Amphibian chytridiomycosis panzootic is ongoing and continuing to have extensive worldwide impact on amphibians. Severity of chytridiomycosis-associated amphibians declines is partly associated with species’ altitudinal ranges. Michoacán state in México harbors 54 amphibian species on a wide range of climates, including high-altitude areas (above 3000 masl), suitable for Bd growth, such as the Monarch Butterfly Biosphere Reserve. This study aims to document patterns of Bd infection on the riparian amphibian community from this high altitude, as well as explore differences in infection rates and seasonality among amphibians’ functional groups. We found Bd at all six sampled sites and registered Bd in eight of the 11 evaluated amphibian species, including two species at global risk. Two functional groups showed the highest Bd prevalence: aquatic salamanders (AqS) (84%) and semiaquatic frogs (SaqF) (76%). A negative relationship between Bd prevalence, temperature and rainfall was found for both groups. This relation was markedly strong (0.95) during the winter, at temperatures below 7 °C and < 50 mm of monthly rainfall. Contrastingly, we found the highest Bd loads at higher temperature (> 10 °C) and moisture (> 100 mm), especially for AqS and SaqF. No dead or sick individuals were found throughout the whole sampling survey. These low pathogenicity levels were probably related to the predominating low environmental temperatures of this high-altitude habitat preventing optimal Bd growth, particularly during winter. Our results suggest that an increase in environmental temperatures in high-altitude areas, as is predicted for the trans-Mexican volcanic belt, might negatively affect amphibian communities by making them more vulnerable because of a likely increase in Bd load.

中文翻译：

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跨墨西哥火山带高海拔栖息地的两栖动物感染了巴氏梭菌

两栖动物泛函菌病正在持续发展，并将继续在全球范围内对两栖动物产生广泛影响。乳杆菌病与两栖动物相关的严重性下降部分与物种的海拔范围有关。墨西哥的米却肯州拥有54种两栖动物，其气候范围很广，包括适合Bd生长的高海拔地区（3000 masl以上），例如帝王蝶生物圈保护区。这项研究旨在记录这种高海拔地区河岸两栖动物群落中Bd感染的模式，并探讨两栖动物功能组之间感染率和季节性的差异。我们在所有六个采样点发现了Bd，并注册了Bd在评估的11种两栖动物物种中，有8种包括全球面临风险的2种。Bd患病率最高的有两个功能组：水sal（AqS）（84％）和半水蛙（SaqF）（76％）。之间的负关系屋宇署盛行，温度和降雨发现两组。在冬季，温度低于7°C和月降雨量<50 mm时，这种关系明显很强（0.95）。相反，我们发现Bd最高在更高的温度（> 10°C）和湿度（> 100 mm）下负载，特别是对于AqS和SaqF。在整个抽样调查中，没有发现死亡或患病个体。这些低致病性水平可能与高海拔栖息地的主要低环境温度有关，阻止了最佳的Bd生长，尤其是在冬季。我们的结果表明，高海拔地区的环境温度升高（如跨墨西哥火山带所预测的那样）可能会导致两栖动物群落更加脆弱，因为其Bd负荷可能会增加，从而使它们变得更加脆弱。