Olstad K, Robertsen G, Bachmann L, Bakke T A
Natural History Museum, Department of Zoology, University of Oslo, PO Box 1172, NO-0318 Oslo, Norway.
Parasitology. 2007 Apr;134(Pt 4):589-97. doi: 10.1017/S0031182006001715. Epub 2006 Dec 14.
The monogenean ectoparasite, Gyrodactylus salaris Malmberg, 1957, has had a devastating effect on wild Atlantic salmon (Salmo salar) since its introduction to Norway in the mid-1970s. In Lake Pålsbufjorden, southern Norway, upstream of the stretches of the River Numedalslågen with anadromous Atlantic salmon, a resident Arctic charr (Salvelinus alpinus) population has been reported to be infected with G. salaris which is viable in the absence of its normal host, the Atlantic salmon. Currently, there is no record of G. salaris infecting Atlantic salmon in the downstream sections of the River Numedalslågen. We studied experimentally the infectivity and reproductive capacity of G. salaris from Lake Pålsbufjorden on wild and hatchery-reared Atlantic salmon as well as on Arctic charr and rainbow trout (Oncorhynchus mykiss). Arctic charr and rainbow trout were moderately susceptible, whereas the Atlantic salmon stocks from River Numedalslågen and River Drammenselva were innately resistant to only slightly susceptible. Thus, the G. salaris from Arctic charr in Lake Pålsbufjorden is considered non-pathogenic to Atlantic salmon. This is the first observation of variation in host preference among Norwegian G. salaris populations. The observed differences in virulence between G. salaris populations could have important consequences for the international legislation and management of Atlantic salmon.
单殖吸虫外寄生虫，鲑三代虫（Gyrodactylus salaris Malmberg，1957）自20世纪70年代中期引入挪威以来，对野生大西洋鲑（Salmo salar）产生了毁灭性影响。在挪威南部的帕尔斯布约尔登湖，努默达尔斯拉根河有溯河洄游大西洋鲑的河段上游，据报道当地的北极红点鲑（Salvelinus alpinus）种群感染了鲑三代虫，这种寄生虫在没有其正常宿主大西洋鲑的情况下也能存活。目前，没有记录表明鲑三代虫感染了努默达尔斯拉根河下游的大西洋鲑。我们通过实验研究了来自帕尔斯布约尔登湖的鲑三代虫对野生和孵化场养殖的大西洋鲑以及北极红点鲑和虹鳟（Oncorhynchus mykiss）的感染力和繁殖能力。北极红点鲑和虹鳟中度易感，而来自努默达尔斯拉根河和德拉门塞尔瓦河的大西洋鲑种群天生具有抗性或仅轻微易感。因此，帕尔斯布约尔登湖北极红点鲑身上的鲑三代虫被认为对大西洋鲑无致病性。这是首次观察到挪威鲑三代虫种群之间宿主偏好的差异。观察到的鲑三代虫种群毒力差异可能对大西洋鲑的国际立法和管理产生重要影响。
