Vibrio vulnificus serovar E (formerly biotype 2) is the etiologic agent that is responsible for the main infectious disease affecting farmed eels. Although the pathogen can theoretically use water as a vehicle for disease transmission, it has not been isolated from tank water during epizootics to date. In this work, the mode of transmission of the disease to healthy eels, the portals of entry of the pathogen into fish, and their putative reservoirs have been investigated by means of laboratory and field experiments. Results of the experiments of direct and indirect host-to-host transmission, patch contact challenges, and oral-anal intubations suggest that water is the prime vehicle for disease transmission and that gills are the main portals of entry into the eel body. The pathogen mixed with food can also come into the fish through the gastrointestinal tract and develop the disease. These conclusions were supported by field data obtained during a natural outbreak in which we were able to isolate this microorganism from tank water for the first time. The examination of some survivors from experimental infections by indirect immunofluorescence and scanning electron microscopy showed thatV. vulnificus serovar E formed a biofilm-like structure on the eel skin surface. In vitro assays demonstrated that the ability of the pathogen to colonize both hydrophilic and hydrophobic surfaces was inhibited by glucose. The capacity to form biofilms on eel surface could constitute a strategy for surviving between epizootics or outbreaks, and coated survivors could act as reservoirs for the disease.
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机译： Viulio vulnificus 血清型E（原为生物型2）是引起养殖鳗鱼主要传染病的病原体。尽管从理论上讲，病原体可以将水用作疾病传播的媒介，但迄今为止，尚未在流行病学中将其从储罐水中分离出来。在这项工作中，已经通过实验室和野外实验研究了该疾病向健康鳗鱼的传播方式，病原体进入鱼类的门户及其推定的水库。直接和间接的宿主之间传播，斑块接触挑战和肛管插管的实验结果表明，水是疾病传播的主要媒介，and是进入鳗鱼体内的主要门户。与食物混合的病原体也可以通过胃肠道进入鱼体内并发展成该病。这些结论得到了自然暴发期间获得的现场数据的支持，在这次自然暴发中，我们能够首次从储罐水中分离出这种微生物。通过间接免疫荧光和扫描电子显微镜对实验感染的一些幸存者进行了检查，结果显示出 V。 E. veronificus 血清型E在鳗鱼皮肤表面形成生物膜状结构。体外测定表明，葡萄糖可抑制病原体在亲水和疏水表面定居的能力。在鳗鱼表面形成生物膜的能力可能构成在流行病或暴发之间幸存的策略，而被包膜的幸存者可以充当该疾病的储存库。
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