Mycoplasma haemofelis (formerly Haemobartonella felis) is a gram negative epierythrocytic parasitic bacterium. It often appears in bloodsmears as small (0.6μM) coccoid bodies, sometimes forming short chains of 3 to 6 organisms. It is usually the causative agent of Feline Infectious Anemia (FIA) in the United States. Recent evidence suggests that M. haemofelis may be transmissible to humans.