Institute of Vertebrate Biology, Czech Academy of Sciences, Květná 8, 603 65 Brno, Czech Republic; Institute of Biostatistics and Analyses, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic.
Institute of Automation and Computer Science, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno, Czech Republic.
J Theor Biol. 2019 Mar 7;464:98-103. doi: 10.1016/j.jtbi.2018.12.026. Epub 2018 Dec 20.
Where microbes colonizing skin surface may help maintain organism homeostasis, those that invade living skin layers cause disease. In bats, white-nose syndrome is a fungal skin infection that affects animals during hibernation and may lead to mortality in severe cases. Here, we inferred the amount of fungus that had invaded skin tissue of diseased animals. We used simulations to estimate the unobserved disease severity in a non-lethal wing punch biopsy and to relate the simulated pathology to the measured fungal load in paired biopsies. We found that a single white-nose syndrome skin lesion packed with spores and hyphae of the causative agent, Pseudogymnoascus destructans, contains 48.93 pg of the pathogen DNA, which amounts to about 1560 P destructans genomes in one skin lesion. Relating the information to the known UV fluorescence in Nearctic and Palearctic bats shows that Nearctic bats carry about 1.7 µg of fungal DNA per cm, whereas Palearctic bats have 0.04 µg cm of P. destructans DNA. With the information on the fungal load that had invaded the host skin, the researchers can now calculate disease severity as a function of invasive fungal growth using non-destructive UV light transillumination of each bat's wing membranes. Our results will enable and promote thorough disease severity assessment in protected bat species without the need for extensive animal and laboratory labor sacrifices.
当定植于皮肤表面的微生物有助于维持机体的内稳态时，那些侵入皮肤活层的微生物则会引发疾病。在蝙蝠中，白鼻综合征是一种真菌性皮肤感染，会在冬眠期间影响动物，并在严重情况下导致死亡。在这里，我们推断了感染患病动物皮肤组织的真菌数量。我们使用模拟来估计非致死性翅膀打孔活检中未观察到的疾病严重程度，并将模拟的病理学与配对活检中测量的真菌负荷相关联。我们发现，一个充满致病真菌——假丝酵母菌（Pseudogymnoascus destructans）的孢子和菌丝的单一白鼻综合征皮肤病变，含有 48.93 pg 的病原体 DNA，这相当于一个皮肤病变中有大约 1560 个 P. destructans 基因组。将这一信息与已知的北美和欧亚蝙蝠的近紫外荧光相关联表明，北美蝙蝠每平方厘米携带约 1.7 µg 的真菌 DNA，而欧亚蝙蝠的 P. destructans DNA 为每平方厘米 0.04 µg。有了侵入宿主皮肤的真菌负荷信息，研究人员现在可以使用每个蝙蝠翅膀的非破坏性紫外光透射，根据侵入性真菌的生长来计算疾病的严重程度。我们的研究结果将能够促进对受保护蝙蝠物种的彻底疾病严重程度评估，而无需大量牺牲动物和实验室劳动。
