Department of Virology and Immunology, National Institute for Health Development, Tallinn, Estonia.
Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia.
Parasit Vectors. 2021 Jan 20;14(1):65. doi: 10.1186/s13071-020-04564-7.
Rickettsia spp. are human pathogens that cause a number of diseases and are transmitted by arthropods, such as ixodid ticks. Estonia is one of few regions where the distribution area of two medically important tick species, Ixodes persulcatus and I. ricinus, overlaps. The nidicolous rodent-associated Ixodes trianguliceps has also recently been shown to be present in Estonia. Although no data are available on human disease(s) caused by tick-borne Rickettsia spp. in Estonia, the presence of three Rickettsia species in non-nidicolous ticks has been previously reported. The aim of this study was to detect, identify and partially characterize Rickettsia species in nidicolous and non-nidicolous ticks attached to rodents in Estonia.
Larvae and nymphs of I. ricinus (n = 1004), I. persulcatus (n = 75) and I. trianguliceps (n = 117), all removed from rodents and shrews caught in different parts of Estonia, were studied for the presence of Rickettsia spp. by nested PCR. Ticks were collected from 314 small animals of five species [Myodes glareolus (bank voles), Apodemus flavicollis (yellow necked mice), A. agrarius (striped field mice), Microtus subterranius (pine voles) and Sorex araneus (common shrews)]. Rickettsial DNA was detected in 8.7% (103/1186) of the studied ticks. In addition to identifying R. helvetica, which had been previously found in questing ticks, we report here the first time that the recently described I. trianguliceps-associated Candidatus Rickettsia uralica has been identified west of the Ural Mountains.
立克次体是人畜共患病原体，可引起多种疾病，并通过节肢动物（如硬蜱）传播。爱沙尼亚是少数几种两种医学上重要的蜱种（即 Ixodes persulcatus 和 I. ricinus）分布区重叠的地区之一。最近还发现，寄生在啮齿动物上的伊氏革蜱也存在于爱沙尼亚。尽管目前尚无关于爱沙尼亚蜱传立克次体引起的人类疾病的数据，但以前曾报道过非寄生蜱中存在三种立克次体。本研究旨在检测、鉴定和部分描述附着在爱沙尼亚啮齿动物和鼩鼱上的寄生和非寄生蜱中的立克次体种类。
从在爱沙尼亚不同地区捕获的啮齿动物和鼩鼱身上采集的幼虫和若虫的 I. ricinus（n=1004）、I. persulcatus（n=75）和 I. trianguliceps（n=117）中，通过巢式 PCR 检测到立克次体。共采集了来自五个物种的 314 只小动物（林姬鼠、黑线姬鼠、黑线仓鼠、欧洲鼩鼱和普通鼩鼱）的蜱。研究了 1186 只蜱中的 8.7%（103/1186）检测到立克次体 DNA。除了鉴定以前在游离蜱中发现的 R. helvetica 外，我们还首次报告了最近描述的与伊氏革蜱相关的候选立克次氏体 Candidatus Rickettsia uralica 在乌拉尔山脉以西被发现。
