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蜱传病原体，可引起人类非洲蜱叮咬热 (ATBF)。 Amblyomma variegatum是大多数撒哈拉以南非洲国家的主要媒介，而在南非则是A. hebraeum 。关于南部非洲非洲红线虫分离株之间高度遗传异质性的报道提示需要对来自南非的分离株进行分子研究。因此，本研究旨在确定从南非东开普省的牛、放牧牧场以及牛血液中收集的A. hebraeum中R. africae的流行率和遗传多样性。通过PCR对Amblyomma hebraeum和牛的血液进行了筛选，并从南开普省东开普省沿海地区圣约翰斯港卡库巴收集的样本中对非洲R. amblyomma hebraeum和牛的血液进行了gltA 、 ompA 、 ompB 、 sca4和17kDa基因测序。非洲。 gltA和ompA基因呈阳性的成年A. hebraeum的总体比例为 0.63 (108/180)。来自牛血的gltA和ompA基因阳性若虫的总体比例为 0.62 (23/37) 和 0.22 (20/90)。通过分析ompA 、 gltA 、 ompB 、 17kDa和sca4基因的 26 个序列，推断非洲红线虫阳性感染。邻接和最大似然分析表明，研究分离株与R密切相关。 来自南非的非洲菌株存放在基因库中，形成了一个与北非、东非和西非菌株不同的分支。这项研究提供了关于从南非东开普省的A. hebraeum蜱中分离出的R. africae的流行病学和系统发育的新信息。在 GenBank 中保藏的南非R. africae分离株和从 Genbank 检索到的非洲R. africae 分离株之间观察到的异质性突出了区分和跟踪南部非洲 R. africae分离株之间遗传运动的重要性，以更好地表征 ATBF 病例特别是在农村社区和访问该地区的旅行者中。