Strain diversity and spatial distribution are linked to epidemic dynamics in host populations

The inherently variable nature of epidemics renders predictions of when and where infection is expected to occur challenging. Differences in pathogen strain composition, diversity, fitness, and spatial distribution are generally ignored in epidemiological modeling and are rarely studied in natural populations, yet they may be important drivers of epidemic trajectories. To examine how these factors are linked to epidemics in natural host populations, we collected epidemiological and genetic data from fifteen populations of the powdery mildew fungus, Podosphaera plantaginis, on Plantago lanceolata in the Åland Islands, Finland. In each population, we tracked spatiotemporal disease progression throughout one epidemic season and coupled our survey of infection with intensive field sampling of the pathogen. We found that strain composition varied greatly among populations in the landscape. Within populations, strain composition was driven by the sequence of strain activity: early-active stra...传染病本身固有的可变特性，使得预测感染发生的时间与地点极具挑战性。流行病学建模通常忽略病原菌株组成、多样性、适应性以及空间分布的差异，且此类差异在自然种群中极少被研究，但它们可能是传染病流行轨迹的重要驱动因素。为探究这些因素与自然宿主种群中传染病流行的关联，我们于芬兰奥兰群岛（Åland Islands）采集了长叶车前（Plantago lanceolata）上15个白粉菌（powdery mildew）真菌Podosphaera plantaginis种群的流行病学与遗传学数据。针对每个种群，我们在一整个流行季中追踪了病害的时空动态，并将感染调查与病原菌的高密度野外采样相结合。研究发现，景观中不同种群的菌株组成差异显著。在种群内部，菌株组成由菌株活性的时序所驱动：早活性菌株……