Human ehrlichiosis and anaplasmosis describe a group of acute febrile tick-borne diseases characterized by an overlapping clinical picture that includes fever, headache, myalgias, arthralgias, skin eruptions, gastrointestinal symptoms and neurological manifestations. Diseases in this group include human monocytotropic ehrlichiosis (HME), human granulocytotropic anaplasmosis (HGA), and human ehrlichiosis ewingii (HEE) (see these terms).