Laboratory of Aquatic Pathobiology, Department of Veterinary and Animal Science, University of Copenhagen, Stigbøjlen 7, 1870, Frederiksberg C, Denmark.
Aquamind, Gersonsvej 7, 2900, Hellerup, Denmark.
Sci Rep. 2020 Sep 30;10(1):16143. doi: 10.1038/s41598-020-72715-y.
Surveillance and diagnosis of parasitic Bonamia ostreae infections in flat oysters (Ostrea edulis) are prerequisites for protection and management of wild populations. In addition, reliable and non-lethal detection methods are required for selection of healthy brood oysters in aquaculture productions. Here we present a non-lethal diagnostic technique based on environmental DNA (eDNA) from water samples and demonstrate applications in laboratory trials. Forty oysters originating from Limfjorden, Denmark were kept in 30 ppt sea water in individual tanks. Water was sampled 6 days later, after which all oysters were euthanized and examined for infection, applying PCR. Four oysters (10%) were found to be infected with B. ostreae in gill and mantle tissue. eDNA purified from the water surrounding these oysters contained parasite DNA. A subsequent sampling from the field encompassed 20 oysters and 15 water samples from 5 different locations. Only one oyster turned out positive and all water samples proved negative for B. ostreae eDNA. With this new method B. ostreae may be detected by only sampling water from the environment of isolated oysters or isolated oyster populations. This non-lethal diagnostic eDNA method could have potential for future surveys and oyster breeding programs aiming at producing disease-free oysters.
监测和诊断贻贝寄生虫 Bonamia ostreae 的感染是保护和管理野生种群的前提条件。此外，在水产养殖生产中，还需要可靠的、非致死性的方法来选择健康的亲贝。在这里，我们提出了一种基于水样环境 DNA（eDNA）的非致死性诊断技术，并在实验室试验中进行了演示。40 只来自丹麦利姆弗日湾的贻贝被放置在 30 ppt 的海水中的单独水槽中。6 天后取样，然后对所有贻贝进行安乐死，并通过 PCR 检查感染情况。在鳃和套膜组织中发现 4 只贻贝（10%）感染了 B. ostreae。从这些贻贝周围的水中提取的 eDNA 含有寄生虫 DNA。随后从现场采集了 20 只贻贝和 5 个不同地点的 15 个水样。只有一只贻贝呈阳性，所有水样均未检出 B. ostreae 的 eDNA。使用这种新方法，可以通过仅从孤立贻贝或孤立贻贝种群的环境中采集水样来检测 B. ostreae。这种非致死性的 eDNA 诊断方法可能对未来旨在生产无病贻贝的调查和贻贝养殖计划具有潜力。
