Comparative population genetics of two invading ticks: Evidence of the ecological mechanisms underlying tick range expansions

Two species of ixodid tick, Ixodes affinis Neumann and Amblyomma maculatum Koch, are simultaneously expanding their ranges throughout the mid-Atlantic region of the US. Although we have some understanding of the ecology and life history of these species, the ecological mechanisms governing where and how new populations establish and persist are unclear. To assess population connectivity and ancestry, we sequenced a fragment of the 16S mitochondrial rRNA gene from a representative sample of individuals of both species from populations throughout the eastern US. We found that despite overlapping host preferences throughout ontogeny, each species exhibited very different genetic and geographic patterns of population establishment and connectivity. I. affinis was of two distinct mitochondrial clades, with a clear geographic break separating northern and southern populations. Both I. affinis populations showed evidence of recent expansion, although the southern population was more genetically diverse, indicating a longer history of establishment. A. maculatum exhibited diverse haplotypes that showed no significant relationship with geographic patterns and little apparent connectivity between sites. Heteroplasmy was also observed in the 16S mitochondrial rRNA gene in 3.5% of A. maculatum individuals. Genetic evidence suggests that these species rely on different key life stages to successfully disperse into novel environments, and that host vagility, habitat stability and habitat connectivity all play critical roles in the establishment of new tick populations.     

CYTED Network to develop an immunogen compatible with integrated management strategies for tick control in cattle

INCOGARR is a thematic network recently approved to be financially supported by the Ibero-American Program of Science and Technology for Development (CYTED). The objectives of this Network are the design and evaluation of an efficient and feasible anti-tick vaccine candidate from the technical and economical points of view and also sharing experiences in the immunological control of ticks as part of an Integrated Control Program. The Network consists of seven laboratories and one company from six countries. The first meeting of the Network took place with the representation of each laboratory involved. In the meeting, general and specific objectives and activities of the Network were discussed and it was a very nice example of international collaboration to address an unsolved worldwide topic on tick control in which laboratories with different competencies and expertise join their efforts in a common goal.     

新发蜱媒传染病的国内外研究概况

蜱是一些人兽共患病的传播媒介和储存宿主,蜱媒传染病是虫媒传染病的重要组成部分。本文就国内外新发蜱媒传染病及其病原体研究热点进行扼要概述。     

吉林省延边地区蜱类分布及其携带发热伴血小板减少综合征病毒调查

本文旨在探讨吉林省延边地区自然环境和动物体表蜱类分布及其消长规律,掌握其携带发热伴血小板减少综合征布尼亚病毒(Severe fever with thrombocytopenia syndrome virus,SFTSV)状况及传播病毒能力。2016年4~9月份按月采集延边州所辖8个县(市)自然环境中生长的蜱虫和放牧动物体表蜱虫进行形态学分类,对其进行构成分析。对其中部分蜱虫分组进行SFTSV核酸检测。SFTSV核酸检测方法采用了Real time RT-PCR和RT-PCR相结合的方法。结果共采集蜱虫3 446只,其中森林革蜱763只,嗜群血蜱222只,日本血蜱639只,长角血蜱515只,全沟硬蜱1 014只,其他血蜱293只;全沟硬蜱(29.43%)和森林革蜱(22.14%)为本地优势种。长角血蜱在图们市(70.88%)和珲春市(40.59%)分布较多。对部分蜱虫(1605只)SFTSV Real time RT-PCR检测结果总最低感染率为1.81%,分种最低感染率分别为嗜群血蜱8.65%、日本血蜱4.53%、长角血蜱1.59%。序列分析结果表明,本文检测到的SFTSV病毒与我国其他省份从患者身上分离到的大部分SFTSV有高度一致性(99%)且与2012年从浙江患者血清中分离到的SFTSV、2013年韩国国家疾病预防控制中心从人身上采集的长角血蜱中分离到的SFTSV处于同一分枝,把该病毒命名为YBHC-TICK1-2016/CHINA。     

