Ehrlichiosis and anaplasmosis

Ehrlichiosis and anaplasmosis are tick-borne zoonoses caused by rickettsiae. Characteristic infectious syndromes have been described in multiple mammals, including humans. Patients typically present with acute onset of nonspecific fever, headache, and myalgias 1 to 2 weeks after being exposed to or bitten by a tick. Most patients experience a self-limited illness and recover uneventfully. However, fatal outcomes have been described, and specific antibiotic therapy (typically doxycycline) should be administered to all patients who are clinically symptomatic. The diagnosis requires a high index of suspicion and is frequently made retrospectively.