV+ cat. 🐾

💊 Antiviral Medications

While not routinely used, AZT (zidovudine) can benefit cats with:

• 🧠 Neurological symptoms
• 🦷 Stomatitis (chronic mouth inflammation)

AZT requires close monitoring for side effects. Other human HIV drugs are not recommended due to feline toxicity. 🧫

🙅‍♀️ FIV & Human Health

FIV is not transmissible to humans or other non-feline species. But be cautious in homes where both pet and owner are immunocompromised—cross-infection risk of unrelated pathogens is higher. 🧍‍♂️🧪

📱 Ask A Vet App Support

Managing an FIV+ cat? The Ask A Vet app is your 24/7 support system:

• 🩺 Schedule follow-ups and upload lab results
• 💬 Chat with licensed vets about treatment options
• 🧾 Get food, supplement, and medication guidance
• 🧪 Discuss immune support strategies

🏁 Final Takeaway

FIV is not a death sentence. With indoor living, preventive care, and routine monitoring, most cats can live long and fulfilling lives. Keep stress low, watch for subtle changes, and always advocate for your cat’s evolving health needs. For help every step of the way, download the Ask A Vet app. 🐱🛡️❤️