Amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), has been recognized as the infectious disease causing the most catastrophic loss of biodiversity known to science, with South America being the most impacted region. We tested whether Bd prevalence is distributed among host taxonomy, ecoregion, conservation status and habitat preference in South America. Here we provide a synthesis on the extent of Bd infection across South America based on 21 648 molecular diagnostic assays, roles of certain species in the epidemiology of Bd and explore its association with the reported amphibian catastrophic declines in the region. We show that Bd is widespread, with a continental prevalence of 23.2%. Its occurrence in the region shows a phylogenetic signal and the probability of infection is determined by ecoregion, preferred habitat and extinction risk hosts' traits. The taxa exhibiting highest Bd occurrence were mostly aquatic amphibians, including Ranidae, Telmatobiidae, Hylodidae, Calyptocephalellidae and Pipidae. Surprisingly, families exhibiting unusually low Bd prevalence included species in which lethal chytridiomycosis and population declines have been described (genera Atelopus, Rhinoderma and Eleutherodactylus). Higher than expected prevalence of Bd occurred mainly in amphibians living in association with mountain environments in the Andes and Atlantic forests, reflecting highly favourable Bd habitats in these areas. Invasive amphibian species (e.g. Lithobates catesbeianus and Xenopus laevis) exhibited high Bd prevalence; thus we suggest using these as sentinels to understand their potential role as reservoirs, vectors or spreaders of Bd that can be subjected to management. Our results guide on the prioritization of conservation actions to prevent further biodiversity loss due to chytridiomycosis in the world's most amphibian diverse region.

中文翻译：

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南美洲的 Batrachochytrium dendrobatidis 感染的合成：面临风险的两栖动物以及重点研究和疾病缓解的领域

由树突杆菌( Bd )引起的两栖类壶菌病已被公认为是导致科学上已知的最灾难性的生物多样性丧失的传染病，南美洲是受影响最严重的地区。我们测试了Bd流行率是否分布在南美洲的宿主分类、生态区、保护状况和栖息地偏好中。在这里，我们基于 21 648 项分子诊断分析、某些物种在 Bd 流行病学中的作用，提供了关于南美洲 Bd 感染程度的综合，并探讨了其与该地区报告的两栖动物灾难性下降的关系。我们证明了Bd分布广泛，大陆流行率为 23.2%。它在该地区的发生显示出系统发育信号，感染概率由生态区、首选栖息地和灭绝风险宿主的特征决定。表现出最高Bd发生率的分类群主要是水生两栖动物，包括Ranidae，Telmatobiidae，Hylodidae，Calyptocephalellidae和Pipidae。令人惊讶的是，表现出异常低Bd流行率的家庭包括已经描述了致命的壶菌病和种群下降的物种（Atelopus属、Rhinoderma和Eleutherodactylus属）。Bd的患病率高于预期主要发生在与安第斯山脉和大西洋森林的山区环境有关的两栖动物中，这反映了这些地区非常有利的Bd栖息地。入侵的两栖动物物种（例如Lithobates catesbeianus和Xenopus laevis）表现出高Bd流行率；因此，我们建议将这些用作哨兵，以了解它们作为可以接受管理的Bd的水库、载体或传播者的潜在作用。我们的结果指导保护行动的优先顺序，以防止在世界上两栖动物种类最多的地区由于壶菌病导致生物多样性进一步丧失。