Post Exposure Treatment With Doxycycline for the Prevention of Relapsing Fever

Abstract Background Tick-Borne Relapsing Fever (TBRF) is an acute febrile illness. In Israel, TBRF is caused by Borrelia persica and is transmitted by Ornithodoros tholozani ticks. We examined the safety and efficacy of a post exposure treatment policy to prevent TBRF.

Methods In a double blind, placebo controlled trial 93 healthy volunteers with suspected tick exposure (51 with bite signs and 42 contacts) were randomly assigned to receive either Doxycycline (200 mg for the first day and 100mg/d for 4 days) or placebo, approximately 2 days after contact. Blood smears were examined for Borrelia at inclusion and during fever rise. Serology for Lyme disease cross- reactivity and PCR for Borrelia GlpQ gene were also performed. Cases of TBRF were defined as subjects having fever and a positive blood smear.