Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521, United States.
Ticks Tick Borne Dis. 2020 May;11(3):101359. doi: 10.1016/j.ttbdis.2019.101359. Epub 2019 Dec 14.
Use of emerging technology allowing for identification of genetic material from pathogens and endosymbionts in ticks collected from humans, domestic animals, wildlife, or the environment has resulted in an avalanche of new data on tick-microorganism associations. This rapidly growing stream of new information is a tremendous resource but also presents challenges, including how detection of pathogen genetic material in ticks should best be interpreted. There is a tendency in the more recent published literature to incorrectly use the term "vector" based on detection of pathogen genetic material from tick species not experimentally confirmed to serve as vectors of the pathogen in question. To serve as a vector of a horizontally maintained pathogen, such as a Borrelia burgdorferi sensu lato (s.l.) Lyme borreliosis spirochete, the tick species in question must be capable of acquiring the pathogen while feeding in the larval or nymphal stage on an infectious host, maintaining it transstadially through the molt, and then transmitting the pathogen to a naïve host while feeding in the subsequent nymphal or adult stage. This review examines the experimental evidence for and against species of hard (ixodid) ticks from different genera to serve as vectors of B. burgdorferi s.l. spirochetes. Of the 18 Ixodes species ticks evaluated to date, 13 were experimentally confirmed as vectors of B. burgdorferi s.l. spirochetes. These studies focused primarily on the three major Lyme borreliosis agents: Borrelia burgdorferi sensu stricto, Borrelia afzelii, and Borrelia garinii. In striking contrast, none of 8 tick species from other genera (1 Amblyomma species, 5 Dermacentor species, and 2 Haemaphysalis species) evaluated to date were unequivocally experimentally confirmed as vectors of B. burgdorferi s.l. spirochetes. The strength of the evidence for or against each tick species to serve as a vector of B. burgdorferi s.l. spirochetes is discussed together with key knowledge gaps and research challenges.
利用新兴技术，可以从人类、家畜、野生动物或环境中采集的蜱虫中鉴定出病原体和内共生体的遗传物质，这导致了蜱虫-微生物关联的大量新数据的出现。这一快速增长的信息流是一个巨大的资源，但也带来了挑战，包括如何最好地解释在蜱虫中检测到病原体遗传物质的含义。在最近发表的文献中，有一种倾向是错误地使用“载体”一词，因为从尚未经过实验证实可作为所研究病原体载体的蜱物种中检测到了病原体遗传物质。要作为一种水平维持的病原体（如 Borrelia burgdorferi sensu lato (s.l.) Lyme 螺旋体）的载体，所研究的蜱物种必须能够在幼虫或若虫阶段通过吸食感染宿主来获取病原体，在蜕皮过程中保持其跨期传播，并在随后的若虫或成虫阶段通过吸食将病原体传播给未感染的宿主。本综述检查了实验证据，以支持或反对不同属的硬蜱（Ixodid）物种作为 B. burgdorferi s.l. 螺旋体的载体。迄今为止，在评估的 18 种硬蜱物种中，有 13 种被实验证实为 B. burgdorferi s.l. 螺旋体的载体。这些研究主要集中在三种主要的莱姆病病原体上：Borrelia burgdorferi sensu stricto、Borrelia afzelii 和 Borrelia garinii。相比之下，迄今为止，在评估的 8 种来自其他属的蜱物种（1 种 Amblyomma 物种、5 种 Dermacentor 物种和 2 种 Haemaphysalis 物种）中，没有一种被明确实验证实为 B. burgdorferi s.l. 螺旋体的载体。讨论了每种蜱虫作为 B. burgdorferi s.l. 螺旋体载体的证据的强弱，并结合关键的知识差距和研究挑战进行了讨论。
