Mărcuţan Ioan-Daniel, Kalmár Zsuzsa, Ionică Angela Monica, D'Amico Gianluca, Mihalca Andrei Daniel, Vasile Cozma, Sándor Attila D
Department of Parasitology and Parasitic Diseases, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Calea Mănăştur 3-5, Cluj Napoca, Romania.
Parasit Vectors. 2016 May 20;9(1):294. doi: 10.1186/s13071-016-1565-7.
Birds are important hosts and dispersers of parasitic arthropods and vector-borne zoonotic pathogens. Particularly migratory species may carry these parasites over long distances in short time periods. Migratory hotspots present ideal conditions to get a snapshot of parasite and pathogen diversity of birds migrating between continents. The aim of this study was to investigate the presence and diversity of Rickettsia spp. in ticks collected from birds at a migratory hot-spot in the Danube Delta, Romania, eastern Europe.
DNA was extracted from ticks that were collected from migratory birds in the Danube Delta during migratory seasons in 2011-2012. Two 360 bp fragments of the 16S ribosomal RNA gene and a 381 bp fragment Gene gltA were PCR amplified and analyzed by sequence analysis (performed at Macrogen Europe, Amsterdam, The Netherlands). Nucleotide sequences were compared to reference sequences available in the GenBank database, using Basic Local Alignment Search Tool.
Four hundred ticks of four different species were found on 11 bird species. The prevalence of Rickettsia spp. infection was 14 % (56/400, CI: 11.7-29.1), with significantly more nymphs hosting rickettsial infection compared to larvae (48 vs 7; P < 0.001). Significantly more ticks in nymphal stage were hosting Rickettsia spp. infection in spring, than in autumn. Four different genospecies were found: R. monacensis (29 ticks), R. helvetica (13), R. massiliae (3) and R. slovaca (2). The seasonal distribution of different Rickettsia spp. was heterogeneous; with most of the R. monacensis-infected ticks were found in spring, while more R. helvetica were found in autumn than spring. R. massiliae was found only in autumn and R. slovaca was found only in spring.
This study has shown that birds migrating through eastern Europe may carry ticks infected with a high diversity of rickettsial pathogens, with four Rickettsia spp. recorded. Migratory direction was important for pathogen burden, with seasonal differences in the occurrence of individual Rickettsia species. Here we report the first individual records of different Rickettsia spp. in H. concinna (R. monacensis), I. arboricola (R. helvetica, R. massiliae) and I. redikorzevi (R. helvetica) and also the first geographical record of occurrence of R. massiliae in Romania, representing the easternmost observation on the continent.
鸟类是寄生节肢动物和媒介传播人畜共患病原体的重要宿主和传播者。特别是候鸟可能在短时间内将这些寄生虫远距离携带。迁徙热点地区为了解在各大洲间迁徙鸟类的寄生虫和病原体多样性提供了理想条件。本研究的目的是调查罗马尼亚多瑙河三角洲（东欧）这个迁徙热点地区鸟类身上采集的蜱中是否存在立克次体属物种及其多样性。
从2011 - 2012年迁徙季节在多瑙河三角洲迁徙鸟类身上采集的蜱中提取DNA。对16S核糖体RNA基因的两个360bp片段和gltA基因的一个381bp片段进行PCR扩增，并通过序列分析（在荷兰阿姆斯特丹的Macrogen Europe公司进行）进行分析。使用基本局部比对搜索工具将核苷酸序列与GenBank数据库中可用的参考序列进行比较。
在11种鸟类身上发现了4种不同种类的400只蜱。立克次体属物种感染率为14%（56/400，置信区间：11.7 - 29.1），若虫感染立克次体的数量显著多于幼虫（48只对7只；P < 0.001）。春季若虫阶段感染立克次体属物种的蜱显著多于秋季。发现了4种不同的基因种：蒙纳立克次体（29只蜱）、瑞士立克次体（13只）、马赛立克次体（3只）和斯洛伐克立克次体（2只）。不同立克次体属物种的季节分布不均一；大多数感染蒙纳立克次体的蜱在春季被发现，而感染瑞士立克次体的蜱秋季比春季多。马赛立克次体仅在秋季被发现，斯洛伐克立克次体仅在春季被发现。
本研究表明，迁徙经过东欧的鸟类可能携带感染多种立克次体病原体的蜱，记录到了4种立克次体属物种。迁徙方向对病原体负荷很重要，不同立克次体物种的出现存在季节差异。在此我们报告了在康氏血蜱（蒙纳立克次体）、树栖革蜱（瑞士立克次体、马赛立克次体）和雷氏革蜱（瑞士立克次体）中不同立克次体属物种的首次个体记录，以及马赛立克次体在罗马尼亚出现的首次地理记录，这是在该大陆最东部的观察结果。
