Jørgensen Anders, Torp Kari, Bjørland Marie A, Poppe Trygve T
Norwegian Veterinary Institute, PO Box 750 Sentrum, 0106 Oslo, Norway.
Dis Aquat Organ. 2011 Nov 3;97(1):57-63. doi: 10.3354/dao02404.
Spironucleus salmonicida is a diplomonad flagellate known to cause systemic infections in farmed salmonids. In northern Norway, outbreaks of spironucleosis in farmed Atlantic salmon Salmo salar have been a recurring problem. Common to all these outbreaks was the origin of smolts: all came from the same farm. In the present study, wild Arctic char Salvelinus alpinus and brown trout Salmo trutta were sampled from the lakes used as a water source for the smolt supplier. In addition, smolt and three-spined sticklebacks Gasterosteus aculeatus were sampled from the smolt farm. Bile and intestinal contents from the sampled fish were examined by light microscopy and PCR. Spironucleus salmonicida was identified in both wild Arctic char and brown trout from the lakes used as water sources by the smolt farm, suggesting that the farmed fish were exposed to this pathogen before transfer to the sea. Spironucleus barkhanus and Spironucleus salmonis were also identified in the sampled fish. The present study also demonstrated that infections with multiple Spironucleus species are present in wild salmonids. No indications of disease related to diplomonad infections were observed in the wild fish, suggesting that wild salmonids are reservoir hosts of Spironucleus salmonicida.
鲑鱼螺旋体是一种双滴虫鞭毛虫，已知会在养殖鲑科鱼类中引发全身性感染。在挪威北部，养殖大西洋鲑（Salmo salar）的螺旋体病暴发一直是个反复出现的问题。所有这些暴发事件的共同点是幼鲑的来源：均来自同一个养殖场。在本研究中，从用作幼鲑供应商水源的湖泊中采集了野生北极红点鲑（Salvelinus alpinus）和褐鳟（Salmo trutta）。此外，还从幼鲑养殖场采集了幼鲑和三刺鱼（Gasterosteus aculeatus）。通过光学显微镜和聚合酶链反应对采集的鱼的胆汁和肠道内容物进行了检查。在用作幼鲑养殖场水源的湖泊中的野生北极红点鲑和褐鳟中均鉴定出了鲑鱼螺旋体，这表明养殖鱼类在转移到海洋之前就已接触到这种病原体。在采集的鱼中还鉴定出了巴尔卡纳螺旋体和鲑鱼螺旋体。本研究还表明，野生鲑科鱼类中存在多种螺旋体感染。在野生鱼类中未观察到与双滴虫感染相关的疾病迹象，这表明野生鲑科鱼类是鲑鱼螺旋体的储存宿主。
