With one exception (epidemic relapsing fever), borreliae are obligately maintained in nature by ticks. Although some Borrelia spp. may be vertically transmitted to subsequent generations of ticks, most require amplification by a vertebrate host because inheritance is not stable. Enzootic cycles of borreliae have been found globally; those receiving the most attention from researchers are those whose vectors have some degree of anthropophily and, thus, cause zoonoses such as Lyme disease or relapsing fever. To some extent, our views on the synecology of the borreliae has been dominated by an applied focus, viz., analyses that seek to understand the elements of human risk for borreliosis. But, the elements of borrelial perpetuation do not necessarily bear upon risk, nor do our concepts of risk provide the best structure for analyzing perpetuation. We identify the major global themes for the perpetuation of borreliae, and summarize local variations on those themes, focusing on key literature to outline the factors that serve as the basis for the distribution and abundance of borreliae.

中文翻译：

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伯氏疏螺旋体的永久存在。

除一种例外（流行性回归热）外，疏螺旋体在自然界中必然由蜱虫维持。尽管有些伯氏疏螺旋体属（Borrelia spp.）。可能会垂直传播给后代的蜱，大多数需要脊椎动物宿主放大，因为遗传不稳定。全球范围内都发现了伯氏疏螺旋体的地方性循环；最受研究人员关注的是那些载体具有一定程度的人性化并因此导致莱姆病或回归热等人畜共患疾病的载体。在某种程度上，我们对伯氏疏螺旋体的协同学的看法一直以应用为主导，即寻求了解人类伯氏疏螺旋体病风险要素的分析。但是，疏螺旋体永存的要素并不一定与风险有关，我们的风险概念也没有提供分析永存的最佳结构。我们确定了伯氏疏螺旋体永久存在的主要全球主题，并总结了这些主题的当地差异，重点关注关键文献，概述了伯氏疏螺旋体分布和丰度基础的因素。