Revolutionising livestock tick-borne pathogen control

该项目将通过为主动管理提供知识和工具，彻底改变我们控制牲畜蜱虫和蜱传病原体的方式。蜱虫是一种吸血的寄生无脊椎动物，在世界范围内侵害脊椎动物。在全世界850种蜱虫中，非洲发现了150种，它们严重寄生在牲畜身上，并将一系列病原体传播给这些动物。在非洲，蜱传疾病是最重要的牲畜寄生虫和病原体之一，其中一些疾病每年造成的损失超过1.7亿美元。仅2018年以来，博茨瓦纳数万头牲畜的死亡与心水（反刍埃利希菌感染）有关。这直接影响到人类的粮食安全，从而影响到社区对全球变化的适应能力。气候变化、入侵蜱的传播和耐药性威胁着蜱和蜱传疾病的可持续控制。为了支持有效控制蜱传疾病，我们需要更好地了解推动TBP传播的过程。TBP传播模型是一种强大的工具，它使我们能够更好地了解该系统并评估环境和干预措施的影响，而这些影响在现场或体内试验中是不可能进行详细评估的。先前的研究主要采用一种蜱虫，一种病原体的方法，并且模型侧重于传播动力学的一个方面。然而，tps存在于更广泛的蜱虫共生群中，并存在于不断变化的环境中，这可能会影响传播。我最近进行的试点数据收集表明，在目前的SARS-CoV-2预防措施下，在现场收集蜱虫是可行的。这使我们能够在我们的研究区域博茨瓦纳对蜱虫进行公正的横断面调查，识别蜱虫（共生群）携带的所有细菌和原生动物，并将共生群的特征和结构与环境、兽医干预措施和疾病联系起来（工作包1；WP1）。然后，我们将开发并验证博茨瓦纳反刍杆菌传播的数学模型，通过调整和扩展北美莱姆病的现有模型，纳入共生菌群相互作用（WP2）。最后，我们将使用该模型评估潜在兽医和政策措施的流行病学影响，以制定博茨瓦纳控制TBP的指导方针（WP3）。这将是第一次真正公正的全国性TBP调查，也是非洲TBP传播的第一个综合模型。这个项目是新颖的，因为它不仅考虑了宿主-蜱-病原体的相互作用，而且考虑了蜱的共生群落和与环境的相互作用。最近在奥卡万戈三角洲爆发了毁灭性的蜱传疾病，这使得这个项目很及时，博茨瓦纳是理想的案例研究区域。我们将通过与兽医服务部的现有关系，与博茨瓦纳的决策者分享产出。我们将为兽医开发持续专业进修课程，让他们了解和实施项目成果，并可在一个专门的项目网站上查阅。这将扩大我们的潜在影响，超出我们的直接研究区域。所产生的所有数据和代码将以研究人员、兽医和政策制定者可访问的格式公开提供。

This project will revolutionise how we approach livestock tick and tick-borne pathogen (TBP) control by providing knowledge and tools for proactive management.Ticks are blood-feeding parasitic invertebrates that infest vertebrates worldwide. Of the >850 species of ticks worldwide, >150 are found in Africa, where they heavily parasitise livestock and are responsible for transmitting a range of pathogens to these animals. Tick-borne diseases are ranked among the most important livestock parasites and pathogens in Africa, and some are responsible for losses in excess of $170M/year. Heartwater (Ehrlichia ruminantium infection) has been implicated in the deaths of tens of thousands of livestock in Botswana since 2018 alone. This directly affects human food security and hence resilience of communities to global change. Climate change, spread of invasive ticks, and drug resistance threaten the sustainable control of ticks and tick-borne disease.To support effective control of tick-borne disease, we need to better understand the processes driving TBP transmission. Models of TBP transmission are powerful tools which allow us to better understand the system and evaluate the impact of environment and interventions which would not be possible to evaluate in detail in the field or with in vivo trials. Prior research has largely had a one-tick, one-pathogen approach, and models focussed on one aspect of transmission dynamics. However, TBPs exist within the wider tick symbiome, and in changing environments, which may affect transmission. Recent pilot data collection that I conducted demonstrated the feasibility of collecting ticks in the field under present SARS-CoV-2 prevention measures. This allows us to conduct an unbiased cross-sectional survey of ticks in our study region, Botswana, identify all bacteria and protozoa carried by the ticks (symbiome), and relate symbiome traits and structure to environment, veterinary intervention measures, and disease (Work Package 1; WP1). We will then develop and validate a mathematical model of E. ruminantium transmission in Botswana by adapting and extending an existing model developed for Lyme borreliosis in North America, incorporating symbiome interactions (WP2). Finally, we will use this model to evaluate the epidemiological impact of potential veterinary and policy measures, to develop guidelines for TBP control in Botswana (WP3). This will be the first truly unbiased, country-wide survey of TBPs, and the first comprehensive model of African TBP transmission. The project is novel as it considers not only host-tick-pathogen interactions, but also tick symbiome and interactions with the environment. Recent devastating outbreaks of tick-borne disease in the Okavango Delta make this project timely, and Botswana the ideal case study region.We will share outputs with policy makers in Botswana through our existing relationship with the Department of Veterinary Services. We will develop CPD modules for veterinarians to learn about and implement project output, accessible via a dedicated project website. This will extend our potential impact beyond our immediate study region. All data and code produced will be openly available in formats accessible to researchers, veterinarians and policy makers.