[Recurrent tick-borne fever: a possible diagnosis in patients returning from Senegal].

In Senegal, tick-borne relapsing fever caused by the spirochetes Borrelia crucidurae is the most common cause of fever after malaria in rural areas. However, this is only rarely diagnosed in France, probably because: i) the diagnosis relies on investigations that are not routinely done; ii) even undiagnosed, borreliosis may be cured with empirical antibiotic treatment. We report four observations of tick-borne relapsing fever in patients returning from Senegal: In two patients, the diagnosis relied on the observation of spirochetes in blood smears; in the other two, the diagnosis relied on typical clinico-biological signs, borreliosis serology and exposure. These four cases diagnosed over a four year period in one institution suggest that relapsing fever is not rare in patients returning from West Africa. Patients who return form Senegal with unexplained fever should be investigated with careful examination of blood smears and PCR on blood samples.