Local adaptations to infectious diseases: curse or opportunity?

传染病在世界范围内流行于人类和野生动物。然而，毒力、流行率、耐受性和耐药性的模式并不独特，通常依赖于环境，并且使关于传播和潜在缓解的预测成为挑战。我的研究计划的长期目标是评估在广泛的地理范围内与疾病相关的性状的变化，并揭示复杂的传染病及其在当地预防的作用，我们的理解的多种因素。在这种情况下，两栖动物是一个理想的模型，因为它们分布广泛，越来越多的证据表明，它们正面临全球性的下降，所有两栖动物物种中近10%的种群接近灭绝，另有32%被列为受威胁。此外，它们代表了一个非常好的研究系统，以调查生态和进化过程之间的联系，以及对调节宿主-寄生虫共同进化结果的机制的理解。在北美，林蛙，林蛙sylvatica，和北方豹蛙，蛙pipiens，是受病毒（Ranavirus）和壶菌（Batrachochytrium dendrobatium）影响的广泛分布的物种，我将调查这些病原体在整个宿主地理范围内的反应，使用现有的网络，从这两个宿主物种跨越从田纳西州到西北地区的纬度梯度。 结合实地和实验室的观察和实验，并考虑到宿主-寄生虫进化生态学的现有知识，我将通过以下问题解决这个五年资助周期的短期目标： 1.环境异质性如何调节宿主-病原体相互作用，以及这如何影响青蛙种群动态？ 2.宿主表型的变化是否与感染水平相关，以及这如何反映了对病原体的局部适应？ 3.病原体基因型的变异如何塑造青蛙种群的局部适应性？ 宿主是否已经并将继续适应这些快速进化的病原体，或者受到与环境整体变化（包括流行病）相关的相当大的威胁，仍然是进化生态学中的一个重要问题。最终，这项研究的结果将有助于实现我的长期目标，即建立一个理论和经验框架，以更好地了解野生动物中的传染病，并为野生动物保护提供流行病学工具。

Infectious diseases are prevalent worldwide in humans and wildlife. Yet, patterns of virulence, prevalence, tolerance, and resistance are not unique, often environment-dependent and make both predictions regarding spread and potential mitigations a challenge. The long-term goal of my Research Program is to assess variation in disease-related traits across a wide geographic range and uncover the multiple factors that complicate our understanding of infectious diseases and their role in local extinctions. In this context, Amphibians are an ideal model as they are widely distributed and increasing evidence suggests that they are facing global declines with nearly 10% of the populations of all amphibian species close to extinction and a further 32% classified as threatened. Additionally, they represent a very good study system to investigate questions around the links between ecological and evolutionary processes and the understanding of mechanisms that modulate host-parasite coevolutionary outcomes. In North-America, the Wood frog, Rana sylvatica, and the Northern Leopard frog, Rana pipiens, are widespread species affected by a virus (Ranavirus) and a chytrid fungus (Batrachochytrium dendrobatidis) and I will investigate the responses to these pathogens across the host geographic ranges, using an existing network of populations from these two host species across a latitudinal gradient spanning from Tennessee to the Northwest-Territories. Using a combination of field and lab-based observations and experiments and considering the current knowledge on host-parasite evolutionary ecology, my short-term objectives for this five year grant cycle will be addressed through the following questions: 1. How does environmental heterogeneity modulate the host-pathogen interactions, and how this may affect frog population dynamics? 2. Is variation in the host phenotype associated with infection levels and how this may reflect local adaptation to pathogens? 3. How does the variation in pathogen genotype shape local adaptation of frog populations? Whether hosts have been and will continue to adapt to these fast-evolving pathogens, or be under the considerable threat associated with an overall change in their environment, including pandemics remains an important question in evolutionary ecology. Ultimately, the results from this research will help reaching my long-term objectives to develop a theoretical and empirical framework for a better understanding of infectious diseases in wildlife as well as provide epidemiological tools for the conservation of wildlife.