Department of Zoology, Oregon State University, Corvallis, OR, USA.
Ecohealth. 2013 Jun;10(2):166-71. doi: 10.1007/s10393-013-0832-8.
The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been associated with global amphibian population declines and extinctions. American bullfrogs (Lithobates catesbeianus) are widely reported to be a tolerant host and a carrier of Bd that spreads the pathogen to less tolerant hosts. Here, we examined whether bullfrogs raised from eggs to metamorphosis in outdoor mesocosms were susceptible to Bd. We experimentally exposed metamorphic juveniles to Bd in the laboratory and compared mortality rates of pathogen-exposed animals to controls (non-exposed) in two separate experiments; one using a Bd strain isolated from a Western toad and another using a strain isolated from an American bullfrog. We wanted to examine whether metamorphic bullfrogs were susceptible to either of these strains. We show that bullfrogs were susceptible to one strain of Bd and not the other. In both experiments, infection load detected in the skin decreased over time, suggesting that metamorphic bullfrogs from some populations may be inefficient long-term carriers of Bd.
新兴真菌病原体蛙壶菌（Batrachochytrium dendrobatidis，Bd）与全球两栖动物种群减少和灭绝有关。据广泛报道，美洲牛蛙（Lithobates catesbeianus）是一种具有耐受性的宿主，也是 Bd 的携带者，可将病原体传播给耐受性较低的宿主。在这里，我们研究了在户外中观生态系统中从卵发育到变态的牛蛙是否容易感染 Bd。我们在实验室中对变态期幼蛙进行了 Bd 暴露实验，并在两个独立的实验中比较了病原体暴露动物与对照组（未暴露）的死亡率；一个实验使用了一种从西方蟾蜍中分离出的 Bd 菌株，另一个实验使用了一种从美洲牛蛙中分离出的菌株。我们想检查变态期牛蛙是否容易感染这两种菌株。我们发现牛蛙容易感染其中一种菌株，但对另一种菌株不易感。在两个实验中，皮肤中的感染负荷随着时间的推移而降低，这表明来自某些种群的变态期牛蛙可能是 Bd 的低效长期携带者。
