Feline immunodeficiency virus (FIV) is a viral infection that affects domestic cats and some wild feline species. It weakens the cat's immune system, making them more susceptible to infections and diseases. FIV is primarily transmitted through bite wounds, so outdoor cats that fight are at higher risk. Cats infected with FIV may not show symptoms for years, but they can still spread the virus to other cats. Regular veterinary check-ups and testing can help manage the health of FIV-positive cats. There is no cure for FIV, but supportive care can improve the quality of life for affected felines.