Evaluating Effect of Woody Plant Encroachment on Tick-borne Pathogens in the South Central United States

评估美国中南部木本植物入侵对蜱传病原体的影响

• 批准号: 10452058
• 负责人: Scott Loss
• 金额: $ 7.27万
• 依托单位: OKLAHOMA STATE UNIVERSITY STILLWATER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-20 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10452058
• 关键词: Address; Affect; Amblyomma; Ambylomma americanum; Area; Arthropods; Biomass; Characteristics; Chronic Disease; Communities; Deer; Deforestation; Dermacentor; Disease; Domestic Animals; Ecology; Ecosystem; Ehrlichia; Ehrlichia chaffeensis; Ehrlichia ewingii; Ehrlichiosis; Environmental Impact; Foundations; Future; Goals; Grasslands; Health; Health Resources; Human; Humidity; Incidence; Individual; Infection; Influentials; Investigation; Juniperus virginiana; Kansas; Knowledge; Link; Lyme Disease; Microclimate; Modeling; Oklahoma; Outcome; Pattern; Personal Satisfaction; Pilot Projects; Plants; Prevalence; Public Health; Research; Rickettsia; Rickettsia Infections; Role; Sampling; Site; System; Tail; Temperature; Testing; Texas; Tick Control; Tick-Borne Diseases; Ticks; Trees; United States; Urbanization; Vector-transmitted infectious disease; Work; base; density; disorder risk; environmental change; forest; human disease; improved; innovation; land cover; non-Native; pathogen; spatiotemporal; spotted fever; tick-borne; tick-borne pathogen; transmission process; vector; vector tick; virtual

PROJECT SUMMARY/ABSTRACT The south-central U.S. has among the highest human incidences of tick-borne diseases (TbDs) like spotted fever group rickettsiosis and Ehrlichiosis. Yet, it is one of the least-studied regions with regard to the ecology of tick species and hosts, and their associations with human-caused environmental change. A pervasive form of human-caused land cover change ongoing globally, including in the south-central U.S., is encroachment of woody plants in grasslands and shrublands (woody plant encroachment; WPE). WPE’s ecological impacts (e.g., alteration of microclimates and arthropod communities) mirror mechanisms by which other land cover changes influence transmission of pathogens, including tick-borne pathogens (TbPs). However, WPE’s wholesale transformation of ecosystems makes it fundamentally different from other well-studied woody cover changes like deforestation and non-native shrub invasions in forests. A virtually unstudied consequence of WPE is its potential foundational role in influencing distributions of tick vectors and spatiotemporal patterns of TbP transmission. Our long-term goal is to clarify how WPE affects tick-borne diseases in the south-central U.S., and to apply this knowledge to better predict human disease risk and target public health resources and WPE management that benefit human health. Our overall aim is to assess relationships between WPE by eastern redcedar (ERC; Juniperus virginiana), the primary encroaching species in the south-central U.S, and TbP transmission systems in Oklahoma (where WPE extent is 5-7x greater than elsewhere in the U.S.). Our central hypothesis is that the many WPE-caused changes to ecosystems facilitate spatial expansion and persistence of key tick vectors and increase rates of vector infection for multiple pathogens. To address this hypothesis, we propose 2 objectives: 1) Quantify tick abundance and diversity relative to ERC encroachment; and 2) Evaluate links between TbP infection prevalence and ERC encroachment. Preliminary studies indicate that numbers of key tick species (Amblyomma americanum & Dermacentor variabilis), and of ticks infected with SFG rickettsia and Ehrlichia spp., are higher with ERC encroachment. This study will include 2 years of field sampling ticks at 40 sites representing 4 ERC encroachment stages, including control sites with no ERC. Ticks will be identified and tested for 5 pathogen groups, and we will analyze whether ERC stage is related to tick diversity, abundance, and TbP prevalence. This study is innovative because no research globally has considered effects of WPE under a whole-disease system framework. Addressing our objectives will increase understanding of WPE’s impact on ticks and TbP transmission dynamics; future research will address other mechanisms including WPE effects on reservoir hosts and tick-host interactions. This study will provide critical information that improves public health by informing tick control strategies based on assessment of land cover characteristics, and by focusing distribution of public health resources and enactment of WPE management.

项目概要/摘要 美国中南部是人类蜱传疾病 (TbD) 发病率最高的地区之一，例如斑点蜱传疾病 (TbD) 发热组立克次体病和埃利希体病。然而，它是关于生态学研究最少的地区之一。 蜱的种类和宿主，以及它们与人为环境变化的关系。一种普遍存在的形式 全球范围内，包括美国中南部，人为造成的土地覆盖变化正在侵蚀土地 草原和灌木丛中的木本植物（木本植物侵占；WPE）。 WPE 的生态影响 （例如，小气候和节肢动物群落的改变）反映了其他土地覆盖的机制 变化会影响病原体的传播，包括蜱传病原体 (TbP)。然而，WPE 的 生态系统的大规模转变使其与其他经过充分研究的木质覆盖物有着根本的不同 森林砍伐和非本地灌木入侵等变化。几乎未经研究的结果 WPE 是其在影响蜱虫向量分布和蜱虫时空模式方面的潜在基础性作用。 TbP传输。我们的长期目标是阐明 WPE 如何影响中南部地区的蜱传疾病 美国，并应用这些知识来更好地预测人类疾病风险并瞄准公共卫生资源和 WPE管理有利于人类健康。我们的总体目标是通过以下方式评估 WPE 之间的关系： 东部红杉（ERC；Juniperus virginiana），美国中南部的主要入侵物种，以及 俄克拉荷马州的 TbP 输电系统（该州的 WPE 范围比美国其他地方大 5-7 倍）。我们的 中心假设是，许多 WPE 引起的生态系统变化促进了空间扩张和 关键蜱虫媒介的持续存在并增加多种病原体的媒介感染率。为了解决这个问题 假设，我们提出 2 个目标：1）量化相对于 ERC 侵占的蜱丰度和多样性； 2) 评估 TbP 感染流行率与 ERC 侵占之间的联系。初步研究表明 关键蜱种（美洲钝蜱和变异革蜱）的数量以及感染蜱的数量 SFG 立克次体和埃利希体属，随着 ERC 的侵占而升高。这项研究将包括 2 年 代表 4 个 ERC 侵占阶段的 40 个地点的现场采样蜱，包括没有 ERC 的对照地点。 蜱虫将被识别并测试 5 种病原体组，我们将分析 ERC 阶段是否与 蜱的多样性、丰度和 TbP 流行率。这项研究具有创新性，因为全球范围内还没有研究 在整个疾病系统框架下考虑了 WPE 的影响。实现我们的目标将会增加 了解 WPE 对蜱虫和 TbP 传播动态的影响；未来的研究将解决其他问题 机制包括 WPE 对储存宿主的影响以及蜱与宿主的相互作用。这项研究将提供重要的 通过基于土地覆盖评估的蜱虫控制策略来改善公共卫生的信息 结合特点，重点配置公共卫生资源，制定WPE管理。