Host resistance and tolerance to parasitism: importance of behaviour and habitat in a changing world

新出现和再出现的传染病是人类、家畜和野生动物健康的一个主要问题。有效的疾病管理需要深入了解宿主如何抵抗和容忍寄生，包括这些能力如何受到环境的影响。鉴于目前和预计的世界范围的环境变化，必须研究寄主栖息地和寄生之间的联系，而开发更好的预测工具的一个重要步骤是确定潜在的机制。使用两栖动物和它们的蠕虫寄生虫作为模型系统，我的实验室将使用一套新的跨学科工具和合作，通过三个特定的相关主题来机械地研究宿主的抗性和耐受性，这些主题将宿主、寄生虫和它们的环境之间的相互作用联系起来：1)宿主行为的作用，2)栖息地复杂性的影响，3)多种应激源的影响。行为防御可能发挥重要作用，因为简单地避免感染的成本应该更低，而且宿主也可以通过行为手段减轻感染的影响。通过研究作为抵抗和容忍寄生手段的行为，这项工作将提高我们对宿主防御的总体理解。宿主感染不仅取决于它们对病原体的反应，还取决于它们暴露于感染阶段的频率。我们的第二个主题将有助于预测栖息地改变如何影响疾病模式，通过考虑场地内条件如何影响宿主暴露。现在人们普遍认识到，多重压力源可以以意想不到的方式影响生物体，因此单独的检查不能准确反映大多数自然过程，并可能产生误导性的结论。然而，很少有研究将寄生虫感染与其他因素一起考虑为应激源。因此，我们的第三个主题将有助于更全面地了解寄生的代价和影响。由于两栖动物是世界上最危险的脊椎动物群体，疾病导致了它们的数量下降，我们的研究结果将产生关于宿主对寄生的抗性和耐受性驱动因素的新发现，有助于制定保护和管理策略，从而更好地了解野生动物疾病。对两栖动物寄生的研究也将产生适用于其他具有保护、文化和经济重要性的淡水生物的发现。

Emerging and re-emerging infectious diseases are a major concern for the health of humans, domestic animals, and wildlife. Effective disease management requires an intimate understanding of how hosts resist and tolerate parasitism, including how these abilities are affected by their environment. Given current and projected world-wide environmental changes, it is imperative to examine links between host habitat and parasitism and an essential next step for the development of better predictive tools is to identify underlying mechanisms. Using amphibians and their helminth parasites as a model system, my laboratory will use a suite of novel interdisciplinary tools and collaborations to mechanistically study host resistance and tolerance through three specific related themes that link interactions among hosts, parasites, and their environment: 1) the role of host behaviour, 2) the influence of habitat complexity, and 3) the impacts of multiple stressors. Behavioural defences may play a major role as it should be less costly to simply avoid infections, and hosts can also mitigate the impacts of infection through behavioural means. By investigating behaviour as a means to resist and tolerate parasitism, this work will improve our general understanding of host defences. Host infections are not just determined by their response to pathogens, but also by their frequency of exposure to infectious stages. Our second theme will help in predicting how habitat alterations influence disease patterns by considering how within-site conditions affect host exposure. It is now widely recognized that multiple stressors can affect organisms in unexpected ways, thus separate examinations do not accurately reflect most natural processes and can generate misleading conclusions. However, few studies have considered parasite infection as a stressor in conjunction with others. Consequently, our third theme will contribute to a more comprehensive view regarding the costs and implications of parasitism. Because amphibians are the most imperiled group of vertebrates worldwide, with diseases contributing to their decline, our results will produce novel findings regarding drivers of host resistance and tolerance to parasitism that aid in formulating conservation and management strategies to contribute towards a better understanding of wildlife diseases as a whole. The study of amphibian parasitism will also generate findings applicable to other freshwater organisms of conservation, cultural, and economic importance.