In order to collect recent epidemiological data on Borrelia infection in hospital settings, we conducted a retrospective study in the infectious Diseases Ward in Dakar (Senegal). Over a period of 10 years (January 1987-December 1996), 31 cases were included: 18 from outpatient clinics and 13 inpatients. The cases were unequally distributed for years and occurred with a peak in August (8/31). All patients lived in Dakar in populous areas. Females were more represented (sex ratio= 0.8) and 67.7% of the whole cases ranged 15-34 years. Clinical features of Borrelia infection were dominated by malaria-like symptoms among outpatients, whilst neurological manifestations were prominent among inpatients. Treatment of the latter used three antibiotics: tetracycline, chloramphenicol and erythromycine. No case-related fatality occurred. (C) 1999 Elsevier; Paris.