Obiegala Anna, Król Nina, Oltersdorf Carolin, Nader Julian, Pfeffer Martin
Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, An den Tierkliniken 1, 04103, Leipzig, Germany.
Department of Microbial Ecology and Environmental Protection, Institute of Genetics and Microbiology, University of Wrocław, Przybyszewskiego 63/77, 51-148, Wrocław, Poland.
Parasit Vectors. 2017 Mar 13;10(1):115. doi: 10.1186/s13071-017-2053-4.
Borrelia burgdorferi (sensu lato) and rickettsiae of the spotted fever group are zoonotic tick-borne pathogens. While small mammals are confirmed reservoirs for certain Borrelia spp., little is known about the reservoirs for tick-borne rickettsiae. Between 2012 and 2014, ticks were collected from the vegetation and small mammals which were trapped in Saxony, Germany. DNA extracted from ticks and the small mammals' skin was analyzed for the presence of Rickettsia spp. and B. burgdorferi (s.l.) by qPCR targeting the gltA and p41 genes, respectively. Partial sequencing of the rickettsial ompB gene and an MLST of B. burgdorferi (s.l.) were conducted for species determination.
In total, 673 small mammals belonging to eight species (Apodemus agrarius, n = 7; A. flavicollis, n = 214; Microtus arvalis, n = 8; Microtus agrestis, n = 1; Mustela nivalis, n = 2; Myodes glareolus, n = 435; Sorex araneus, n = 5; and Talpa europaea, n = 1) were collected and examined. In total, 916 questing ticks belonging to three species (Ixodes ricinus, n = 741; Dermacentor reticulatus, n = 174; and I. trianguliceps, n = 1) were collected. Of these, 474 ticks were further investigated. The prevalence for Rickettsia spp. and B. burgdorferi (s.l.) in the investigated small mammals was 25.3 and 31.2%, respectively. The chance of encountering Rickettsia spp. in M. glareolus was seven times higher for specimens infested with D. reticulatus than for those which were free of D. reticulatus (OR: 7.0; 95% CI: 3.3-14.7; P < 0.001). In total, 11.4% of questing I. ricinus and 70.5% of D. reticulatus were positive for Rickettsia spp. DNA of B. burgdorferi (s.l.) was detected only in I. ricinus (5.5%). Sequence analysis revealed 9 R. helvetica, 5 R. raoultii, and 1 R. felis obtained from 15 small mammal samples.
Small mammals may serve as reservoirs for Rickettsia spp. and B. burgdorferi (s.l.). While the prevalence for Rickettsia spp. in M. glareolus is most likely depending on the abundance of attached D. reticulatus, the prevalence for B. burgdorferi (s.l.) in small mammals is independent of tick abundance. Dermacentor reticulatus may be the main vector of certain Rickettsia spp. but not for Borrelia spp.
伯氏疏螺旋体（狭义）和斑点热群立克次体是由蜱传播的人畜共患病原体。虽然小型哺乳动物被确认为某些疏螺旋体物种的宿主，但对于蜱传播立克次体的宿主却知之甚少。2012年至2014年间，从德国萨克森州的植被和捕获的小型哺乳动物身上采集蜱虫。分别通过靶向gltA和p41基因的qPCR分析从蜱虫和小型哺乳动物皮肤中提取的DNA，以检测立克次体属和伯氏疏螺旋体（狭义）的存在。对立克次体ompB基因进行部分测序，并对伯氏疏螺旋体（狭义）进行多位点序列分型以确定物种。
总共收集并检查了属于8个物种的673只小型哺乳动物（黑线姬鼠，n = 7；黄颈姬鼠，n = 214；普通田鼠，n = 8；草原田鼠，n = 1；伶鼬，n = 2；林姬鼠，n = 435；欧洲鼩鼱，n = 5；欧洲鼹鼠，n = 1）。总共收集了属于3个物种的916只搜索蜱（蓖麻硬蜱，n = 741；网纹革蜱，n = 174；三角头硬蜱，n = 1）。其中，474只蜱被进一步研究。在所研究的小型哺乳动物中，立克次体属和伯氏疏螺旋体（狭义）的感染率分别为25.3%和31.2%。感染网纹革蜱的林姬鼠标本中遇到立克次体属的几率比未感染网纹革蜱的标本高7倍（比值比：7.0；95%置信区间：3.3 - 14.7；P < 0.001）。总共，11.4%的搜索蓖麻硬蜱和70.5%的网纹革蜱立克次体属DNA呈阳性。仅在蓖麻硬蜱中检测到伯氏疏螺旋体（狭义）的DNA（5.5%）。序列分析从15个小型哺乳动物样本中鉴定出9株瑞士立克次体、5株拉乌尔立克次体和1株猫立克次体。
小型哺乳动物可能是立克次体属和伯氏疏螺旋体（狭义）的宿主。虽然林姬鼠中立克次体属的感染率很可能取决于附着的网纹革蜱的数量，但小型哺乳动物中伯氏疏螺旋体（狭义）的感染率与蜱的数量无关。网纹革蜱可能是某些立克次体属的主要传播媒介，但不是疏螺旋体属的传播媒介。
