Data from: Metabolites from the fungal pathogen Batrachochytrium dendrobatidis (Bd) reduce Bd load in Cuban treefrog tadpoles

Batrachochytrium dendrobatidis (Bd) has been associated with massive amphibian population declines worldwide. Wildlife vaccination campaigns have proven effective for mitigating damage from other pathogens, and there is evidence that adult frogs can acquire resistance to Bd when exposed to killed Bd zoospores and the metabolites they produced. Here, we investigated whether Cuban treefrogs tadpoles (Osteopilus septentrionalis) can gain protection from Bd through exposure to a prophylaxis treatment composed of killed zoospores or soluble Bd metabolites. We used a 2x2 factorial design, crossing the presence or absence of killed zoospores with the presence or absence of Bd metabolites. All hosts were subsequently exposed to live Bd to evaluate susceptibility. Exposure to killed zoospores did not induce a protective response. However, tadpoles exposed to Bd metabolites had significantly lower Bd intensity and prevalence than tadpoles that were not exposed to metabolites. The metabolites Bd produce pose no risk of Bd infection and therefore make an epidemiologically safe prophylaxis treatment, protecting tadpoles against Bd. This work provides a promising potential for protecting amphibians in the wild as a disease management strategy for controlling Bd associated declines.

蛙壶菌（Batrachochytrium dendrobatidis，简称Bd）目前已被证实与全球两栖动物种群的大规模衰退存在密切关联。野生动物疫苗接种策略已被证实可有效缓解其他病原体造成的危害，且已有研究显示，成年蛙在接触灭活的Bd游动孢子及其分泌的代谢产物后，能够获得针对Bd的抗性。本研究以古巴雨蛙蝌蚪（学名：Osteopilus septentrionalis）为研究对象，探究其是否可通过接触由灭活游动孢子或可溶性Bd代谢产物构成的预防性处理方案，获得抵御Bd的保护力。本研究采用2×2析因实验设计，设置灭活游动孢子存在/缺失与Bd代谢产物存在/缺失的四组交叉对照。随后将所有受试个体暴露于活Bd环境中，以评估其感染易感性。实验结果表明，接触灭活游动孢子并未诱导产生保护性免疫应答。相较之下，接触Bd代谢产物的蝌蚪，其体内Bd载量与感染率均显著低于未接触代谢产物的对照组个体。Bd分泌的代谢产物本身不会引发Bd感染，因此是一种符合流行病学安全标准的预防性处理方案，能够有效保护蝌蚪免受Bd侵染。本研究为通过疾病管理策略防控Bd相关的两栖动物种群衰退、进而保护野生两栖动物提供了极具应用前景的潜在途径。