Abstract
Relapsing fever is endemic in some parts of the world such as Africa, South America, and Far East.(1-3) Epidemics have occurred among refugees and war victims in some parts of Africa.(4,5) There is very little information about this infection in Saudi Arabia. The prevalence or incidence in Saudi Arabia is unknown. Its apparent rarity may be due to under diagnosis and under reporting. A high index of suspicion in appropriate clinical situations will lead to its early recognition and treatment. Relapsing fever is an acute febrile illness caused by blood spirochetes belonging to genus borrelia. This spirochete can be acquired through the bite of an infected soft tick (Ornithodoros species) or contact with the hemolymph of an infected human body louse (Pediculus humanus) and thus constituting two types of relapsing fever (RF) depending upon the responsible vector i.e. Tick - borne relapsing fever (TBRF) and Louse - borne relapsing fever (LBRF). It is characterized by recurrent cycles of pyrexia which are separated by intervals of apparent recovery. During pyrexia, organisms can be found in blood and that is the only way of reliable diagnosis in many situations.(6,7) While during afebrile period, organisms hide themselves in spleen, liver and even central nervous system.