Emerging infectious diseases rank among the most important threats to human and wildlife health. A comprehensive understanding of the mode of infection and presence of potential reservoirs is critical for the development of effective counter strategies. Fungal pathogens can remain viable in environmental reservoirs for extended periods of time before infecting susceptible individuals. This may be the case for Pseudogymnoascus destructans (Pd), the causative agent of bat white-nose disease. Owing to its cold-loving nature, this fungal pathogen only grows on bats during hibernation, when their body temperature is reduced. Bats only spend part of their life cycle in hibernation and do not typically show signs of infection in summer, raising the question of whether Pd remains viable in hibernacula during this period (roughly six months). If so, this could facilitate the re-infection of bats when they return to the sites the following winter. In a laboratory experiment, we determined the germination rate of Pd spores kept under constant conditions on a wall-like substrate, over the course of two years. Results showed that the seasonal pattern in Pd germination mirrored the life cycle of the bats, with an increased germination rate at times when hibernating bats would naturally be present and lower germination rates during their absence. We suggest that Pd is dependent on the presence of hibernating bats and has therefore coupled its germination rate to host availability. Furthermore, we demonstrate that Pd spores survive extended periods of host absence and can remain viable for at least two years. There is, however, a strong decrease in spore viability between the first and second years (98%). Pd viability for at least two years on a solid mineral-based substrate establishes the potential for environmental reservoirs in hibernacula walls and has strong implications for the efficacy of certain management strategies (e.g. bat culling).

中文翻译：

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变形假单胞菌萌发的季节性模式表明宿主-病原体协同进化。

新兴传染病是对人类和野生生物健康的最重要威胁。对感染模式和潜在水库的存在的全面了解对于制定有效的应对策略至关重要。在感染易感个体之前，真菌病原体可以在环境水库中长期存活。蝙蝠白鼻病的病原体Pseudogymnoascus destructans（Pd）可能就是这种情况。由于其嗜冷性，这种真菌病原体仅在蝙蝠冬眠时体温降低时才生长。蝙蝠仅在冬眠中度过其生命周期的一部分，通常在夏季没有感染的迹象，这引发了一个问题，即在此期间（大约六个月），Pd在冬虫夏草中是否仍能存活。如果是这样，当蝙蝠在第二个冬天回到家中时，这可以促进蝙蝠的再次感染。在实验室实验中，我们确定了在两年的过程中，在恒定条件下保持在壁状基质上的Pd孢子的发芽率。结果表明，Pd萌发的季节性模式反映了蝙蝠的生命周期，有时会自然出现冬眠的蝙蝠，发芽率会增加，而在没有蝙蝠的情况下发芽率会降低。我们建议Pd依赖于冬眠蝙蝠的存在，因此已将其发芽率与宿主的可用性联系在一起。此外，我们证明Pd孢子可以在宿主缺席的情况下存活很长时间，并且可以保持至少两年的生存期。但是，有 第一年和第二年之间（98％）的孢子生存力大幅下降。在固体矿物基基质上，Pd的生存能力至少要两年，才能为冬眠壁上的环境储集层建立潜力，并对某些管理策略（例如蝙蝠剔除）的效力产生重大影响。