A 49-year-old healthy female presented to the emergency department with a headache, fever to 103°F, mild myalgia, heart rate of 119 bpm, and blood pressure of 80/40 mm Hg. Past medical history was unremarkable, no drug allergies or current medications, except for a recent vacation in eastern Washington state. The complete blood count showed a white blood cell count of 12.5 × 10E9/L (mild leukocytosis with left shift), thrombocytopenia (32 000/µL), normal electrolytes, and an elevated C-reactive protein (19.8 mg/dL). Blood cultures were sterile. The peripheral blood smear revealed spirochetes morphologically resembling Borrelia species ( Borrelia sp) and were considered confirmatory for relapsing fever (RF). Serological testing for Borrelia sp on acute and convalescent specimens exhibited negative and positive immunoglobulin G antibodies to B hermsii, respectively. She was treated with ciprofloxacin and made a full recovery.Although the therapy for tick- or louse-borne borreliosis is well established and the response to antibiotics is predictably good, RF is a communicable disease and must be reported by laboratories to the local health department.