Evaluating environmental DNA-based quantification of ranavirus infection in wood frog populations
Evaluating environmental DNA-based quantification of ranavirus infection in wood frog populations
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DOI：
10.1111/1755-0998.12461
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发表时间：
2016-03-01
影响因子：
7.7
通讯作者：
Brunner, Jesse L.
中科院分区：
文献类型：
--
作者：
Hall, Emily M.;Crespi, Erica J.;Brunner, Jesse L.
监测野生动物种群的疾病时会出现各种挑战。组织采样可能会对宿主造成侵入，并且获得足够的样本量可能既昂贵又耗时，特别是对于稀有物种和病原体流行率较低的情况。基于环境 DNA (eDNA) 的病原体检测是水生群落监测的替代方法，可以规避许多此类问题。蛙病毒是变温脊椎动物的新病原体，与两栖动物种群的死亡有关。检测蛙病毒感染至关重要，但非致命方法存在上述问题，并且容易出现假阴性。我们报告了基于 eDNA 的蛙病毒现场检测的可行性和有效性。我们比较了从池塘水中收集的 eDNA 样本中的蛙病毒滴度与林蛙 (Lithobates sylvaticus；n=5) 蝌蚪的滴度，该蝌蚪在该物种占主导地位的地点（n=20 个池塘访问）。我们研究了当池塘中存在感染时，是否可以在池塘水中的 eDNA 中检测到蛙病毒 DNA，以及 eDNA 样本中检测到的病毒滴度是否与蝌蚪中蛙病毒感染的流行率或强度相关。通过三个 250mL 水样，我们能够在所有受感染幼虫的访问中检测到病毒（诊断灵敏度为 0.92）。此外，我们发现病毒 eDNA 滴度与幼虫组织中的滴度之间存在密切关系。 eDNA 滴度在观察到死亡之前增加，之后下降，并且在发生死亡的池塘中高出两个数量级。我们的结果表明，eDNA 可用于检测野生动物和水产养殖中的蛙病毒感染。
A variety of challenges arise when monitoring wildlife populations for disease. Sampling tissues can be invasive to hosts, and obtaining sufficient sample sizes can be expensive and time-consuming, particularly for rare species and when pathogen prevalence is low. Environmental DNA (eDNA)-based detection of pathogens is an alternative approach to surveillance for aquatic communities that circumvents many of these issues. Ranaviruses are emerging pathogens of ectothermic vertebrates linked to die-offs of amphibian populations. Detecting ranavirus infections is critical, but nonlethal methods have the above issues and are prone to false negatives. We report on the feasibility and effectiveness of eDNA-based ranavirus detection in the field. We compared ranavirus titres in eDNA samples collected from pond water to titres in wood frog (Lithobates sylvaticus; n=5) tadpoles in sites dominated by this one species (n=20 pond visits). We examined whether ranavirus DNA can be detected in eDNA from pond water when infections are present in the pond and if viral titres detected in eDNA samples correlate with the prevalence or intensity of ranavirus infections in tadpoles. With three 250mL water samples, we were able to detect the virus in all visits with infected larvae (0.92 diagnostic sensitivity). Also, we found a strong relationship between the viral eDNA titres and titres in larval tissues. eDNA titres increased prior to observed die-offs and declined afterwards, and were two orders of magnitude higher in ponds with a die-off. Our results suggest that eDNA is useful for detecting ranavirus infections in wildlife and aquaculture.