Rothermel Betsie B, Miller Debra L, Travis Emilie R, Gonynor McGuire Jessica L, Jensen John B, Yabsley Michael J
Archbold Biological Station, Venus, Florida 33960, USA.
Dis Aquat Organ. 2016 Feb 25;118(2):113-27. doi: 10.3354/dao02965.
Long-term monitoring of amphibians is needed to clarify population-level effects of ranaviruses (Rv) and the fungal pathogen Batrachochytrium dendrobatidis (Bd). We investigated disease dynamics of co-occurring amphibian species and potential demographic consequences of Rv and Bd infections at a montane site in the Southern Appalachians, Georgia, USA. Our 3-yr study was unique in combining disease surveillance with intensive population monitoring at a site where both pathogens are present. We detected sub-clinical Bd infections in larval and adult red-spotted newts Notophthalmus viridescens viridescens, but found no effect of Bd on body condition of adult newts. Bd infections also occurred in larvae of 5 anuran species that bred in our fishless study pond, and we detected co-infections with Bd and Rv in adult newts and larval green frogs Lithobates clamitans. However, all mortality and clinical signs in adult newts and larval anurans were most consistent with ranaviral disease, including a die-off of larval wood frogs Lithobates sylvaticus in small fish ponds located near our main study pond. During 2 yr of drift fence monitoring, we documented high juvenile production in newts, green frogs and American bullfrogs L. catesbeianus, but saw no evidence of juvenile recruitment in wood frogs. Larvae of this susceptible species may have suffered high mortality in the presence of both Rv and predators. Our findings were generally consistent with results of Rv-exposure experiments and support the purported role of red-spotted newts, green frogs, and American bullfrogs as common reservoirs for Bd and/or Rv in permanent and semi-permanent wetlands.
需要对两栖动物进行长期监测，以阐明蛙病毒（Rv）和真菌病原体蛙壶菌（Bd）对种群水平的影响。我们在美国佐治亚州南部阿巴拉契亚山脉的一个山地地点，调查了同时出现的两栖动物物种的疾病动态，以及Rv和Bd感染可能产生的种群统计学后果。我们为期3年的研究具有独特性，它将疾病监测与对两种病原体均存在的一个地点进行的密集种群监测相结合。我们在红斑蝾螈Notophthalmus viridescens viridescens的幼体和成体中检测到亚临床Bd感染，但未发现Bd对成年蝾螈身体状况有影响。Bd感染也发生在我们无鱼研究池塘中繁殖的5种无尾目物种的幼体中，并且我们在成年蝾螈和绿蛙Lithobates clamitans的幼体中检测到Bd和Rv的共同感染。然而，成年蝾螈和幼体无尾目的所有死亡和临床症状与蛙病毒病最为相符，包括在我们主要研究池塘附近的小鱼塘中，北美林蛙Lithobates sylvaticus幼体的死亡事件。在两年的围栏监测期间，我们记录了蝾螈、绿蛙和美国牛蛙L. catesbeianus的高幼体产量，但未发现北美林蛙有幼体补充的迹象。在Rv和捕食者都存在的情况下，这种易感物种的幼体可能遭受了高死亡率。我们的研究结果总体上与Rv暴露实验的结果一致，并支持红斑蝾螈、绿蛙和美国牛蛙作为永久性和半永久性湿地中Bd和/或Rv常见宿主的假定作用。
