Tick-borne Relapsing Fever Caused by Borrelia hermsii, Montana

Abstract

Five persons contracted tick-borne relapsing fever after staying in a cabin in western Montana. Borrelia hermsii was isolated from the blood of two patients, and Ornithodoros hermsi ticks were collected from the cabin, the first demonstration of this bacterium and tick in Montana. Relapsing fever should be considered when patients who reside or have vacationed in western Montana exhibit a recurring febrile illness.

Keywords

• tick-borne relapsing fever
• Borrelia hermsii
• Ornithodoros hermsi
• Montana
• United States