Schwan T G
Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA.
Infect Agents Dis. 1996 Jun;5(3):167-81.
Blood-feeding arthropods transmit numerous types of infectious agent and parasite that have a tremendous impact on human health and mortality throughout the world. These vector-borne pathogens display a wide array of evolutionary patterns that allow them to infect and to be successfully transmitted by ticks, mites, and hematophagous insects. The vector's method of feeding, type of development, and host preference are also critical factors for the transfer of zoonotic agents from wild animal reservoirs to susceptible humans. Ticks are obligate blood-feeders in all life stages and biologically transmit many infectious agents. In North America, two ticks that are involved in the maintenance and transmission of pathogenic spirochetes include Ixodes scapularis (family Ixodidae) and Ornithodoros hermsi (family Argasidae). These ticks are the respective vectors of the Lyme disease spirochete Borrelia burgdorferi and a relapsing fever spirochete, Borrelia hermsii. Little is known concerning how these and related species of Borrelia adapt to successfully alternate between warm-blooded vertebrates and ticks; however, the possibility that borrelial surface proteins are differentially expressed in their different hosts is an exciting area of current research.
吸食血液的节肢动物传播多种类型的传染原和寄生虫，这些对全世界人类健康和死亡率有着巨大影响。这些媒介传播的病原体呈现出各种各样的进化模式，使它们能够感染蜱、螨和吸血昆虫，并通过这些媒介成功传播。媒介的进食方式、发育类型和宿主偏好也是人畜共患病原体从野生动物宿主传播给易感人类的关键因素。蜱在所有生命阶段都是专性吸血者，能生物性传播许多传染原。在北美，参与致病性螺旋体维持和传播的两种蜱包括肩突硬蜱（硬蜱科）和赫氏钝缘蜱（钝缘蜱科）。这些蜱分别是莱姆病螺旋体伯氏疏螺旋体和回归热螺旋体赫氏疏螺旋体的传播媒介。关于这些以及相关的疏螺旋体物种如何成功地在温血脊椎动物和蜱之间交替适应，人们所知甚少；然而，疏螺旋体表面蛋白在其不同宿主中差异表达的可能性是当前研究中一个令人兴奋的领域。
