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Infection Prevalence of <i>Borrelia burgdorferi</i>in Ticks Collected from Songbirds in Far-Western Canada
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作者 John D. Scott lance a. durden John F. anderson 《Open Journal of Animal Sciences》 2015年第3期232-241,共10页
Worldwide, wild birds play a vital role in the dispersal of ticks that harbour tick-borne pathogens, including Borrelia burgdorferi, the Lyme disease bacterium. Using PCR testing, we found 124 (31%) of 405 ticks (4 sp... Worldwide, wild birds play a vital role in the dispersal of ticks that harbour tick-borne pathogens, including Borrelia burgdorferi, the Lyme disease bacterium. Using PCR testing, we found 124 (31%) of 405 ticks (4 species), which were collected from 21 species of birds in far-western Canada, to be infected with B. burgdorferi. Transstadial transmission of B. burgdorferi occurred from larva to nymph, plus nymph to adult, in the avian coastal tick, Ixodes auritulus, collected from songbirds in British Columbia (B.C). Collectively, all 3 motile life stages (larva, nymph, adult) of this tick had an infection prevalence of 31% for B. burgdorferi, which suggests vector competency. A Pacific Wren was highly infested with I. auritulus immatures, and 20 (44%) of 45 ticks (2 nymphs, 43 larvae) were infected with B. burgdorferi. This heavy infestation shows the high potential to initiate a new population of ticks and to disseminate Lyme spirochetes. Epidemiologically, B. burgdorferi-infected I. auritulus larvae collected from the Spotted Towhee, Swainson’s Thrush, Pacific Wren, and Fox Sparrow suggest that these avian hosts act as reservoirs for B. burgdorferi. In this study, the western blacklegged tick, Ixodes pacificus, and Ixodes spinipalpis played a limited role in the enzootic transmission cycle of B. burgdorferi along coastal B.C. We document the first record of I. spinipalpis on a bird in Alberta. Because songbirds widely disperse Lyme disease vector ticks, primary health providers and the general public must be vigilant that outdoors people may be bitten by B. burgdorferi-infected ticks throughout far-western Canada. 展开更多
关键词 TICKS IXODES auritulus IXODES pacificus IXODES spinipalpis Lyme Disease Borrelia BURGDORFERI SONGBIRD Bird Parasitism Infection Prevalence
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分子系统进化关系分析的一种新方法——贝叶斯法在硬蜱属中的应用 被引量:18
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作者 徐广 方庆权 +1 位作者 James E. KEIRaNS lance a. durden 《动物学报》 SCIE CAS CSCD 北大核心 2003年第3期380-388,共9页
距离矩阵邻接法、最大简约法和最大似然法是重建生物系统关系的 3种主要方法。普遍认为最大似然法在原理上优于前二种方法 ,但其计算复杂费时。由于现行计算机的能力尚达不到其要求而实用性差 ,特别是在处理大数据集样本 (即大于 2 5个... 距离矩阵邻接法、最大简约法和最大似然法是重建生物系统关系的 3种主要方法。普遍认为最大似然法在原理上优于前二种方法 ,但其计算复杂费时。由于现行计算机的能力尚达不到其要求而实用性差 ,特别是在处理大数据集样本 (即大于 2 5个分类单元 )时 ,用此方法几乎不可能。新近提出的贝叶斯法 (Bayesianmethod)既保留了最大似然法的基本原理 ,又引进了马尔科夫链的蒙特卡洛方法 ,并使计算时间大大缩短。本文用贝叶斯法对硬蜱属 (Ixodes) 19个种的线粒体 16SrDNA片段进行了系统进化分析。从总体上看 ,分析结果与现有的基于形态学的分类体系基本吻合。但与现存的假说相反 ,莱姆病的主要宿主蓖籽硬蜱复合种组并非单系。通过比较贝叶斯法与其它三种方法的结果 ,我们认为贝叶斯法是一种系统进化分析的好方法 ,它既能根据分子进化的现有理论和各种模型用概率重建系统进化关系 ,又克服了最大似然法计算速度慢、不适用于大数据集样本的缺陷。贝叶斯法根据后验概率直观地表示系统进化关系的分析结果 ,不需要用自引导法进行检验。可以预料 ,贝叶斯法将会被广泛地应用到系统进化分析上. 展开更多
关键词 分子系统进化 贝叶斯法 硬蜱属 线粒体 16SrDNA
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