Ye Xiaodong, Sun Yi, Ju Wendong, Wang Xin, Cao Wuchun, Wu Mingyu
State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology & Epidemiology, No. 20 Dongdajie Str. Fengtai District, Beijing, People Republic of China.
Centre for Disease Control and Prevention of Jindong, No.295 Jiangjun Road, Jinhua, Zhejiang province, People Republic of China.
Parasit Vectors. 2014 Nov 19;7:512. doi: 10.1186/s13071-014-0512-8.
Cases of Mediterranean Spotted Fever like rickettsioses, caused by Rickettsia monacensis, have become more common in the last 10 years. In China, natural infection of R. monacensis in various tick species has been confirmed but the vector(s) of R. monacensis have not been recorded.
The prevalence of R. monacensis in >1500 Ixodidae ticks from central and southern China was determined using centrifugation-shell vial culture and polymerase chain reaction techniques. The predominant species, Ixodes sinensis, harbored a natural infection of R. monacensis and was assumed to be a vector candidate of R. monacensis. Experimental transmissions were initialized by infecting Rickettsia-free tick colonies with R. monacensis using capillary tube feeding (CTF) or immersion techniques. Transstadial and transovarial transmissions, and transmission from ticks to mice, were conducted under laboratory conditions.
R. monacensis was isolated and identified from hemolymph of Ixodes sinensis using molecular techniques. Transovarial transmission of R. monacensis from infected ♀I. sinensis to offspring was documented and infected offspring successfully passed Rickettsia to mice. Transstadial transmission rates were 58% in larva to nymph and 56% in nymph to adult stages. Infected nymphs and adults were also able to infect mice.
I. sinensis is a competence vector for R. monacensis as demonstrated by natural infection and transmission studies.
由蒙氏立克次体引起的类地中海斑疹热立克次体病病例在过去10年中变得更加常见。在中国，已证实多种蜱虫中存在蒙氏立克次体的自然感染，但尚未记录到蒙氏立克次体的传播媒介。
使用离心管瓶培养和聚合酶链反应技术，测定了来自中国中部和南部的1500多只硬蜱科蜱虫中蒙氏立克次体的流行情况。优势种中华硬蜱自然感染了蒙氏立克次体，被认为是蒙氏立克次体的潜在传播媒介。通过用毛细管喂食（CTF）或浸泡技术用蒙氏立克次体感染无立克次体的蜱虫群落来启动实验性传播。在实验室条件下进行跨龄期和经卵传播，以及从蜱虫到小鼠的传播。
使用分子技术从中华硬蜱的血淋巴中分离并鉴定出蒙氏立克次体。记录了蒙氏立克次体从受感染的中华硬蜱雌虫到后代的经卵传播，并且受感染的后代成功地将立克次体传播给了小鼠。从幼虫到若虫的跨龄期传播率为58%，从若虫到成虫阶段的传播率为56%。受感染的若虫和成虫也能够感染小鼠。
自然感染和传播研究表明，中华硬蜱是蒙氏立克次体的有效传播媒介。
