Feline Immunodeficiency Virus (FIV) is a retrovirus that affects an estimated 2–5% of the UK cat population. It attacks the immune system, similar to HIV in humans — but FIV is species-specific and cannot be transmitted to humans, dogs, or other animals. An FIV+ diagnosis is not a death sentence: many cats live long, happy, and largely normal lives with appropriate management.
Transmission
- Deep bite wounds are the primary route — the virus is in saliva and blood. Territorial fights between unneutered males are the highest risk
- Not transmitted through casual contact: sharing food bowls, mutual grooming, sneezing. The virus is fragile and dies quickly outside the body
- Rare transmission from mother to kittens (in utero or via milk)
- Neutering dramatically reduces risk by reducing fighting behaviour
Diagnosis
- Simple blood test at your vet detecting FIV antibodies — results in minutes
- Positive results should be confirmed with a second test (PCR or Western blot) as false positives occur
- Kittens born to FIV+ mothers may carry maternal antibodies — retest at 5–6 months
- It can take up to 12 weeks after infection for a cat to test positive
Prognosis & Living with FIV
- Many FIV+ cats remain asymptomatic for years — some for their entire lives
- With good care, an FIV+ cat can live a similar lifespan to an uninfected cat
- The weakened immune system means secondary infections (dental, respiratory, skin) may be more frequent and slower to resolve
- Regular vet check-ups (6-monthly recommended) with blood tests to monitor health
Management
- Keep indoors or provide a catio — prevents spreading FIV to other cats and protects from infections
- High-quality diet to support immune function
- Prompt veterinary treatment for any illness — don’t wait for symptoms to worsen
- Up-to-date flea and worming treatments; routine vaccinations (discuss with your vet as some vets adjust protocols)
- FIV+ cats can live with FIV-negative cats if they have a stable, non-aggressive relationship — the risk of transmission through social contact is very low
FAQs
Is there a vaccine for FIV in the UK?
No — an FIV vaccine exists in the US but is not licensed in the UK. It is also controversial because vaccinated cats test positive on standard FIV antibody tests, making it impossible to distinguish vaccinated cats from infected ones. The best prevention remains neutering (to reduce fighting) and keeping cats indoors or in secure outdoor enclosures.
Reviewed by Dr. Sarah Jenkins, MRCVS
Dr. Jenkins is a fully practicing veterinary surgeon in the UK with over 15 years of clinical experience in small animal medicine and canine behaviour. She reviews and verifies our health content to ensure medical accuracy.
