Anaplasma (아나플라즈마) Anaplasma phagocytophilum (formerly Ehrlichia phagocytophilum) is a Gram-negative bacterium that is unusual in its tropism to neutrophils. It causes anaplasmosis in sheep and cattle, also known as tick-borne fever and pasture fever, and also causes the zoonotic disease human granulocytic anaplasmosis. A. phagocytophilum is a Gram-negative, obligate bacterium of neutrophils. It..