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.

项目摘要/摘要 属于几个属的长子螨（Ascoschoengastia，Eutrombicula， Neotrombicula，Leptotrambidium等）表现出一种独特的寄生虫模式 到其他具有医学重要的节肢动物载体。特别是，瘦素属是 由Orientia tsutsugamushi（OT）引起的Scrub Typhus的独家生物学向量 强制性细胞内革兰氏阴性细菌与立克属密切相关 （立克西亚斯：立克西亚科）。这种疾病是发病率和 死亡;估计有十亿人处于危险之中，大约有100万案件是 每年报告。磨砂鼠伤寒发生在韩国，日本，整个南亚， 亚洲太平洋地区和北澳大利亚。最近，Scrub Typhus在 中东，智利南部和非洲已重塑了我们对 这种疾病的流行病学表明它具有更广泛的地理分布。尽管 越来越多的研究和发现的发现和发现 tsutsugamushi三角形，chi虫在人体感染中的作用 在美国仍然是一个未知的人。我们有从NC收集的Chiggers的初步数据 被立克种类感染。检查Chiggers Rickettsiae的患病率是 意义重大，因为美国的chi虫以与携带的tick虫相同的动物水库为食。 并传播人类疾病，人类疾病归因于 tick可能来自chi。在此提案中，我们将检测并确定患病率 来自不同啮齿动物物种的Chigger样品中的Rickettsiae DNA和自由生活 北卡罗来纳州的（未固定，寻求主机）的chi。另外，第一次调查 北卡罗来纳州chigger的细菌微生物组。这项研究将调查影响 宿主喂养与chigert病原体上的型式传播的相关性 带有特定螨和动物物种的细菌，以及裂缝之间的关系 微生物组组成，内共体相互作用和矢量能力。这 提案完全符合R03赠款计划的目标，评估健康风险 Chigger Bites的人类，这是一个完整的黑匣子（从未进行过 在美国之前）。在包括南美在内的其他大陆上的类似研究都有 发现chi以藏有人类病原体。