A Japanese man with malaria tests negative for fever after spending 6 months in rural Kenya

A previously healthy Japanese man in his fifties was admitted to our hospital because of a recurrent fever after returning from Kenya and Madagascar. He was ambulant with a body temperature of 36.6 °C. His physical examination revealed normal except for tender hepatomegaly. The blood test results showed no apparent abnormality except thrombocytopenia and mild liver dysfunction. The rapid diagnostic test and Giemsa-stained blood film were repeatedly negative for malaria. Computed tomography scans of the chest, abdomen, and pelvis revealed no significantly abnormal findings.