Department of Biological Sciences, Purdue University-Fort Wayne, Fort Wayne, Indiana, United States of America.
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America.
PLoS One. 2024 Oct 22;19(10):e0310954. doi: 10.1371/journal.pone.0310954. eCollection 2024.
Emerging pathogenic fungi have become a topic of conservation concern due to declines observed in several host taxa. One emerging fungal pathogen, Ophidiomyces ophidiicola, is well documented as the causative agent of ophidiomycosis, otherwise known as snake fungal disease (SFD). O. ophidiicola has been found to cause disease in a variety of snake species across the United States, including the eastern massasauga (Sistrurus catenatus), a federally threatened rattlesnake species. Most work to date has involved detecting O. ophidiicola for diagnosis of infection through direct sampling of snakes, and attempts to detect O. ophidiicola in the abiotic environment to better understand its distribution, seasonality, and habitat associations are lacking. We collected topsoil and groundwater samples from four macrohabitat types across multiple seasons in northern Michigan at a site where Ophidiomyces infection has been confirmed in eastern massasauga. Using a quantitative PCR (qPCR) assay developed for O. ophidiicola, we detected Ophidiomyces DNA in topsoil but observed minimal to no detection in groundwater samples. Detection frequency did not differ between habitats, but samples grouped seasonally showed higher detection during mid-summer. We found no relationships of detection with hypothesized environmental correlates such as soil pH, temperature, or moisture content. Furthermore, the distribution of Ophidiomyces positive samples across the site was not linked to estimated space use of massasaugas. Our data suggests that season has some effect on the presence of Ophidiomyces. Differences in presence between habitats may exist but are likely more dependent on the time of sampling and currently uninvestigated soil or biotic parameters. These findings build on our understanding of Ophidiomyces ecology and epidemiology to help inform where and when snakes may be exposed to the fungus in the environment.
新兴的致病性真菌已成为保护关注的话题，因为在几个宿主分类群中观察到了衰退。一种新兴的真菌病原体，蛇眼病霉（Ophidiomyces ophidiicola），被充分记录为蛇眼病（ophidiomycosis）的病原体，也称为蛇真菌病（SFD）。已经发现 O. ophidiicola 会导致美国各种蛇类患病，包括东部马萨诸塞响尾蛇（Sistrurus catenatus），这是一种受联邦威胁的响尾蛇物种。迄今为止，大多数工作都涉及通过直接对蛇进行采样来检测 O. ophidiicola 以诊断感染，并且缺乏在非生物环境中检测 O. ophidiicola 以更好地了解其分布、季节性和栖息地关联的尝试。我们在密歇根州北部的一个地点收集了来自四个宏观生境类型的表土和地下水样本，该地点已经确认了东部马萨诸塞响尾蛇感染了 Ophidiomyces。使用为 O. ophidiicola 开发的定量 PCR（qPCR）检测方法，我们在表土中检测到了 Ophidiomyces DNA，但在地下水样本中检测到的数量很少。栖息地之间的检测频率没有差异，但按季节分组的样本在仲夏期间检测到的频率更高。我们没有发现检测与假设的环境相关因素（如土壤 pH 值、温度或水分含量）之间的关系。此外，Ophidiomyces 阳性样本在整个地点的分布与估计的响尾蛇空间利用无关。我们的数据表明，季节对 Ophidiomyces 的存在有一定影响。栖息地之间存在差异的可能性，但可能更依赖于采样时间和当前未调查的土壤或生物参数。这些发现为我们对 Ophidiomyces 生态学和流行病学的理解提供了依据，以帮助了解蛇在环境中何时何地可能接触到真菌。
