Dissertation Research: Evolution of Virulence in Sterilizing Pathogens: Spatial Models and Field Studies

人们通常认为，病原体会朝着无害的方向进化，这样就不会导致宿主种群的灭绝，从而也不会导致病原体自身的灭绝。这一观点一直存在争议，理由是选择降低毒力需要整个种群的差异灭绝，这一过程被认为是缓慢而无效的。这项研究将使用理论模型来调查在宿主和病原体分布在一个大的空间区域，但它们的传播更局部的情况下，是否会发生毒性降低的进化。模型假设将用白营的花药黑穗病进行检验。这是一种被充分研究的疾病，它能部分地使宿主绝育。鉴于目前对新出现的传染病的关注，理解为什么有些病原体会引起非常严重的疾病症状，而另一些病原体对其宿主的影响很小是很重要的。由于病原体的进化，疾病症状可以随着时间的推移而改变，但这种变化的预测方向和机制一直很有争议。这项研究将模拟所涉及的过程，因此有助于预测传染病严重程度未来可能的变化方向。

Antonovics9976250It is commonly suggested that pathogens will evolve toward being harmless so as not to cause the extinction of the host population and hence of themselves. This idea has been disputed on the grounds that selection for reduced virulence would require differential extinction of whole populations, a process that has been considered to be slow and ineffective. This study will use theoretical models to investigate whether the evolution of reduced virulence can occur in situations where the host and pathogen are distributed over a large spatial area, but where their dispersal is much more local. Model assumptions will be tested using the anther-smut disease of white campion. This is as a well-studied disease that partly sterilizes its host. Given present day concerns about emerging infectious diseases, it is important to understand why some pathogens cause very severe disease symptoms, yet others have only a small effect on their hosts. Disease symptoms can change over time as a result of pathogen evolution, but the predicted direction and mechanism of such change has been very controversial. This study will model the processes involved, and therefore help predict possible future directions of change in the severity of infectious diseases.