Relapsing fever (RF) is caused by several species of Borrelia; all, except two species, are transmitted to humans by soft (argasid) ticks. The species B. recurrentis is transmitted from one human to another by the body louse, while B. miyamotoi is vectored by hard-bodied ixodid tick species. RF Borrelia have several pathogenic features that facilitate invasion and dissemination in the infected host. In this article we discuss the dynamics of vector acquisition and subsequent transmission of RF Borrelia to their vertebrate hosts. We also review taxonomic challenges for RF Borrelia as new species have been isolated throughout the globe. Moreover, aspects of pathogenesis including symptomology, neurotropism, erythrocyte and platelet adhesion are discussed. We expound on RF Borrelia evasion strategies for innate and adaptive immunity, focusing on the most fundamental pathogenetic attributes, multiphasic antigenic variation. Lastly, we review new and emerging species of RF Borrelia and discuss future directions for this global disease.

中文翻译：

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回归热的发病机制。

回归热 (RF) 是由几种疏螺旋体引起的；除两个物种外，所有物种都通过软（argasid）蜱传播给人类。B.recurrentis物种通过体虱从一个人传播到另一个人，而B.miyamotoi由硬体硬蜱物种传播。RF Borrelia具有多种致病特征，可促进受感染宿主的入侵和传播。在本文中，我们讨论了 RF疏螺旋体向其脊椎动物宿主的矢量采集和随后传输的动力学。我们还回顾了 RF Borrelia的分类挑战因为新物种已在全球范围内被隔离。此外，还讨论了发病机制的各个方面，包括症状、神经嗜性、红细胞和血小板粘附。我们阐述了先天性和适应性免疫的 RF疏螺旋体逃避策略，重点关注最基本的致病属性，多相抗原变异。最后，我们回顾了新出现的 RF Borrelia物种，并讨论了这种全球疾病的未来发展方向。