DAO 139:113-119 (2020)  -  DOI: https://doi.org/10.3354/dao03479

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).

KEY WORDS: Aetiology · Clinical trial · Skin lesions · Vietnam

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Cite this article as: Mayrhofer R, Menanteau-Ledouble S, Pucher J, Focken U, El-Matbouli M (2020) Aeromonas spp. suggested as the causative agents of red spot disease in northern Vietnamese grass carp Ctenopharyngodon idella. Dis Aquat Org 139:113-119. https://doi.org/10.3354/dao03479 Export citation Share:    Facebook - - linkedIn