What is FIV (Feline Immunodeficiency Virus)?
A virus that weakens a cat's immune system, similar to HIV in humans, transmitted mainly through bite wounds during fights between cats.
FIV (Feline Immunodeficiency Virus) is a retrovirus that attacks a cat's immune system cells, leaving the cat increasingly vulnerable to opportunistic infections over time. The main route of transmission is deep bite wounds during fights, which makes unneutered male cats with outdoor access the group at highest risk. FIV cannot be transmitted to humans or dogs — it is a cat-specific disease, distinct from HIV, though it belongs to the same family of viruses.
A cat can be infected for years without showing any visible symptoms. When signs do appear, they usually reflect the decline in immunity: mouth infections (chronic gingivitis and stomatitis), recurrent respiratory infections, skin wounds that heal slowly, intermittent fever, weight loss, and increased susceptibility to other infectious diseases.
There is no cure for FIV, but many infected cats live for years with a good quality of life when kept in a controlled environment (ideally indoors only, to avoid fights and transmission to other cats), with regular veterinary follow-up and prompt treatment of any secondary infection. Diagnosis is made through a blood test. See a veterinarian to test a cat with a history of fighting, outdoor access, or recurrent infections and unexplained weight loss.
Important notice
This calculator is for educational purposes and does not replace a veterinary evaluation. When in doubt, consult a veterinarian.Related terms
FeLV (Feline Leukemia Virus)
A virus that affects a cat's bone marrow and immune system, potentially causing anemia, immunosuppression, and certain cancers; transmitted through close contact between cats.
Complete Blood Count (CBC)
A blood test that evaluates red blood cells, white blood cells, and platelets, used to investigate anemia, infection, inflammation, and clotting problems.