First detection of rickettsiae in a US chigger population and the potential risk to people

项目摘要/摘要 隶属于几个属(Ascoschoengastia，Eutrombcula，Eutrombcula， Neotrombcula、Leptotrombidium等)展示了一种比较独特的寄生模式 其他医学上重要的节肢动物病媒。特别是，细粒藻属是 由东方体(OT)引起的独特的斑疹伤寒生物媒介。 与立克次体密切相关的专性胞内革兰氏阴性细菌 (立枯菌目：立枯菌科)。这种疾病是发病率和 死亡率；估计有10亿人处于危险之中，大约100万病例是 每年都有报告。丛林斑疹伤寒在韩国、日本、整个南亚、 亚太地区和澳大利亚北部。最近，丛林斑疹伤寒在 中东、智利南部和非洲重塑了我们对 这种疾病的流行病学，表明它有更广泛的地理分布。尽管 在国外对恙螨传播的人类疾病的研究和发现越来越多 钩体在人感染立克次体病原体中的作用 在美国还完全是个未知数。我们有姬鼠从北卡罗来纳州收集的初步数据 都感染了立克次体。检查立克次体在立克次体中的流行情况 这一点很重要，因为美国的吸虫与携带扁虱的动物以相同的动物水库为食 并传播人类疾病，人类疾病有可能归因于 扁虱可能来自蟋蟀。在这份提案中，我们将检测和确定流行率 不同鼠种和自由生活人群恙螨标本中立克次体DNA的检测 北卡罗来纳州(无食物、寻找寄主的)恙虫。另外，第一次调查 北卡罗来纳州恙虫的细菌微生物群。这项研究将调查其影响 恙螨病原体上寄主摄食与经卵巢传播的关系 细菌与特定的螨类和动物种类，以及恙螨之间的关系 微生物群组成、内共生菌相互作用和媒介能力。这 建议完全符合R03赠款计划的目标，评估 人咬恙螨，这是一个完全的黑匣子(从未进行过 在美国之前)。在包括南美在内的其他大陆上进行的类似研究， 发现吸虫是人类病原体的庇护所。

Project Summary/Abstract Trombiculid mites belonging to several genera (Ascoschoengastia, Eutrombicula, Neotrombicula, Leptotrombidium, etc.) demonstrate a unique mode of parasitism compared to other medically important arthropod vectors. Particularly, the genus Leptotrombidium is the exclusive biological vector of scrub typhus, caused by Orientia tsutsugamushi (Ot), an obligate intracellular Gram-negative bacterium closely related to the genus Rickettsia (Rickettsiales: Rickettsiaceae). This disease is a significant source of morbidity and mortality; an estimated billion people are at risk and approximately one million cases are reported each year. Scrub typhus occurs in Korea, Japan, throughout southern Asia, the Asian-Pacific region, and northern Australia. More recently, scrub typhus reports in the Middle East, southern Chile, and Africa have reshaped our thinking about the epidemiological of this disease, suggesting it has a wider geographical distribution. Despite the growing number of studies and discoveries of chigger-borne human disease outside of the Tsutsugamushi Triangle, the role of chiggers in human infection of rickettsial pathogens in the US is still a total unknown. We have preliminary data that chiggers collected from NC are infected with Rickettsia species. Examining the prevalence of rickettsiae in chiggers is significant because chiggers in the US feed on the same animal reservoirs as ticks that carry and transmit human diseases, and there is the potential that human diseases attributed to ticks might be from chiggers. In this proposal, we will detect and determine the prevalence of rickettsiae DNA in chigger samples from different rodent species and for free-living (unfed, host-seeking) chiggers in North Carolina. Also, investigate for the first time the bacterial microbiome of chiggers in the North Carolina. This study will investigate the impact of host feeding versus transovarial transmission on the chigger pathogen, the association of bacteria with specific mite and animal species, and the relationship between chigger microbiome composition, endosymbiont interactions, and vector competency. This proposal exactly fits the goal of the R03 grants program, assessing the health risk to humans of chigger bites, which is a complete black box (has never been conducted before in the US). Similar studies on other continents, including South America, have found chiggers to harbor human pathogens.