RESUMEN
A 53-year-old man visited Mt. Arashima-dake in Fukui Prefecture, and was infested by a tick-like organism. He visited a local clinic on July 12, 2004, complaining of high fever, general fatigue and rash. After several days without definite diagnosis, he was admitted to the Fukui Prefectural Hospital, where he was treated with minocycline hydrochloride for 10 days until recovery. His clinical symptoms on admission were high fever (39.6 degrees C), erythematous eruption, eschar on the right upper arm, and regional lymphoadenopathy. The epidemiological status and some clinical findings strongly suggested spotted fever (SF), and SF was confirmed based on the finding that his sera were reactive only to antigens of the SF group rickettsiae in the indirect immunoperoxidase analysis. This case is the first official report of SF rickettsiosis in Fukui Prefecture, the northern part of central Japan.