BORRELIA EVOLUTION AND POPULATION STRUCTURE

提出的项目旨在深入了解伯氏疏螺旋体病原体与其各自人畜共患病的脊椎动物宿主和节肢动物媒介之间的相互作用和联系。为了充分表征伯氏疏螺旋体自然种群的结构，有必要从其不同层次的组织中取样，以确定决定伯氏疏螺旋体分离株分布和交换性的时间、地理和宿主环境因素。这种抽样的地理要求通过使用沿海岛屿得到满足，选择这些岛屿的独特品质使其成为跟踪新发疾病生态动态的理想天然实验室。这两个地点的时间抽样是纵向的（在研究的每一年对每个岛屿进行两年一次的抽样），以及在不重叠的年度周期中对蜱虫群进行横断面抽样。宿主环境之间的关系可以直接测试，因为分离的伯氏疏螺旋体是直接从它们的宿主收集的。将确定每个岛屿站点（和每个时间点）分离的所有小鼠、蜱和伯氏疏螺旋体的多位点基因型，从而为评估其各自种群的结构以及这些物种之间的相互作用提供丰富的资源。

The proposed project is designed to gain insight to the interactions and associations between Borrelia pathogens and their respective zoonotic vertebrate reservoirs and arthropod vectors. To fully characterize the structure of natural populations of B. burgdorferi, it is necessary to sample isolates from the various levels of its organization to determine the temporal, geographic, and host environmental factors which determine the distribution and exchangeability among B. burgdorferi isolates. Thes geographic requirements of this sampling are met by the use of coastal islands, which have been chosen for the unique qualities that make them ideal natural laboratories for tracking the ecological dynamics of emerging disease. The temporal sampling of these two sites is accomplished both longitudinally (by sampling each islands bi- annually for each year of the study), and by cross-sectional sampling of the tick cohorts in non-overlapping annual cycle. The relationship between the host environments can be tested directly, since the Borrelia isolates are collected directly from their hostsj. The multi-locus genotypes of all mice, ticks, and Borrelia isolates from each island site (and at each time point) will be determined, thus providing a rich resource for evaluating the structure of their respective populations, and the interactions among these species.