Data from: Host and pathogen ecology drive the seasonal dynamics of a fungal disease, white-nose syndrome

Seasonal patterns in pathogen transmission can influence the impact of disease on populations and the speed of spatial spread. Increases in host contact rates or births drive seasonal epidemics in some systems, but other factors may occasionally override these influences. White-nose syndrome, caused by the emerging fungal pathogen Pseudogymnoascus destructans, is spreading across North America and threatens several bat species with extinction. We examined patterns and drivers of seasonal transmission of P. destructans by measuring infection prevalence and pathogen loads in six bat species at 30 sites across the eastern United States. Bats became transiently infected in autumn, and transmission spiked in early winter when bats began hibernating. Nearly all bats in six species became infected by late winter when infection intensity peaked. In summer, despite high contact rates and a birth pulse, most bats cleared infections and prevalence dropped to zero. These data suggest the dominant driver of seasonal transmission dynamics was a change in host physiology, specifically hibernation. Our study is the first, to the best of our knowledge, to describe the seasonality of transmission in this emerging wildlife disease. The timing of infection and fungal growth resulted in maximal population impacts, but only moderate rates of spatial spread.

病原体传播的季节性模式可影响疾病对种群的冲击强度与空间传播速度。在部分生态系统中，宿主接触率升高或种群出生高峰会驱动季节性流行病的发生，但其他因素有时可抵消这类影响。由新兴真菌病原体破坏性假裸囊菌（Pseudogymnoascus destructans）引发的白鼻综合征（White-nose syndrome）正在北美地区扩散，对多个蝙蝠物种构成灭绝威胁。我们在美国东部30个采样点，对6种蝙蝠的感染率（infection prevalence）与病原体载量（pathogen loads）进行检测，以此分析破坏性假裸囊菌季节性传播的模式与驱动因素。蝙蝠在秋季出现一过性感染，而当蝙蝠开始进入冬眠的初冬时节，传播出现激增。至晚冬感染强度达到峰值时，6个蝙蝠物种的几乎所有个体均已被感染。尽管夏季宿主接触率较高且存在出生高峰，但多数蝙蝠可清除体内感染，感染率降至零。上述数据表明，季节性传播动态的主导驱动因素为宿主生理状态的改变，具体即冬眠行为。据我们所知，本研究首次阐明了这一新兴野生动物传染病的传播季节性特征。感染与真菌增殖的时机使得种群受到了最大程度的负面影响，但空间传播速率仅处于中等水平。