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，在许多情况下对野生动物物种产生毁灭性影响。两栖类壶菌（Batrachochytrium dendrobatium; Bd）引起壶菌病，自其出现以来，已导致全世界数百种两栖类物种灭绝或严重衰退。在加州？在美国内华达州的塞拉山脉，壶菌病已经导致曾经很常见的山地黄腿蛙濒临灭绝。在2012年夏天，最大的剩余山黄腿蛙种群将遭受死亡事件所造成的最近抵达该地区的Bd。在山地黄腿蛙种群中，Bd在以前未感染的种群中的到来通常会导致青蛙种群灭绝，拟议研究的目标是将结果改变为长期青蛙种群持续性。这种疾病干预将采取在BD引起的青蛙死亡期间实施的田间实验的形式。在本实验中，将在整个青蛙种群的规模上评估两种治疗方法的有效性，（1）抗真菌药物，和（2）增加青蛙皮肤上天然存在的抗真菌细菌。该实验还将提供一个机会来描述治疗有效性的机制，包括青蛙免疫系统的作用，青蛙皮肤上的微生物群落以及青蛙的快速进化。根据以前的实验室和小规模田间试验的结果，预计抗真菌药物和细菌强化治疗将增加青蛙相对于未经治疗的青蛙的存活率。拟议研究的结果将对针对全球受新兴疾病威胁的野生动物物种的保护工作产生重要影响（例如，两栖动物、蝙蝠、猿）。这项研究还将为本科生和研究生提供培训机会，并尽一切努力最大限度地包括代表性不足群体的学生。

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.