Edwardsiellosis in farmed turbot, Scophthalmus maximus (L.), associated with an unusual variant of Edwardsiella tarda: a clinical, aetiological and histopathological study
Abstract During 2005 and 2010, a survey of edwardsiellosis on eight turbot, Scophthalmus maximus (L.), farms was conducted in China. This report presents the detailed results of the study on this disease. Diseased turbot displayed two distinct types of gross signs: black discoloration of the dorsal...
Published in: | Journal of Fish Diseases |
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Main Authors: | , , |
Other Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2013
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Subjects: | |
Online Access: | http://dx.doi.org/10.1111/jfd.12041 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjfd.12041 https://onlinelibrary.wiley.com/doi/pdf/10.1111/jfd.12041 |
Summary: | Abstract During 2005 and 2010, a survey of edwardsiellosis on eight turbot, Scophthalmus maximus (L.), farms was conducted in China. This report presents the detailed results of the study on this disease. Diseased turbot displayed two distinct types of gross signs: black discoloration of the dorsal skin on the posterior portion of the body; and red cutaneous foci on the ventral side. Internally, the most pronounced clinical signs in all fish examined were enlarged kidneys. The causal agent of the disease was finally proved to be one species of bacterium that was identified as E dwardsiella tarda by physiological and biochemical tests, API 32E and 16S ribosomal RNA sequence analysis. It is noteworthy that unlike the commonly described E. tarda strains, the isolates in this study were non‐motile strains without flagella. A histopathological study revealed that E. tarda infection was systemic in turbot and that kidney showed the most significant pathological changes, including acute focal necrosis, an influx of macrophages and formation of granuloma. The most common histopathological characteristics of this disease are the proliferation of macrophage in various organs and formation of granuloma. In addition, this article also gave background information on the disease and presented the results of virulence tests with the E. tarda strain identified in this study. |
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