Variability in environmental persistence but not per capita transmission rates of the amphibian chytrid fungus leads to differences in host infection prevalence
Variability in environmental persistence but not per capita transmission rates of the amphibian chytrid fungus leads to differences in host infection prevalence
复制标题
环境持久性的变化而非两栖壶菌的人均传播率导致宿主感染流行率的差异
DOI：
10.1111/1365-2656.13612
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发表时间：
2021
影响因子：
4.8
通讯作者：
Civitello, David J.
中科院分区：
文献类型：
--
作者：
Rumschlag, Samantha L.;Roth, Sadie A.;McMahon, Taegan A.;Rohr, Jason R.;Civitello, David J.
宿主群体之间感染的异质性可能通过两种机制因环境条件的差异而产生。首先，环境条件可能通过影响生存来改变宿主对病原体的暴露。第二，环境条件可能改变宿主的易感性，如果宿主和病原体之间发生接触，感染的可能性或多或少。此外，宿主的易感性可能会通过获得性抗性而改变，在某些系统中，宿主可以通过接触死亡或腐烂的病原体及其代谢物而产生获得性抗性。环境条件可能会改变病原体的分解率，影响宿主发展获得性resistance.The本研究主要测试环境背景如何影响相对贡献的病原体生存和人均传播宿主感染流行率使用两栖壶菌（Batrachochytrium dendrobaerum; Bd）作为一个模型系统。其次，我们评估了环境背景如何影响Bd的分解，因为以前的研究表明，死亡的Bd及其代谢产物可以在宿主中非法获得抗性。我们进行了Bd存活和感染实验，然后拟合模型，以了解Bd死亡率、分解率和人均传播率在水源（例如人工泉水（ASW）或三个池塘的水）之间的变化。我们发现，感染率在水源之间存在差异，这是由Bd死亡率的差异驱动的，而不是人均传播率的差异。Bd的死亡率各不相同，池塘水处理，并在ASW较低pond water.These结果表明，在Bd感染动态的变化可能是一个功能的环境因素，在水体中，导致暴露的主机活Bd的差异。与活菌Bd的持久性相反，我们发现死菌Bd的分解速率在水源之间没有变化，这可能表明宿主暴露于死菌Bd或其代谢产物在附近的站点之间可能不存在差异。最终，对自由生活的病原体的环境依赖性的机械理解可以导致对暴发异质性模式的更深入理解，这可以为监测和管理策略提供信息。
Heterogeneities in infections among host populations may arise through differences in environmental conditions through two mechanisms. First, environmental conditions may alter host exposure to pathogens via effects on survival. Second, environmental conditions may alter host susceptibility, making infection more or less likely if contact between a host and pathogen occurs. Further, host susceptibility might be altered through acquired resistance, which hosts can develop, in some systems, through exposure to dead or decaying pathogens and their metabolites. Environmental conditions may alter the rates of pathogen decomposition, influencing the likelihood of hosts developing acquired resistance.The present study primarily tests how environmental context influences the relative contributions of pathogen survival and per capita transmission on host infection prevalence using the amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd) as a model system. Secondarily, we evaluate how environmental context influences the decomposition of Bd because previous studies have shown that dead Bd and its metabolites can illicit acquired resistance in hosts. We conducted Bd survival and infection experiments and then fit models to discern how Bd mortality, decomposition and per capita transmission rates vary among water sources [e.g. artificial spring water (ASW) or water from three ponds].We found that infection prevalence differed among water sources, which was driven by differences in mortality rates of Bd, rather than differences in per capita transmission rates. Bd mortality rates varied among pond water treatments and were lower in ASW compared to pond water.These results suggest that variation in Bd infection dynamics could be a function of environmental factors in waterbodies that result in differences in exposure of hosts to live Bd. In contrast to the persistence of live Bd, we found that the rates of decomposition of dead Bd did not vary among water sources, which may suggest that exposure of hosts to dead Bd or its metabolites might not commonly vary among nearby sites. Ultimately, a mechanistic understanding of the environmental dependence of free‐living pathogens could lead to a deeper understanding of the patterns of outbreak heterogeneity, which could inform surveillance and management strategies.