Outbreak of Rickettsia africae infections in participants of an adventure race in South Africa

Abstract

African tick-bite fever, caused by Rickettsia africae and transmitted by Amblyomma ticks, is an emerging rickettsiosis in southern Africa. Because of increased tourism to this area, several cases in tourists have been reported recently. We report 13 cases of R. africae infection diagnosed in France that occurred in competitors returning from an adventure race in South Africa and compare our data with previously reported findings. Most of our patients presented with fever, headache, multiple inoculation eschars, and regional lymphadenopathies, but only 15.4% had a cutaneous rash. Diagnosis was confirmed either by isolation of R. africae from an eschar biopsy specimen or by serological methods, including cross-adsorption between R. africae and Rickettsia conorii. The purpose of this study was to raise physicians' awareness of R. africae infections in an attempt to facilitate the rapid diagnosis and treatment of imported African tick-bite fever in developed countries.