Tappe Julia, Strube Christina
Institute for Parasitology, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hanover, Germany.
Ticks Tick Borne Dis. 2013 Sep;4(5):432-8. doi: 10.1016/j.ttbdis.2013.04.009. Epub 2013 Jul 6.
The present study aimed to determine the prevalence of Rickettsiales (A. phagocytophilum and Rickettsia spp.) in 2100 I. ricinus ticks collected at 10 different sampling sites every month during the tick season 2010 in the city of Hanover, northern Germany. At the same time, the results served as a fifth-year-follow-up study to monitor whether changes or stagnation of tick infection rates - possibly due to climate change--were obvious or not. To detect infections with A. phagocytophilum and/or Rickettsia spp., tick samples were analysed by quantitative real-time PCR. Differentiation of Rickettsia species was accomplished using real-time pyrosequencing technology. Overall, 4.5% (94/2100) of the collected ticks were tested positive for A. phagocytophilum and 26.2% (551/2100) were positive for Rickettsia spp. infections. Species differentiation of Rickettsia-positive ticks via real-time pyrosequencing was possible in 48.6% (268/551) of samples, which were all identified as R. helvetica. Coinfections with both pathogens were found in 1.0% (20/2100) of ticks. Statistically significant seasonal fluctuations between sampling months as well as local differences between sampling sites were detected for Rickettsia spp. infection rates. For A. phagocytophilum infections, only significant seasonal variations were found. When comparing infection rates of Hanoverian ticks in 2010 to those in 2005, infection rates of A. phagocytophilum-infected nymphs increased statistically significant (P=0.008, power: 0.762) from 2.3% in 2005 (Schicht et al., 2011) to 4.5% in 2010. Rickettsia spp. infections in female ticks decreased significantly (P=0.049, power: 0.491) from 41.8% in 2005 (Schicht et al., 2012) to 32.4% in 2010. Comparison of the remaining tick stages showed no statistically significant differences.
本研究旨在确定2010年蜱虫季节期间，每月在德国北部汉诺威市的10个不同采样点采集的2100只蓖麻硬蜱中，立克次氏体（嗜吞噬细胞无形体和立克次氏体属）的感染率。同时，该结果作为一项为期五年的跟踪研究，以监测蜱虫感染率是否发生变化或停滞不前（可能由于气候变化所致）。为检测嗜吞噬细胞无形体和/或立克次氏体属的感染情况，通过定量实时聚合酶链反应（qPCR）对蜱虫样本进行分析。使用实时焦磷酸测序技术完成立克次氏体属物种的鉴别。总体而言，所采集的蜱虫中，4.5%（94/2100）的样本经检测呈嗜吞噬细胞无形体阳性，26.2%（551/2100）的样本呈立克次氏体属感染阳性。通过实时焦磷酸测序对立克次氏体阳性蜱虫进行物种鉴别，在48.6%（268/551）的样本中可行，所有这些样本均鉴定为瑞士立克次氏体。在1.0%（20/2100）的蜱虫中发现了两种病原体的混合感染。立克次氏体属的感染率在采样月份之间存在统计学上显著的季节性波动，以及采样点之间的局部差异。对于嗜吞噬细胞无形体感染，仅发现了显著的季节性变化。将2010年汉诺威蜱虫的感染率与2005年的进行比较时，嗜吞噬细胞无形体感染若虫的感染率从2005年的2.3%（施希特等人，2011年）上升至2010年的4.5%，具有统计学显著性（P = 0.008，检验效能：0.762）。雌性蜱虫中立克次氏体属的感染率从2005年的41.8%（施希特等人，2012年）显著下降至2010年的32.4%（P = 0.049，检验效能：0.491）。对其余蜱虫阶段的比较未显示出统计学上的显著差异。
