Abstract：
In 2003, the Alaska walleye pollock industry reported product quality issues attributed to an unspecified parasite in fish muscle. Using molecular and histological methods, we identified the parasite in Bering Sea pollock as Ichthyophonus. Infected pollock were identified throughout the study area, and prevalence was greater in adults than in juveniles. This study not only provides the first documented report of Ichthyophonus in any fish species captured in the Bering Sea, but also reveals that the parasite has been present in this region for nearly 20 years and is not a recent introduction. Sequence analysis of 18S rDNA from Ichthyophonus in pollock revealed that consensus sequences were identical to published parasite sequences from Pacific herring and Yukon River Chinook salmon. Results from this study suggest potential for Ichthyophonus exposures from infected pollock via two trophic pathways; feeding on whole fish as prey and scavenging on industry-discharged offal. Considering the notable Ichthyophonus levels in pollock, the low host specificity of the parasite and the role of this host as a central prey item in the Bering Sea, pollock likely serve as a key Ichthyophonus reservoir for other susceptible hosts in the North Pacific.
摘要：
2003年，阿拉斯加角膜白斑pollock行业报告了归因于鱼类肌肉中未指明的寄生虫的产品质量问题。使用分子和组织学方法，我们确定白令海警戒线上的寄生虫是Ichthyophonus.在整个研究区域都发现了感染的pollock，成年人的患病率高于青少年。这项研究不仅提供了在白令海捕获的任何鱼类中的Ichthyophonus的第一份记录报告，但也揭示了寄生虫已经存在于该地区近20年，并不是最近的介绍。对鳕鱼鱼18SrDNA的序列分析表明，共有序列与已发表的太平洋鲱鱼和育空河奇努克鲑鱼的寄生虫序列相同。这项研究的结果表明，通过两种营养途径从被感染的鳕鱼中暴露鱼鱼的潜力；以整条鱼作为猎物为食，并清除工业排放的内脏。考虑到波洛克中明显的鱼鹰水平，寄生虫的低寄主特异性以及该寄主在白令海中作为中心猎物的作用，pollock可能是北太平洋其他易感寄主的重要Ichthyophonus水库。
