ABSTRACT: Determining the origin of recurrent outbreaks of fish diseases occurring on fish farms is essential for disease prevention and control measures. In this study, we investigated the potential reservoir role of wild fish species living near salmonid farms which were regularly found to be positive for viral hemorrhagic septicemia virus (VHSV). In addition to VHSV, infectious hematopoietic necrosis virus (IHNV) was also isolated from several pike Esox lucius samples collected from a pond near the salmonid farms of interest. All isolates of VHSV and IHNV analyzed had 100% identical partial glycoprotein gene sequences. VHSV pike strain OO128-25 belonged to the Ia genotype and shared 99.1 to 99.5% nucleotide identity with strains recently isolated from the farms. IHNV pike strain OO121-8, European genotype, appeared to be different from strains from France characterized since the first isolation in 1987. Isolates representative of both viral species were highly virulent in rainbow trout Oncorhynchus mykiss. OO128-25 induced 65% mortality in pike fingerlings, whereas only weak mortality was observed with OO121-8, despite characteristic symptoms in infected fish. High levels of specific antibodies to VHSV and IHNV were detected in adult pike in the absence of clinical signs. Infection of rainbow trout in contact with experimentally VHSV- or IHNV-infected pike fingerlings indicates possible horizontal transmission. These results suggest that pike could act as a reservoir for VHSV and IHNV in the wild, providing additional evidence to explain viral persistence and resurgence in certain areas.

中文翻译：

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梭子鱼Esox lucius对VHSV和IHNV的易感性以及向虹鳟Oncorhynchus mykiss的潜在传播。

摘要：确定在养鱼场中反复发生的鱼病的起源对于疾病预防和控制措施至关重要。在这项研究中，我们调查了生活在鲑鱼养殖场附近的野生鱼类的潜在水库作用，这些鱼类经常被发现对病毒性出血性败血病病毒（VHSV）呈阳性。除VHSV外，还从数个梭子鱼Esox lucius中分离出了传染性造血坏死病毒（IHNV）。从感兴趣的鲑鱼养殖场附近的池塘收集的样品。分析的所有VHSV和IHNV分离株均具有100％相同的部分糖蛋白基因序列。VHSV派克菌株OO128-25属于Ia基因型，与最近从农场分离出的菌株具有99.1％至99.5％的核苷酸同一性。自1987年首次分离以来，欧洲基因型的IHNV派克菌株OO121-8似乎与法国的菌株不同。代表两种病毒的分离株在虹鳟Oncorhynchus mykiss中均具有高毒力。OO128-25诱导派克鱼种的死亡率为65％，而OO121-8仅观察到了较弱的死亡率，尽管受感染的鱼具有特征性症状。在没有临床体征的情况下，在成年派克犬中检测到高水平的针对VHSV和IHNV的特异性抗体。与经VHSV或IHNV感染的派克鱼苗接触的虹鳟鱼感染表明可能存在水平传播。这些结果表明，派克可以在野外充当VHSV和IHNV的贮藏库，为解释某些地区的病毒持续性和复发提供了额外的证据。