Pseudogymnoascus destructans (Pd), the causative agent of white-nose syndrome in North America, has decimated bat populations within a decade. The fungus impacts bats during hibernation when physiological functions, including immune responses, are down-regulated. Studies have shown that Pd is native to Europe, where it is not associated with mass mortalities. Moreover, genomic and proteomic studies indicated that European bats may have evolved an effective immune defence, which is lacking in North American bats. However, it is still unclear which defence strategy enables European bats to cope with the pathogen. Here, we analyzed selected physiological and immunological parameters in torpid, Pd infected European greater mouse-eared bats (Myotis myotis) showing three different levels of infection (asymptomatic, mild and severe symptoms). From a subset of the studied bats we tracked skin temperatures during one month of hibernation. Contrasting North American bats, arousal patterns remained unaffected by Pd infections in M. myotis. In general, heavier M. myotis aroused more often from hibernation and showed less severe disease symptoms than lean individuals; most likely because heavy bats were capable of reducing the Pd load more effectively than lean individuals. In the blood of severely infected bats, we found higher gene expression levels of an inflammatory cytokine (IL-1β), but lower levels of an acute phase protein (haptoglobin), reactive oxygen metabolites (ROMs) and plasma non-enzymatic antioxidant capacity (OXY) compared to conspecifics with lower levels of infection. We conclude that M. myotis, and possibly also other European bat species, tolerate Pd infections during torpor by using selected acute phase response parameters at baseline levels, yet without arousing from torpor and without synthesizing additional immune molecules.

Pseudogymnoascus destructans (Pd)是北美白鼻综合征的病原体，在十年内使蝙蝠种群数量大幅减少。当包括免疫反应在内的生理功能被下调时，真菌会在冬眠期间影响蝙蝠。研究表明，钯原产于欧洲，与大规模死亡无关。此外，基因组和蛋白质组学研究表明，欧洲蝙蝠可能已经进化出一种有效的免疫防御，而北美蝙蝠则缺乏这种防御能力。然而，目前尚不清楚哪种防御策略能够让欧洲蝙蝠应对病原体。在这里，我们分析了迟钝的Pd感染的欧洲大鼠耳蝙蝠（Myotis myotis) 显示三种不同程度的感染（无症状、轻度和重度症状）。从研究的蝙蝠的一个子集中，我们跟踪了冬眠一个月的皮肤温度。与北美蝙蝠相比，M. myotis中的Pd感染对唤醒模式仍然没有影响。一般来说，较重的肌支原体更容易从冬眠中醒来，并且表现出的疾病症状比瘦弱的个体要轻；很可能是因为重型蝙蝠能够减少Pd比瘦人更有效地加载。在严重感染蝙蝠的血液中，我们发现炎症细胞因子 (IL-1β) 的基因表达水平较高，但急性期蛋白 (触珠蛋白)、活性氧代谢物 (ROM) 和血浆非酶抗氧化能力的水平较低。 OXY) 与感染水平较低的同种动物相比。我们得出结论，M. myotis以及可能还有其他欧洲蝙蝠物种，通过在基线水平使用选定的急性期反应参数，在麻木期间耐受Pd感染，但不会引起麻木，也不会合成额外的免疫分子。