Combining molecular biology and computer modelling to enhance control of liver fluke in livestock across agricultural landscapes

结合分子生物学和计算机建模，加强对农业领域牲畜肝吸虫的控制

• 批准号: 2750173
• 金额: --
• 依托单位: Aberystwyth University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2750173
• 关键词: Combining; molecular; biology; computer; modelling

Liver fluke (Fasciola hepatica) is a highly pathogenic trematode parasite that is highly prevalent in cattle and sheep globally, with its disease, fasciolosis estimated to cost European livestock producers over £2 billion annually. Climate change and anthelmintic resistance are driving increasing liver fluke prevalence globally. This increase in prevalence is seriously impacting animal health, welfare and productivity, and threatening the sustainability of livestock production in certain regions.To alleviate this threat, and to sustainably manage liver fluke in future decades, alternative non-chemical control strategies are required. These alternative strategies may target the F. hepatica lifecycle, which revolves around an intermediate snail host (Galba truncatula). This snail is only present in areas on pastureland where optimal environmental and microclimatic conditions allow it to thrive. Strategies including grazing rotation, temporary or permanent fencing of risk areas and targeted treatment of livestock to reduce pasture contamination of F. hepatica eggs can impede the lifecycle. However, major barriers prevent the mass adoption of these alternative control strategies. Poor understanding of the spatial distribution G. truncatula habitats on farms impedes on the ability of farmers to successfully apply measures targeting the snail. There is also limited information regarding how these alternative strategies can be optimally applied, including which periods of the year they should be employed and for how long.In recent years, the project's supervisory team have developed novel research tools that allow researchers to investigate the epidemiology of G. truncatula and F. hepatica at field level. These include the development of environmental DNA assays which can identify the presence of G. truncatula on farmland (Jones et al., 2018), and mechanistic modelling techniques which can accurately model F. hepatica infection risk over time at farm level (Beltrame et al., 2018). This project aims to utilise these tools to develop and evaluate farm specific guidance for successful application of non-chemical control methods for F. hepatica control on UK farms.During the PhD programme, the prospective student will evaluate and compare a range of DNA extraction methods and molecular tools to identify optimal methodology for G. truncatula eDNA capture, extraction and amplification. The optimal methodologies identified will then be applied to survey G. truncatula habitats on multiple UK farms. Environmental and climatic measurements will also be gathered in these sampling sites and analysed in conjunction with eDNA survey results to identify factors associated with the presence of G. truncatula snails in water-saturated habitats on farmland. Finally, mechanistic models will evaluate the impact of grazing rotations, temporary and permanent fencing of G. truncatula habitats and targeted treatment to minimise pasture contamination of fluke eggs on future F. hepatica infection risk in grazing livestock on farms studied and mapped via eDNA survey. These models will also evaluate the optimal timeframe for the application of these strategies, how weather interacts with farm topography and structure to affect their success, and how pasture architecture can be altered to enhance impact of grazing-based control, for fluke and co-infecting nematode parasites.The prospective student will acquire inter-disciplinary skills in molecular biology, parasitology, computational modelling and generic research methods and communication. Specifically, the prospective student will develop skills to perform a range of DNA extraction and amplification methodologies, to morphologically identify intermediate snail host and parasite life stages and to develop and apply mechanistic models. Training will be provided by the supervisory team and by Aberystwyth University's Graduate School Doctoral Training Programme.

肝吸虫（肝片形吸虫）是一种高致病性吸虫寄生虫，在全球牛和羊中非常流行，其疾病、片吸虫病估计每年给欧洲牲畜生产者造成超过 20 亿英镑的损失。气候变化和驱虫药耐药性正在推动肝吸虫患病率的上升。在全球范围内，这种患病率的增加严重影响了动物的健康、福利和生产力，并威胁到某些地区畜牧业生产的可持续性。为了减轻这种威胁，并在未来几十年内可持续地控制肝吸虫，需要替代方案。这些替代策略可能针对肝镰刀菌的生命周期，该生命周期以中间蜗牛宿主（Galba truncatula）为中心，这种蜗牛仅存在于最佳环境和微气候条件允许其繁衍生息的牧场地区。包括轮牧、对危险区域进行临时或永久围栏以及对牲畜进行针对性处理等减少牧场肝镰刀菌卵污染的策略可能会阻碍其生命周期。障碍阻碍了这些替代控制策略的大规模采用。对农场中 G. truncatula 栖息地的空间分布了解不足，阻碍了农民成功应用针对蜗牛的措施的能力。关于如何优化这些替代策略的信息也很有限。近年来，该项目的监督团队开发了新颖的研究工具，使研究人员能够在以下地点调查 G. truncatula 和 F. hepatica 的流行病学：其中包括开发环境 DNA 检测，可以识别农田中是否存在 G. truncatula（Jones 等，2018），以及机械建模技术，可以准确地模拟农场水平上的 F. hepatica 感染风险。 Beltrame 等人，2018）。该项目旨在利用这些工具来开发和评估农场具体指南，以成功应用非化学控制方法来控制英国的肝镰刀菌。在博士课程期间，未来的学生将评估和比较一系列 DNA 提取方法和分子工具，以确定 G. truncatula eDNA 捕获、提取和扩增的最佳方法，然后将确定的最佳方法应用于 G. 农场。还将在这些采样点收集 truncatula 蜗牛栖息地的环境和气候测量结果，并结合 eDNA 调查结果进行分析，以确定与 truncatula 蜗牛存在相关的因素。最后，机械模型将评估放牧轮作、蒺藜蒺藜栖息地的临时和永久围栏以及有针对性的治疗措施的影响，以最大限度地减少吸虫卵对未来农场放牧牲畜感染肝片吸虫的风险。这些模型还将通过 eDNA 调查进行研究和绘制，评估应用这些策略的最佳时间范围、天气如何与农场地形和结构相互作用以影响其成功，以及牧场建筑如何。可以改变以增强基于放牧的控制对吸虫和共同感染线虫寄生虫的影响。未来的学生将获得分子生物学、寄生虫学、计算建模以及通用研究方法和交流方面的跨学科技能。将培养执行一系列 DNA 提取和扩增方法、从形态上识别中间蜗牛宿主和寄生虫生命阶段以及开发和应用机械模型的技能。培训将由监督团队和阿伯里斯特威斯大学研究生院博士培训计划。