A 17-year-old refugee from Eritrea presented with sudden fever (to 41°C), myalgias, and headache. Three days before admission, he had arrived in Switzerland after a long journey through the Sudan and Libya and across the Mediterranean and Italy. Other than mild anemia, he had unremarkable blood values (hemoglobin, 122 g/L; white blood cells, 5.6 × 109/L; platelets, 187 × 109/L) and an increased C-reactive protein of 55 mg/L. No localizing infection was found by clinical examination, chest radiograph, or urine analysis. During a search for malaria, spirochetes were spotted in the blood film (Giemsa stained, original magnification ×100). Given the travel history and clinical symptoms, louse-borne relapsing fever (LBRF) was diagnosed, caused by Borrelia recurrentis. A treatment with doxycycline for 7 days was effective.
Unexpected cause of high fever in the blood film