Collaborative Research (RAPID): Testing Intervention Strategies to Change the Outcome of Disease-caused Mass-mortality Events in a Declining Amphibian

新的疾病正在以越来越快的速度出现，在许多情况下，正在对野生动物物种造成毁灭性的影响。两栖壶菌病(Batrachochytrium endrobatidis；Bd)是一种两栖真菌病，自出现以来，已导致全世界数百种两栖动物的灭绝或严重衰退。在加利福尼亚州的内华达州S山脉，壶菌病已经导致曾经常见的山地黄腿青蛙濒临灭绝。在2012年夏季，现存最大数量的山地黄腿青蛙种群将因Bd最近抵达该地区而发生灭绝事件。在山地黄腿青蛙种群中，Bd进入以前未感染的种群通常会导致青蛙种群的灭绝，拟议研究的目标是将结果改变为青蛙种群的长期持续存在。这种疾病干预将采取在Bd引起的青蛙死亡期间进行的野外实验的形式。在这项实验中，将在整个青蛙种群的范围内评估两种治疗方法的有效性，(1)抗真菌药物，和(2)增强自然出现在青蛙皮肤上的抗真菌细菌。这项实验还将提供一个机会来描述治疗效果的潜在机制，包括青蛙免疫系统的作用，青蛙皮肤上存在的微生物群落，以及青蛙的快速进化。根据之前实验室和小规模田间试验的结果，预计抗真菌药物和细菌增强处理将提高青蛙的存活率，而不是不治疗的青蛙。拟议研究的结果将对针对世界各地受到新出现疾病威胁的野生动物物种(如两栖动物、蝙蝠、类人猿)的保护工作产生重要影响。这项研究还将为本科生和研究生提供培训机会，尽一切努力最大限度地将代表人数不足的群体包括在内。

New diseases are emerging at an increasing rate, and in numerous cases are having devastating effects on wildlife species. The amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd) causes the disease chytridiomycosis that since its emergence has resulted in the extinction or serious decline of hundreds of amphibian species worldwide. In California?s Sierra Nevada, chytridiomycosis has caused the near-extinction of the once-common mountain yellow-legged frog. During summer 2012, the largest remaining mountain yellow-legged frog population will suffer a die-off event caused by the recent arrival of Bd in the area. In mountain yellow-legged frog populations the arrival of Bd in a previously uninfected population typically results in frog population extinction, and the goal of the proposed study is to change the outcome to long-term frog population persistence. This disease intervention will take the form of a field experiment implemented during the Bd-caused frog die-off. In this experiment the effectiveness of two treatments, (1) an antifungal drug, and (2) the augmentation of antifungal bacteria that occur naturally on frog skin, will be assessed at the scale of an entire frog population. This experiment will also provide an opportunity to describe the mechanisms underlying treatment effectiveness, including the role of the frog immune system, the microbial community present on the skin of frogs, and rapid evolution in frogs. Based on results from previous laboratory and small-scale field trials it is expected that antifungal drug and bacterial augmentation treatments will increase frog survival relative to frogs that are left untreated. Results from the proposed study will have important implications for conservation efforts aimed at wildlife species worldwide that are threatened by emerging diseases (e.g., amphibians, bats, apes). The study will also provide training opportunities for undergraduate and graduate students, with every effort made to include those from underrepresented groups to the maximum extent possible.