The fungal pathogen Batrachochytrium dendrobatidis (Bd) is implicated in global mass die-offs and declines in amphibians. In Mesoamerica, the Bd epidemic wave hypothesis is supported by detection of Bd in historic museum specimens collected over the last century, yet the timing and impact of the early stages of the wave remain poorly understood. Chiropterotriton magnipes, the only obligate troglodytic Neotropical salamander, was abundant in its small range in the decade following its description in 1965, but subsequently disappeared from known localities and was not seen for 34 years. Its decline is roughly coincident with that of other populations of Neotropical salamanders associated with the invasion and spread of Bd. To determine the presence and infection intensity of Bd on C. magnipes and sympatric amphibian species (which are also Bd hosts), we used a noninvasive sampling technique and qPCR assay to detect Bd on museum specimens of C. magnipes collected from 1952 to 2012, and from extant populations of C. magnipes and sympatric species of amphibians. We also tested for the presence of the recently discovered Batrachochytrium salamandivorans (Bsal), another fungal chytridiomycete pathogen of salamanders, using a similar technique specific for Bsal. We did not detect Bd in populations of C. magnipes before 1969, while Bd was detected at low to moderate prevalence just prior to and during declines. This pattern is consistent with Bd-caused epizootics followed by host declines and extirpations described in other hosts. We did not detect Bsal in any extant population of C. magnipes. We obtained one of the earliest positive records of the fungus to date in Latin America, providing additional historical evidence consistent with the Bd epidemic wave hypothesis. Genotyping results show that at least one population is currently infected with the Global Panzootic Lineage of Bd, but our genotyping of the historical positive samples was unsuccessful. The lack of large samples from some years and the difficulty in genotyping historical Bd samples illustrate some of the difficulties inherent in assigning causality to historical amphibian declines. These data also provide an important historical baseline for actions to preserve the few known remaining populations of C. magnipes.

中文翻译：

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唯一专性穴居新热带蝾螈的真菌感染、衰退和持续存在

真菌病原体 Batrachochytrium dendrobatidis (Bd) 与全球大规模死亡和两栖动物数量下降有关。在中美洲，Bd 流行波假说得到了在上个世纪收集的历史博物馆标本中检测到 Bd 的支持，但对该波早期阶段的时间和影响仍然知之甚少。Chiropterotriton magnipes 是唯一的专性穴居新热带蝾螈，在 1965 年被描述后的十年间在其小范围内大量存在，但随后从已知地点消失，34 年未见。它的下降与与 Bd 的入侵和传播相关的其他新热带蝾螈种群的下降大致一致。为了确定 Bd 在 C. magnipes 和同域两栖动物物种（也是 Bd 宿主）上的存在和感染强度，我们使用非侵入性采样技术和 qPCR 分析检测了 1952 年至 2012 年收集的 C. magnipes 博物馆标本以及现存的 C. magnipes 种群和两栖动物同域物种中的 Bd。我们还使用专门针对 Bsal 的类似技术测试了最近发现的 Batrachochytrium salamandivorans (Bsal) 的存在，这是另一种蝾螈的真菌壶菌病原体。我们在 1969 年之前没有在 C. magnipes 种群中检测到 Bd，而在下降之前和下降期间检测到 Bd 的流行率是低到中等。这种模式与 Bd 引起的流行病一致，随后是其他宿主中描述的宿主下降和灭绝。我们没有在任何现存的 C. magnipes 种群中检测到 Bsal。我们获得了迄今为止拉丁美洲最早的真菌阳性记录之一，提供与 Bd 流行波假说一致的额外历史证据。基因分型结果表明，目前至少有一个种群感染了 Bd 的全球泛动物谱系，但我们对历史阳性样本的基因分型没有成功。一些年份缺乏大样本以及对历史 Bd 样本进行基因分型的困难说明了将因果关系归因于历史两栖动物减少的一些固有困难。这些数据还为采取行动保护少数已知的 C. magnipes 剩余种群提供了重要的历史基线。但是我们对历史阳性样本的基因分型没有成功。一些年份缺乏大样本以及对历史 Bd 样本进行基因分型的困难说明了将因果关系归因于历史两栖动物减少的一些固有困难。这些数据还为采取行动保护少数已知的 C. magnipes 剩余种群提供了重要的历史基线。但是我们对历史阳性样本的基因分型没有成功。一些年份缺乏大样本以及对历史 Bd 样本进行基因分型的困难说明了将因果关系归因于历史两栖动物减少的一些固有困难。这些数据还为采取行动保护少数已知的 C. magnipes 剩余种群提供了重要的历史基线。