Rickettsia africae is a re-emerging tick-borne pathogen causing African tick bite fever (ATBF) in humans. Amblyomma variegatum is the principal vector in most sub-Sahara African countries, whereas in South Africa it is A. hebraeum. Reports of high genetic heterogeneity among R. africae isolates in southern Africa have prompted the need for molecular investigations of isolates form South Africa. Therefore, this study aimed to determine the prevalence and genetic diversity of R. africae in A. hebraeum collected from cattle, grazing pasture, as well as from blood of cattle in the Eastern Cape Province of South Africa. Amblyomma hebraeum and blood from cattle were screened by PCR and the gltA, ompA, ompB, sca4, and 17kDa genes were sequenced for R. africae from samples collected from Caquba in Port St. Johns along the coastal region in the Eastern Cape province of South Africa. The overall proportion of adult A. hebraeum that were positive for the gltA and ompA genes was 0.63 (108/180). The overall proportion of nymphs positive for the gltA and ompA genes was 0.62 (23/37) and 0.22 (20/90) from cattle blood. A positive R. africae infection was inferred by analysis of 26 sequences of the ompA, gltA, ompB, 17kDa and sca4 genes. Neighbour-joining and Maximum Likelihood analysis revealed that the study isolates were closely related to R. africae isolates from South Africa deposited in GenBank, forming a clade that was separate from north, east and west African strains. This study provides new information on the epidemiology and phylogeny of R. africae isolated from A. hebraeum ticks in the Eastern Cape province of South Africa. The heterogeneity observed between R. africae isolates from South Africa deposited in GenBank and R. africae isolates from Africa retrieved from Genbank highlight the importance of differentiation and tracking of the genetic movement among R. africae isolates in southern Africa for the better characterisation of ATBF cases, especially in rural communities and travellers visiting the region.

非洲立克次体是一种重新出现的tick传播病原体，可引起人类非洲tick叮咬热（ATBF）。花蜱叶木是在大多数撒哈拉以南非洲国家的主要载体，而在南非是A. hebraeum。中高遗传异质性报告R. Africae酒店在非洲南部的分离，促使需要分离的分子生物学研究形成南非。因此，本研究旨在确定南非东开普省从牛，放牧牧场以及牛血中收集的非洲黑斑病菌在非洲黑斑病菌中的流行和遗传多样性。胸膜盲肠并通过PCR筛选牛血，并对南非东开普省沿海地区圣约翰港Caquba采集的样品中的R. africae的gltA，ompA，ompB，sca4和17kDa基因进行测序。gltA和ompA基因呈阳性的成人A. hebraeum的总比例为0.63（108/180）。从牛血中，gltA和ompA基因阳性的若虫的总比例为0.62（23/37）和0.22（20/90）。阳性非洲假单胞菌通过分析ompA，gltA，ompB，17kDa和sca4基因的26个序列来推断感染。邻域连接和最大似然分析表明，该研究菌株与GenBank上存放的南非非洲假单胞菌菌株密切相关，形成了与北非，东非和西非菌株分离的进化枝。这项研究提供了关于从南非东开普省的希伯来tick中分离出的非洲黑斑病菌的流行病学和系统发育的新信息。在GenBank和南非存放的南非非洲分支杆菌分离株之间观察到异质性。R. Africae酒店隔离来自非洲检索从基因库分化凸显的重要性和之间的遗传运动的跟踪R. Africae酒店在南部非洲的ATBF情况下更好地表征分离，尤其是在农村社区和旅行者访问该地区。