IDENTIFICATION OF RICKETTSIAE FROM TICKS COLLECTED IN THE CENTRAL-AFRICAN-REPUBLIC USING THE POLYMERASE CHAIN-REACTION

Spotted fever rickettsiosis have been identified on the African contin ent since their historical description in 1909. However, only Ricketts ia conorii and R. africae have been described in Africa, and the curre nt techniques for the detection of rickettsiae in ticks are difficult to apply in large field studies. We report here a preliminary study us ing genomic amplification by the polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) analysis directly on 310 crushed ticks (Rhipicephalus, Amblyomma, and Haemaphysalis spe cies) collected in 1985 in the Central African Republic. Among 310 spe cimen tested, 21.6% were positive. The rate of infection ranged from 0 % to 64.3%, depending on the tick species. Based on PCR-RFLP, five dif ferent rickettsiae profiles were found: R. conorii and R. africae, pre viously known in Africa, R. rhipicephali, which has never been describ ed in Africa, and two isolates identical to R. massiliae and Mtu5, pre viously obtained from Rk. turanicus in southern France. This work show s that PCR-RFLP is a powerful tool to study tick collections, and that it is applicable to samples from developing countries. Further work i s needed to confirm the identification of the rickettsiae found in thi s work, using traditional identification procedures.