How does ecological community influence livestock parasite transmission?

寄生虫和病媒传播疾病（VBD）是全球动物健康状况不佳和反刍动物生产力下降的主要原因，威胁着粮食安全和可持续畜牧业生产。潜在的影响包括商业牲畜饲养系统每英亩生产的肉或奶的重量减少，以及资源贫乏的生计小农场的小牧群完全消失。寄生虫丰度和VBD传播模型已被开发出来，可用于设计和改善兽医干预计划或放牧管理，以最大限度地减少疾病风险。然而，研究和模型开发主要集中在集约化管理的反刍动物畜牧系统，其中单一物种主要是草单一栽培。较少注意的是广泛的生产系统，其中感兴趣的牲畜宿主和寄生虫物种是更广泛的生态社区的一部分，例如英国的社区放牧和南部非洲的旱地畜牧系统。在这些物种多样性的环境中，推荐的减少寄生虫感染的干预措施的有效性是未知的。此外，虽然野生动物对世界各地的许多畜牧业农民来说是一种冲突，但最近的研究表明，共同放牧牲畜和野生动物可能是有益的，可以提高饲料质量，减少蜱虫数量，并从环境中清除胃肠道线虫幼虫。需要进一步研究，以制定寄生虫控制的干预战略，考虑到社区生态和人类-野生动物冲突缓解战略的潜在流行病学影响。学生将：1。在CASE合作伙伴非洲大象协会（EfA）的支持下，描述博茨瓦纳Makgadikgadi Pans国家公园（MPNP）及其周围的社区生态（包括哺乳动物宿主，寄生虫和植被）。EfA的纵向空间数据集的哺乳动物物种存在的MPNP将补充与学生自己的观察寄生虫的多样性在环境中，并在非侵入性收集的样本从哺乳动物宿主。将从文献和约34，000个宿主-蜱虫协会的开放数据库6中提取其他宿主-寄生虫协会，以构建群落结构和季节性共享栖息地使用的新型网络模型7.2。预测社区结构和干预措施对牲畜接触寄生虫的影响，进而预测牲畜感染寄生虫/病媒传播疾病的风险。在网络模型上进行的全球敏感性分析将确定候选的关键宿主物种和栖息地以及限制牲畜接触寄生虫的社区生态条件。将VBD传输3引入网络模型进一步允许预测潜在干预措施的预期功效。3.使用实地观察结果验证模型输出结果：将通过测量环境中的寄生虫丰度和牲畜感染强度，在实地检验模型输出结果和假设。在MPNP附近可以找到具有一系列社区结构的潜在实地地点。例如，一些养牛场排斥所有其他大型哺乳动物物种，采用密集的寄生虫控制战略，并通过焚烧来管理植被，私人禁猎区往往排斥大型食草动物，但允许反刍牲畜和野生动物共同放牧，在农村小农户村庄可以观察到不同程度的野生动物-牲畜同域现象。试点研究表明，在博茨瓦纳，野生动物与牲畜的相互作用很常见，反刍动物寄生虫负担很高，寄生虫对自给农民的粮食安全的影响很大。因此，寄生和社区生态可以很容易地观察和测量。学生将能够应用和完善通过DTP培训开发的技能，以开发和测试自己的假设，同时也产生一个新的假设。

Parasitic and vector-borne diseases (VBDs) are a major cause of poor animal health and reduced ruminant livestock productivity worldwide, threatening food security and sustainable livestock production. Potential impacts range from reduced weight of meat or milk produced per acreage in commercial livestock rearing systems, to the complete loss of small herds on resource-poor subsistence smallholdings. Parasite abundance and VBD transmission models have been developed that can be used to design and improve veterinary intervention programmes or grazing management to minimise disease risk. However, research and model development has largely focussed on intensively managed ruminant livestock systems, where single species are reared on primarily grass monoculture. Less attention has been given to extensive production systems where the livestock host and parasite species of interest are part of a wider ecological community e.g. communal grazing in the UK, and dryland pastoral systems in Southern Africa. In species-diverse environments such as these, the validity of recommended interventions to reduce parasitic infection is unknown. Furthermore, although wildlife present a conflict for many livestock farmers worldwide, recent studies suggest that co-grazing livestock and wildlife may be beneficial, improving forage quality, reducing tick abundance, and removing gastrointestinal nematode larvae from the environment. Further research is needed to develop intervention strategies for parasite control that take into account community ecology and the potential epidemiological impact of human-wildlife conflict mitigation strategies. The student will:1. Characterise community ecology (including mammalian hosts, parasites and vegetation) in and around the Makgadikgadi Pans National Park (MPNP), Botswana, with the support of the CASE partner, Elephants for Africa (EfA). EfA's longitudinal spatial datasets of mammal species presence in the MPNP will be supplemented with the student's own observations of parasite diversity in the environment and in samples collected non-invasively from mammalian hosts. Additional host-parasite associations will be extracted from the literature and an open database of ~34,000 host-tick associations6 to construct a novel network model of community structure and seasonal shared habitat use7.2. Predict the impact of community structure and intervention measures on livestock exposure to parasites and, by extension, parasitic/vector-borne disease risk in livestock. Global sensitivity analysis performed on the network model will identify candidate keystone host species and habitats and community ecology conditions which limit livestock exposure to parasites. Introducing VBD transmission3 to the network model further allows the expected efficacy of potential intervention measures to be predicted. 3. Validate model output using field observations.Model output and hypotheses developed will be tested in the field by measuring parasite abundance in the environment and intensity of infection in livestock. Potential field sites with a range of community structures can be found within easy reach of the MPNP. For example, some cattle ranches exclude all other large mammal species, apply intensive parasite control strategies and manage vegetation cover by burning, private game reserves often exclude megaherbivores but allow ruminant livestock and wildlife to co-graze, and a range of degrees of wildlife-livestock sympatry can be observed in rural smallholder villages. Pilot research suggests that in Botswana wildlife-livestock interactions are common, ruminant parasite burdens are high, and the consequences of parasitism for the food security of subsistence farmers are high. Thus parasitism and community ecology can be readily observed and measured. The student will be able to apply and refine skills developed through their DTP training to develop and test their own hypotheses, whilst also generating o