Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
Parasit Vectors. 2013 Jul 19;6:212. doi: 10.1186/1756-3305-6-212.
Spotted fever group (SFG) rickettsiae have recently been identified for the first time in UK ticks. This included the findings of Rickettsia helvetica in Ixodes ricinus and Rickettsia raoultii in Dermacentor reticulatus. This paper further investigates the occurrence of SFG rickettsiae in additional geographically distinct populations of D. reticulatus, and for the first time, investigates the occurrence of SFG rickettsiae in UK populations of Haemaphysalis punctata ticks.
Questing D. reticulatus and H. punctata were collected at a number of sites in England and Wales. DNA from questing ticks was extracted by alkaline lysis and detection of rickettsiae DNA was performed, in addition to detection of A. phagocytophilum, N. mikurensis, C. burnetii and B. burgdorferi sensu lato.
This paper builds on previous findings to include the detection of spotted fever Rickettsia which showed the highest homology to Rickettsia massiliae in Haemaphysalis punctata, as well as R. helvetica in D. reticulatus. The occurrence of SFG rickettsiae in D. reticulatus in the UK appears to be confined only to Welsh and Essex populations, with no evidence so far from Devon. Similarly, the occurrence of SFG rickettsiae in H. punctata appears confined to one of two farms known to be infested with this tick in North Kent, with no evidence so far from the Sussex populations. Anaplasma phagocytophilum, Neoehrlichia mikurensis, Coxiella burnetii and Borrelia burgdorferi sensu lato DNA was not detected in any of the ticks.
These two tick species are highly restricted in their distribution in England and Wales, but where they do occur they can be abundant. Following detection of these SFG rickettsiae in additional UK tick species, as well as I. ricinus, research should now be directed towards clarifying firstly the geographic distribution of SFG rickettsiae in UK ticks, and secondly to assess the prevalence rates in ticks, wild and domesticated animals and humans to identify the drivers for disease transmission and their public health significance.
斑点热群（SFG）立克次体最近在英国的蜱虫中首次被发现。这包括在硬蜱和网纹革蜱中发现的赫尔尼亚立克次体和拉乌尔立克次体。本文进一步调查了 SFG 立克次体在地理上不同的网纹革蜱种群中的发生情况，并且首次调查了 SFG 立克次体在英国的血红扇头蜱种群中的发生情况。
在英格兰和威尔士的多个地点收集了活动的网纹革蜱和血红扇头蜱。通过碱性裂解提取活动蜱的 DNA，并进行了立克次体 DNA 的检测，此外还检测了嗜吞噬细胞无形体、嗜吞噬细胞无形体、伯氏疏螺旋体和伯氏疏螺旋体。
本文在前人的研究基础上进一步发现，在血红扇头蜱中检测到的斑点热立克次体与马赛立克次体具有最高的同源性，在网纹革蜱中检测到的立克次体与赫尔尼亚立克次体具有最高的同源性。在英国，网纹革蜱中 SFG 立克次体的发生似乎仅限于威尔士和埃塞克斯的种群，目前尚无德文郡的证据。同样，在北肯特郡的两个已知有这种蜱虫出没的农场中发现了 SFG 立克次体在血红扇头蜱中的发生，但目前还没有来自苏塞克斯郡的证据。在任何蜱虫中都未检测到嗜吞噬细胞无形体、嗜吞噬细胞无形体、贝氏柯克斯体和伯氏疏螺旋体。
这两种蜱在英格兰和威尔士的分布非常有限，但在它们存在的地方，它们可能非常丰富。在英国的其他蜱种以及硬蜱中检测到这些 SFG 立克次体后，现在应将研究方向首先明确 SFG 立克次体在英国蜱中的地理分布，其次评估蜱、野生动物和家养动物以及人类中的流行率，以确定疾病传播的驱动因素及其公共卫生意义。
