Feline Infectious Anemia (FIA) is caused by a parasitic bacterium that attaches itself to the red blood cells of the host cat. T

    The infected cat's immune system attacks the parasite with antibodies and kills the bacterium. The problem is that so many red blood cells are being destroyed through the act of killing the parasite that the cat becomes anemic.

    There is speculation that FIA can be passed from one cat to another by parasite insects that can carry blood (fleas, ticks, and mosquitoes) though a definitive cause has not yet been proven.