Talbott Katherine, Wolf Tiffany M, Sebastian Peter, Abraham Meagan, Bueno Irene, McLaughlin Matt, Harris Tara, Thompson Rachel, Pessier Allan P, Travis Dominic
Minnesota Zoo, Apple Valley, MN 55124, USA.
Dis Aquat Organ. 2018 May 7;128(2):93-103. doi: 10.3354/dao03217.
Amphibian populations are in decline worldwide as they face a barrage of challenges, including infectious diseases caused by ranaviruses and the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). Here we describe seasonal dynamics of Bd and ranavirus detection in free-ranging post-metamorphic wood frogs Lithobates sylvaticus, boreal chorus frogs Pseudacris maculata/triseriata, and gray treefrogs Hyla versicolor/chrysoscelis, sampled over a 3 season gradient in Minnesota (USA) wetlands. We detected Bd in 36% (n = 259) of individuals sampled in 3 wetlands in 2014, and 33% (n = 255) of individuals sampled in 8 wetlands in 2015. We also detected ranavirus in 60% and 18% of individuals sampled in 2014 and 2015, respectively. Ranavirus and Bd were detected concurrently in 26% and 2% of animals sampled in 2014 and 2015, respectively. We report clinical signs and associated infection status of sampled frogs; of the clinical signs observed, skin discoloration was significantly associated with ranavirus infection. Using generalized estimating equations, we found that species, season, wetland, and a species × season interaction term were significant predictors of Bd detection, whereas test year approached significance as a predictor of ranavirus detection. The odds of detecting both pathogens concurrently was significantly influenced by species, season, a species × season interaction term, year, and environmental ammonia. We propose an amphibian health monitoring scheme that couples population size surveys with seasonal molecular surveys of pathogen presence. This information is crucial to monitoring the health of remaining strongholds of healthy amphibian populations, as they face an uncertain future of further anthropogenic change.
全球两栖动物数量正在减少，因为它们面临着一系列挑战，包括蛙病毒和两栖类壶菌（Batrachochytrium dendrobatidis，Bd）引起的传染病。在此，我们描述了在明尼苏达州（美国）湿地的一个3季节梯度上采样的自由生活的变态后林蛙（Lithobates sylvaticus）、北方合唱蛙（Pseudacris maculata/triseriata）和灰树蛙（Hyla versicolor/chrysoscelis）中Bd和蛙病毒检测的季节性动态。2014年在3个湿地采样的个体中，36%（n = 259）检测到Bd，2015年在8个湿地采样的个体中，33%（n = 255）检测到Bd。我们还分别在2014年和2015年采样的个体中检测到60%和18%的蛙病毒。2014年和2015年分别有26%和2%的采样动物同时检测到蛙病毒和Bd。我们报告了采样青蛙的临床症状和相关感染状况；在所观察到的临床症状中，皮肤变色与蛙病毒感染显著相关。使用广义估计方程，我们发现物种、季节、湿地以及物种×季节交互项是Bd检测的显著预测因子，而测试年份作为蛙病毒检测的预测因子接近显著水平。同时检测到两种病原体的几率受到物种、季节、物种×季节交互项、年份和环境氨的显著影响。我们提出了一种两栖动物健康监测方案，该方案将种群数量调查与病原体存在的季节性分子调查相结合。这些信息对于监测健康两栖动物种群剩余据点的健康状况至关重要，因为它们面临着进一步人为变化的不确定未来。
