Host-parasite population dynamics in experimental arenas

我的长期研究目标是确定影响宿主-寄生虫种群动态的因素，以预测控制干预措施的后果。 了解寄生生物如何影响其宿主种群的挑战之一是，研究要么是在实地进行的（许多因素影响结果），要么是在严格控制的实验室实验中进行的（条件与真实的世界相去甚远）。 为了克服这一点，我使用了两个实验系统，其中寄生虫和宿主在半自然环境中相互作用：（1）一种寄生在孔雀鱼皮肤和鳍上的体外寄生虫，当鱼相互接触时，以及（2）一种线虫寄生虫，生活在老鼠的肠内，在粪便中释放卵，卵孵化成幼虫，然后被其他动物摄取人口中的老鼠。 这一建议涉及三个问题。 (1)我们将通过生活在不同浓度的水性锌的孔雀鱼种群，比较体外寄生虫的流行传播模式。 锌是一种常见的污染物，特别是在水产养殖场周围，我们的研究结果将表明锌的存在是否可能增加疾病爆发的频率。 (2)我们的第二组实验将用于解释为什么遗传上对线虫寄生虫易感的小鼠品系在传播率较低时对感染更具抵抗力，但遗传抗性小鼠不会变得更具抵抗力。 在动物和人类群体中，控制计划试图降低传播率，如果我们更好地了解传播率和感染抵抗力之间的联系，这些计划的设计将受益。 (3)最后，我们将试图了解当小鼠的能量资源有限时，哪些生物过程优先。 我们将测量小鼠在营养不良和感染线虫寄生虫时的生长、繁殖和维持功能性免疫反应的情况。 随着人类活动的不断扩大，野生动物的压力越来越大。 我们的工作，以了解他们如何处理竞争的需求可能会指导生物学家，因为他们试图更好地管理野生动物种群。

My long-term research objective is to identify factors that affect host-parasite population dynamics in order to anticipate the consequences of control interventions. One of the challenges of understanding how parasitic organisms affect their host population is that research is done either in the field (where many factors influence the results) or in tightly controlled laboratory experiments (where conditions are far from those of the real world). To overcome this, I use 2 experimental systems where the parasite and host interact together in a semi-natural setting: (1) an ectoparasite that lives on the skin and fin of guppies and spreads through the population when fish come in contact with each other, and (2) a nematode parasite that lives in the intestine of mice and releases eggs in the faeces that hatch into larval stages that are then ingested by other mice in the population. This proposal addresses 3 questions. (1) We will compare the pattern of epidemic spread of the ectoparasite through guppy populations that are living in different concentrations of waterborne zinc. Zinc is a common pollutant, especially around aquaculture sites, and our results will indicate whether the presence of zinc is likely to increase the frequency of disease outbreaks. (2) Our second set of experiments will be used to explain why strains of mice that are genetically susceptible to the nematode parasite become more resistant to infection if the transmission rates are low, but that the genetically resistant mice don't become more resistant. In animal and human populations, control programs attempt to reduce rates of transmission, and design of these programs will benefit if we better understand the link between transmission rate and resistance to infection. (3) Finally, we will attempt to understand which biological processes take precedence when mice have limited energetic resources. We will measure how well mice grow, reproduce and maintain a functional immune response when they are malnourished and also infected with a nematode parasite. With ever expanding human activities, wild animals are increasingly stressed. Our work to understand how they handle competing demands may guide biologists as they try to better manage wild animal populations.