Tick sampling information.

Ticks are important vectors of zoonotic diseases and play a major role in the circulation and transmission of many rickettsial species. The aim of this study was to investigate the carriage of Candidatus Rickettsia tarasevichiae (CRT) in a total of 1168 ticks collected in Inner Mongolia to elucidate the potential public health risk of this pathogen, provide a basis for infectious disease prevention, control and prediction and contribute diagnostic ideas for clinical diseases that present with fever in populations exposed to ticks. A total of four tick species, Haemaphysalis concinna (n = 21), Dermacentor nuttalli (n = 122), Hyalomma marginatum (n = 148), and Ixodes persulcatus (n = 877), were collected at nine sampling sites in Inner Mongolia, China, and identified by morphological and molecular biological methods. Reverse transcription PCR targeting the 16S ribosomal RNA (rrs), gltA, groEL, ompB and Sca4 genes was used to detect CRT DNA. Sequencing was used for pathogen species confirmation. The molecular epidemiological analysis showed that three species of ticks were infected with CRT, and the overall positive rate was as high as 42%. The positive rate of I. persulcatus collected in Hinggan League city was up to 96%, and that of I. persulcatus collected in Hulun Buir city was 50%. The pool positive rates of D. nuttalli and H. marginatum collected in Bayan Nur city and H. concinna collected in Hulun Buir city were 0%, 28% and 40%, respectively. This study revealed the high prevalence of CRT infection in ticks from Inner Mongolia and the first confirmation of CRT detected in H. marginatum in China. The wide host range and high infection rate in Inner Mongolia may dramatically increase the exposure of CRT to humans and other vertebrates. The role of H. marginatum in the transmission of rickettsiosis and its potential risk to public health should be further considered.

蜱虫是重要的人畜共患病传播媒介，在多种立克次体物种的循环与传播中发挥关键作用。本研究旨在调查采集自中国内蒙古的1168只蜱虫所携带的塔拉斯维奇候选立克次体（Candidatus Rickettsia tarasevichiae，CRT），以阐明该病原体潜在的公共卫生风险，为传染病的预防、控制与预测提供依据，并为蜱虫暴露人群中表现为发热症状的临床疾病提供诊断思路。
研究人员在中国内蒙古的9个采样点共采集到4种蜱虫，分别为嗜群血蜱（Haemaphysalis concinna，n=21）、草原革蜱（Dermacentor nuttalli，n=122）、边缘璃眼蜱（Hyalomma marginatum，n=148）以及全沟硬蜱（Ixodes persulcatus，n=877），并通过形态学与分子生物学方法完成物种鉴定。
本研究采用针对16S核糖体RNA（rrs）、gltA、groEL、ompB及Sca4基因的逆转录PCR技术检测CRT核酸，并通过测序确认病原体物种。
分子流行病学分析结果显示，共有3种蜱虫感染了CRT，总体阳性率高达42%。其中，兴安盟采集的全沟硬蜱阳性率高达96%，呼伦贝尔采集的全沟硬蜱阳性率为50%；巴彦淖尔采集的草原革蜱、边缘璃眼蜱以及呼伦贝尔采集的嗜群血蜱的混合样本阳性率分别为0%、28%与40%。
本研究明确了内蒙古地区蜱虫中CRT感染的高流行率，并首次在我国境内的边缘璃眼蜱中检测到CRT。内蒙古地区广泛的宿主范围与较高的感染率，可能大幅提升CRT对人类及其他脊椎动物的暴露风险。边缘璃眼蜱在立克次体病传播中的作用及其对公共卫生的潜在风险，有待进一步探究。