4种病原菌特异基因片段阳性蜱的16S rRNA基因克隆文库分析

Objective To develop the method of 16S rRNA gene clone library for tick bacterial flora analysis, and to analyze the detection effective of pathogens in tick and capacity of bacterial flora diversity. Methods Primers were designed according to the specific gene of Borrelia burgdorferi, Bartonella henselae, Anaplasma phagocytophilum, Ehrlichia chaffeensis and templates were choosen by positive PCR result to amplify the DNA extracted from the ticks. One set of primers targeting 16S rRNA gene conserved region were chosen to amplify certain fragments, DNA extraction, PCR reaction, cloning and sequencing. Nucleotide sequences were compared with GenBank database. Calculated Coverage values of clone library and Shannon-Wiener diversity index. Results Sixteen defined genus-or species-bacteria were detected in 103 valid sequences. Eight species were edge type (Clone No. > 5). Three kinds of pathogens were identified (Borrelia burgdorferi, Bartonella henselae and Rickettsia sp). Three kinds of pathogens were not edge type(Clone No. < 5). Coverage value was 96.11%, and Shannon-Wiener index was 2.40. Analysis results of cloning sequence showed that tick-parasitic bacteria mainly were α and γ deformation mycetes which accounted for 56.25% (9/16). Conclusions The 16S rRNA gene sequences technology could make relative quantitative of bacterial flora, and detect many kinds of pathogens in tick. It's a good method for detection of pathogens and bacterial flora analysis.     

4种病原菌特异基因片段阳性蜱的16S rRNA基因克隆文库分析

Objective To develop the method of 16S rRNA gene clone library for tick bacterial flora analysis, and to analyze the detection effective of pathogens in tick and capacity of bacterial flora diversity. Methods Primers were designed according to the specific gene of Borrelia burgdorferi, Bartonella henselae, Anaplasma phagocytophilum, Ehrlichia chaffeensis and templates were choosen by positive PCR result to amplify the DNA extracted from the ticks. One set of primers targeting 16S rRNA gene conserved region were chosen to amplify certain fragments, DNA extraction, PCR reaction, cloning and sequencing. Nucleotide sequences were compared with GenBank database. Calculated Coverage values of clone library and Shannon-Wiener diversity index. Results Sixteen defined genus-or species-bacteria were detected in 103 valid sequences. Eight species were edge type (Clone No. > 5). Three kinds of pathogens were identified (Borrelia burgdorferi, Bartonella henselae and Rickettsia sp). Three kinds of pathogens were not edge type(Clone No. < 5). Coverage value was 96.11%, and Shannon-Wiener index was 2.40. Analysis results of cloning sequence showed that tick-parasitic bacteria mainly were α and γ deformation mycetes which accounted for 56.25% (9/16). Conclusions The 16S rRNA gene sequences technology could make relative quantitative of bacterial flora, and detect many kinds of pathogens in tick. It's a good method for detection of pathogens and bacterial flora analysis.     

蜱杀虫剂的研究现状

蜱能传播多种疾病,对畜牧业造成严重损失。现有的蜱杀虫剂和疫苗均存在一定缺陷。本文对蜱杀虫剂,包括化学杀虫剂和非化学杀虫剂（中草药、纳米材料、病毒、真菌、细菌杀虫剂）的研究现状进行综述,分析现有蜱杀虫剂研究中的不足,以期为后续建立更高效、安全的蜱防控方法提供理论参考。     

50例森林脑炎患者治疗体会

目的通过对我院自2007至2010年收治的50例森林脑炎患者的临床资料回顾性分析,探讨该病的主要死亡原因。方法收治的50例患者中男性41例,女性9例,年龄17～60岁。平均年龄32.5岁,所有患者均生活在疫区,至少1次蜱叮咬史。潜伏期后出现典型临床表现,结合森林脑炎免疫荧光抗体阳性,及相关的辅助检查结果,除外其他中枢神经系统感染性疾病后诊断。结果本组50例患者,治愈38例,死亡7例,放弃治疗3例,遗留肢体运动障碍、智能减退、精神症状等后遗症者2例。结论森林脑炎病毒侵犯脑组织及脑干后引起的呼吸肌麻痹,呼吸机辅助呼吸可大大减少患者的病死率,以及积极地给予抗病毒、输注丙种球蛋白、防治脑水肿、预防肺内感染、维持水电解质平衡亦非常重要。提前接种森林脑炎疫苗,对于进入林区人员大有裨益。