An Unusual Presentation of Murine Typhus and Mononucleosis.

A 20-year-old female presented to the emergency department complaining of fever, cough, and dyspnea after a recent camping trip. The patient remained ill appearing, persistently tachycardic and dyspneic despite nebulizer treatments, and fluids in the emergency department. She was admitted for observation and gradually improved over the next 4 d. Inpatient laboratory studies indicated acute Epstein-Barr virus infection and she was discharged with a presumptive diagnosis of infectious mononucleosis. However, further testing showed a simultaneous rickettsial infection producing murine typhus. The patient ultimately recovered uneventfully once proper treatment was initiated. This patient's presentation represents a unique description of simultaneous infectious mononucleosis and murine typhus which underscores the importance of maintaining a broad differential diagnosis in the approach to febrile illnesses.