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

首次在美国恙螨种群中发现立克次体及其对人类的潜在风险

• 批准号: 10516083
• 负责人: Loganathan Ponnusamy
• 金额: $ 7.53万
• 依托单位: NORTH CAROLINA STATE UNIVERSITY RALEIGH
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10516083
• 关键词: Acari; Adult; Africa; Animals; Antibodies; Arthropod Vectors; Asian; Australia; Bacteria; Binding; Biological; Bite; Case Study; Cause of Death; Chiggers; Chile; Classification; Cotton Rats; DNA; Data; Dermatitis; Detection; Disease; Disease Outbreaks; Disease Vectors; Environment; Epidemiology; Eutrombicula; Geographic Distribution; Goals; Gram-Negative Bacteria; Grant; Health; Horizontal Disease Transmission; Human; Human Bites; Immunofluorescence Immunologic; Island; Japan; Korea; Laboratories; Larva; Leptotrombidium; Life Cycle Stages; Mammals; Medical; Middle East; Mites; Morbidity - disease rate; Mothers; Neotrombicula; North Carolina; Nymph; Orientia tsutsugamushi; Pain; Patients; Persons; Pilot Projects; Population; Populations at Risk; Prevalence; Process; Public Health; Reporting; Research; Rickettsia; Rickettsia Infections; Rickettsia conorii; Rickettsia felis; Rickettsia rickettsii; Rickettsiaceae; Risk; Rocky Mountain Spotted Fever; Rodent; Role; Sampling; Scrub Typhus; Shapes; Source; South America; Southern Asia; System; Testing; Thinking; Ticks; Time; Trombicula; Trombiculiasis; United Arab Emirates; United States; Vector-transmitted infectious disease; Vertebrates; Visit; Wild Animals; bacteriome; cross reactivity; egg; endosymbiont; feeding; health assessment; human disease; human pathogen; microbiome; microbiome composition; mortality; novel; parasitism; pathogen; pathogenic bacteria; programs; saliva secretion; spotted fever; tick bite; tick transmission; tick-borne; transmission process; vector; vector competence

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.

项目总结/摘要 恙螨属于几个属（Ascoschoengastia，Eutrobicula， 新恙螨属、纤恙螨属等）证明了一种独特的寄生模式， 其他医学上重要的节肢动物媒介。特别地，纤恙螨属是 恙虫病东方体（Ot）是恙虫病的唯一生物媒介， 与立克次体属密切相关的专性细胞内革兰氏阴性细菌 （立克次体目：立克次体科）。这种疾病是发病率的重要来源， 死亡率;估计有10亿人处于危险之中，大约有100万例 每年报告。恙虫病发生在韩国，日本，整个南亚， 亚太地区和澳大利亚北方。最近，丛林斑疹伤寒报告， 中东、智利南部和非洲重新塑造了我们对 这种疾病的流行病学，这表明它有更广泛的地理分布。尽管 越来越多的研究和发现，恙螨传播的人类疾病以外的 恙虫病三角区，恙螨在人类感染立克次体病原体中的作用 在美国仍然是一个未知数。我们有恙螨从北卡罗来纳州收集的初步数据 都感染了立克次体检查恙螨立克次体的流行情况是 重要的是，美国的恙螨以携带蜱虫的相同动物宿主为食， 并传播人类疾病，人类疾病有可能归因于 蜱虫可能来自恙螨。在本提案中，我们将检测和确定 不同啮齿类恙螨样本中立克次体DNA的含量 （饥饿的，寻找宿主的）北卡罗来纳州的恙螨。此外，首次调查 北卡罗来纳州恙螨的细菌微生物组。本研究将调查 宿主进食与恙螨病原体跨卵传播的关系， 细菌与特定螨类及动物种、恙螨的关系 微生物组组成、内共生体相互作用和载体能力。这 该提案完全符合R 03赠款计划的目标，评估健康风险， 人类的恙螨叮咬，这是一个完整的黑匣子（从来没有进行过 在美国之前）。在包括南美洲在内的其他大陆进行的类似研究， 发现恙螨携带人类病原体