ABSTRACT: In northern Vietnam, a disease called ‘red spot disease’ has been causing high morbidity and mortality in populations of farmed grass carp Ctenopharyngodon idella for about 2 decades. The name ‘red spot disease’ refers to a condition characterised by haemorrhagic lesions, reddening and ulceration of the skin. Eight different bacterial isolates, namely Aeromonas hydrophila, A. sobria, Staphylococcus epidermidis, Vibrio alginolyticus, Pseudomonas fluorescens, P. luteola, Citrobacter freundii and P. putida, were isolated from diseased grass carp and used for experimental infection of the same species. Fish were challenged with the different bacterial isolates both by immersion and intramuscular injection. Different concentrations of bacteria were tested to evaluate their pathogenicity. Injection with 1 × 10⁵ CFU of A. hydrophila and A. sobria resulted in clinical signs identical to those of red spot-diseased grass carp in Vietnam. None of the other bacterial isolates tested caused any morbidity or mortality in fish challenged either intramuscularly (1 × 10⁶ CFU) or by bath immersion (1 × 10⁶ or 1 × 10⁸ CFU ml^-1).

中文翻译：

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气单胞菌 建议作为越南北部草鱼Ctenopharyngodon idella的红色斑点病的病原。

摘要：在越南北部，约有20年之久，一种称为“红斑病”的疾病在养殖的草鱼Ctenopharyngodon idella种群中引起高发病率和死亡率。名称“红斑病”是指以出血性病变，皮肤发红和溃疡为特征的疾病。八个不同的细菌分离株，分别是嗜水气单胞菌，曲霉，表皮葡萄球菌，溶藻弧菌，荧光假单胞菌，黄体假单胞菌，弗氏柠檬酸杆菌和恶臭假单胞菌。，从患病的草鱼中分离出来，用于相同物种的实验性感染。通过浸没和肌肉内注射，用不同的细菌分离物攻击鱼。测试了不同浓度的细菌以评估其致病性。注射1×10 ⁵ CFU的嗜水气和A. sobria导致临床症状的那些相同的越南红斑病变草鱼。测试的其他细菌分离株均未引起肌肉内（1×10 ⁶ CFU）或浸浴（1×10 ⁶或1×10 ⁸ CFU ml ^-1）攻击的鱼的发病或死亡。