Cats can be infected by a tiny red blood cell parasite that was formerly called Hemobartonella felis. This disease, which results from a bacterial infection, is referred to as feline infectious anemia. The infectious agents responsible for the disease have been renamed C. Mycoplasma haemominutum (CMhm) for the small sized strain and Mycoplasma haemofelis for the large sized strains. It is important to make this distinction because these two subtypes of the blood parasite produce quite different clinical signs.