Abstract：
African tick bite fever (ATBF) is one of the most important rickettsial infections in international travellers to sub-Saharan Africa. The heterogeneity of Rickettsia africae infection rates among tick vector species has been studied. However, this information has not been systematised to allow for comparative estimates. Quantifying the trends and heterogeneity in R. africae infection rates among the different tick vector species is paramount in understanding the role in transmission to humans. A systematic search was conducted in PubMed, Web of Knowledge, Google Scholar, and SCOPUS from 2005 to 2020. The selection criteria included all studies in sub-Saharan Africa reporting R. africae infection rates in tick adults, nymphs, and larvae. A quality effects model was used in the meta-analysis due to the observed heterogeneity with an assessment of publication bias using funnel plots. The prevalence estimates were conducted by geographic region and tick genus from 32 studies reporting R. africae infection rates in ticks from sub-Saharan Africa. A total of 12,301 ticks comprising of adults (96.19%, n=11, 832), nymphs (3.6%, n=443) and larvae (0.2%, n=26) and 1214 pooled samples were evaluated for R. africae infection. The overall prevalence of R. africae was higher in Amblyomma spp. (48%, 95% CI: 26-70%) compared to Rhipicephalus spp. (1%, 95% CI: 0-5%), Hyalomma spp. (1%, 95% CI: 0-3%) and other tick genera (1%, 95% CI: 0-4%) throughout all regions. The highest prevalence in Amblyomma spp. was recorded in western Africa (53%, 95% CI: 14-90%) and in Rhipicephalus spp. in southern Africa (2%, 95% CI: 0-5%). Cattle were the most frequently sampled hosts across all tick vectors (62.98%, n=5492), followed by goats (19.07%, n= 1663) and sheep (9.1%, n= 793). To our knowledge, this is the first systematic and quantitative analysis of R. africae infection in tick vectors collected from mammalian hosts in sub-Saharan Africa. The results highlight a marked heterogeneity between species in different regions of sub-Saharan Africa and provide initial estimates of infection rates.
摘要：
非洲蜱叮咬热（ATBF）是前往撒哈拉以南非洲的国际旅行者中最重要的立克次体感染之一。已经研究了蜱媒介物种之间非洲立克次体感染率的异质性。然而,这些信息还没有系统化，以便进行比较估计。量化不同蜱媒介物种之间非洲R.Africae感染率的趋势和异质性对于理解传播给人类的作用至关重要。在PubMed进行了系统的搜索，WebofKnowledge,谷歌学者，和SCOPUS从2005年到2020年。选择标准包括撒哈拉以南非洲地区的所有研究，这些研究报告了蜱虫成虫中非洲毛虫的感染率，若虫,还有幼虫.由于观察到的异质性，在荟萃分析中使用了质量效应模型，并使用漏斗图评估了发表偏倚。患病率估计是按地理区域和tick属进行的，来自32项研究报告了撒哈拉以南非洲地区tick的非洲R.Africae感染率。共有12,301只蜱，包括成年人(96.19%，n=11,832),若虫（3.6%，n=443)和幼虫(0.2%，n=26）和1214个合并样品的非洲R.Africae感染进行了评估。非洲R.Africae的总体患病率较高。（48%，95％CI：26-70％）与Rhipicephalusspp相比。(1%,95%CI：0-5%），风孔菌属。(1%,95%CI：0-3%)和其他蜱属(1%，95%CI：0-4%）遍及所有地区。弱视中患病率最高。记录在西非(53%，95％CI：14-90％）和Rhipicephalusspp。在南部非洲（2%，95%CI：0-5%）。牛是所有蜱矢量中采样频率最高的宿主(62.98%，n=5492),其次是山羊(19.07%，n=1663)和绵羊(9.1%，n=793）。据我们所知,这是对从撒哈拉以南非洲的哺乳动物宿主中收集的蜱载体中非洲R.Africae感染的首次系统和定量分析。结果强调了撒哈拉以南非洲不同地区物种之间的明显异质性，并提供了感染率的初步估计。
