Abstract：
Detection of intestinal parasites in fish typically requires autopsy, resulting in the sacrifice of the fish. Here, we describe a non-lethal method for detecting the tapeworm Eubothrium crassum in fish using anal swabs and real-time PCR detection. Two assays were developed to detect cytochrome oxidase I (COI) mitochondrial DNA and 18S ribosomal DNA sequences of E. crassum, respectively. The assays were tested on swab samples from confirmed pathogen free Atlantic salmon (Salmo salar L.) and on samples from farmed Atlantic salmon, where the presence and intensity of parasites had been established through autopsy. The COI assay was shown to be specific to E. crassum, while the 18S assay also amplified the closely related E. salvelini, a species infecting Arctic charr (Salvelinus alpinus L.) in freshwater. The COI assay detected E. crassum in all field samples regardless of parasite load while the 18S assay failed to detect the parasite in two samples. The results thus demonstrates that this non-lethal approach can effectively detect E. crassum and can be a valuable tool in assessing the prevalence of infection in farmed salmon, aiding in treatment decisions and evaluating treatment effectiveness.
摘要：
检测鱼中的肠道寄生虫通常需要尸检，导致了鱼的牺牲。这里,我们描述了一种使用肛门拭子和实时PCR检测的非致死方法，用于检测鱼类中的the虫。开发了两种方法来检测大肠杆菌的细胞色素氧化酶I（COI）线粒体DNA和18S核糖体DNA序列，分别。对已确认无病原体的大西洋鲑鱼（SalmosalarL.）的拭子样品和养殖的大西洋鲑鱼的样品进行了测试，通过尸检确定了寄生虫的存在和强度。COI分析显示对E.crassum具有特异性，而18S测定也扩增了密切相关的E.salvelini，一种在淡水中感染北极炭（SalvelinusalpinusL.）的物种。COI测定法在所有野外样品中检测到E.crassum，而与寄生虫负载无关，而18S测定法未能在两个样品中检测到寄生虫。因此，结果表明，这种非致死性方法可以有效地检测E.crassum，并且可以成为评估养殖鲑鱼感染率的有价值的工具。协助治疗决策和评估治疗效果。
