1] University of South Florida, Department of Integrative Biology, Tampa, Florida 33620, USA [2] University of Tampa, Department of Biology, Tampa, Florida 33606, USA [3].
University of South Florida, Department of Integrative Biology, Tampa, Florida 33620, USA.
Nature. 2014 Jul 10;511(7508):224-7. doi: 10.1038/nature13491.
Emerging fungal pathogens pose a greater threat to biodiversity than any other parasitic group, causing declines of many taxa, including bats, corals, bees, snakes and amphibians. Currently, there is little evidence that wild animals can acquire resistance to these pathogens. Batrachochytrium dendrobatidis is a pathogenic fungus implicated in the recent global decline of amphibians. Here we demonstrate that three species of amphibians can acquire behavioural or immunological resistance to B. dendrobatidis. Frogs learned to avoid the fungus after just one B. dendrobatidis exposure and temperature-induced clearance. In subsequent experiments in which B. dendrobatidis avoidance was prevented, the number of previous exposures was a negative predictor of B. dendrobatidis burden on frogs and B. dendrobatidis-induced mortality, and was a positive predictor of lymphocyte abundance and proliferation. These results suggest that amphibians can acquire immunity to B. dendrobatidis that overcomes pathogen-induced immunosuppression and increases their survival. Importantly, exposure to dead fungus induced a similar magnitude of acquired resistance as exposure to live fungus. Exposure of frogs to B. dendrobatidis antigens might offer a practical way to protect pathogen-naive amphibians and facilitate the reintroduction of amphibians to locations in the wild where B. dendrobatidis persists. Moreover, given the conserved nature of vertebrate immune responses to fungi and the fact that many animals are capable of learning to avoid natural enemies, these results offer hope that other wild animal taxa threatened by invasive fungi might be rescued by management approaches based on herd immunity.
新兴真菌病原体对生物多样性构成的威胁大于任何其他寄生群体,导致许多类群(包括蝙蝠、珊瑚、蜜蜂、蛇和两栖动物)数量减少。目前,几乎没有证据表明野生动物可以获得对这些病原体的抵抗力。蛙壶菌是一种与最近全球两栖动物数量减少有关的致病真菌。在这里,我们证明了三种两栖动物可以获得对蛙壶菌的行为或免疫抗性。青蛙在仅仅一次接触蛙壶菌并经历温度诱导的清除后,学会了躲避这种真菌。在随后的实验中,当避免接触蛙壶菌时,以前接触的次数是预测蛙壶菌负担和蛙壶菌诱导死亡率的负指标,也是预测淋巴细胞丰度和增殖的正指标。这些结果表明,两栖动物可以获得对蛙壶菌的免疫力,这种免疫力可以克服病原体诱导的免疫抑制,提高它们的存活率。重要的是,接触死亡真菌会引起与接触活真菌相似程度的获得性抗性。让青蛙接触蛙壶菌抗原可能是一种保护无病原体的两栖动物的实用方法,并有助于将两栖动物重新引入到仍然存在蛙壶菌的野外地点。此外,鉴于脊椎动物对真菌的免疫反应具有保守性,并且许多动物能够学会躲避天敌,这些结果为基于群体免疫的管理方法可能挽救受到入侵真菌威胁的其他野生动物类群提供了希望。