Molecular diagnosis of African tick bite fever using eschar swabs in a traveller returning from Tanzania.

African tick bite fever is an emerging infectious disease among travellers caused by the pathogen Rickettsia africae. Most travel-associated cases have been reported from countries in southern Africa. So far it has rarely been reported among travellers to eastern Africa and our patient is one of the first described cases imported from Tanzania. A woman presented with fever, chills, headache, myalgia and a rickettsial eschar on her ankle after returning from Tanzania. The diagnosis of African tick bite fever is often based on clinical grounds due to a lack of reliable diagnostic tests at commencement of symptoms. In this patient direct molecular detection of R. africae was performed by PCR from a sample obtained non-invasively with a swab from the rickettsial eschar. A positive PCR result was achieved although the patient had already started antibiotic treatment with doxycycline. In conclusion, this non-invasive method enables early diagnosis of African tick bite fever by direct molecular detection of R. africae and might improve the management of undifferentiated fever in travellers from Africa.