• Journal of fish pathology
• /
• v.31 no.1
• /
• pp.35-39
• /
• 2018

Atypical furnculosis caused by atypical Aeromonas salmonicida, is an emerging problem of farming of rockfish (Sebastes schlegeli) in Korea. In this study, protection against atypical furunculosis was compared in rockfish vaccinated with A. salmonicida formalin killed cell (FKC) and adjuvant containing FKC. The formalin inactivated A. salmonicida vaccine provided a low protection of 20% and 10% relative percent survival (RPS) at 44 and 58 days post vaccination. However, addition of adjuvant (squalene and aluminum hydroxide) into inactivated A. salmonicida vaccine clearly enhanced the level of protection showing 70% and 50% RPS at 44 and 58 days post vaccination.

• Korean Journal of Veterinary Service
• /
• v.18 no.1
• /
• pp.22-32
• /
• 1995

A partial characteristics and pathogenicity of Aeromonas salmonicida strain isolated from diseased cultured eel were studied. On the biochemicial characteristics of the isolate strain was classified into atypical Aeromonas salmonicida : the characteristics of the isolate strain differed from those of the subspecies of Achromogenes, masoucida and salmonicida. It strain was named atypical Aeromonas salmonicida EL-1 and it grew at optimal pH 7.5 and l% Nacl. In the pathogenicity test, at one to two days post infection, the motality of artificially infected eels with $1{\times}10^8$ and $1.0{\times}10^7$ cfu/fish group was 100%, and at three days pos-infection, in the $1.0{\times}10^6$ /cfu /fish infected group, the epizootic haemorrhagic ulcer was developed, and haemorragic red sports were formed around abdomen and fins and its died (40%). Total cell protein peptide bands of the A. salmonicida EL-1 were presented betweeon 11.8~102 Kd in molecular weight by the electrophoretic analysis and appeared 28 bands in all. Drug sensitivity of atypical A. salmonicida EL-1 strain was sensitivity to chlorampenicol, gentamicin, kanamycin, streptomycin and sulfamethoxazole /trimethoprim and intermidiate to ampiclin and neomycin resistant to cephalotin, erythromycin, lincomycin and tetracycline.

• Journal of Veterinary Clinics
• /
• v.27 no.3
• /
• pp.289-294
• /
• 2010

Mandarin fish (SSOGARI: Korean name) has emerged as new aquaculture and aquarium fish among Korean native fish species. Unfortunately, this fish could not exempt from infectious agent invasion. As an epidemiological survey, high mortality of mandarin fish (Siniperca scherzeri) observed from a fish farm in Gyeongnam province of South Korea. The major macroscopic sign of the diseased fish was severe multifocal dermal ulceration. Histological observation revealed inflammation, necrosis and colonization of bacteria in various tissues. Seven bacterial isolates from the diseased fish were identified as Aeromonas salmonicida subsp. salmonicida (typical A. salmonicida) using API 20E and 20NE system. However, the polymerase chain reaction (PCR) assay using two different primers (AP and MIY) revealed that the bacterial strains were not typical A. salmonicida, but atypical A. salmonicida. This study demonstrates that PCR assay is a reliable method for the confirmation of atypical A. salmonicida in mandarin fish as compared to biochemical tests. Furthermore, this is the first account of extensive dermatitis in mandarin fish due to atypical A. salmonicida infection, which has high potential in aquaculture and aquarium fish among native fish species.

• Journal of fish pathology
• /
• v.35 no.2
• /
• pp.247-250
• /
• 2022

About 6.7% mortality was reported in a starry flounder (Platichthys stellatus) aquaculture farm in 2022. Most of the diseased fish showed a loss of pectoral fin, hemorrhages on muscle and gills, pale gills, enlarged spleen, and nodules on kidney. Parasites, fungi or viruses (viral hemorrhagic septicemia virus and hirame novirhabdovirus) were not detected from diseased fish. However, numerous bacteria were isolated from liver, spleen and kidney. Nucleotide sequences of the A-protein-encoding virulence array protein gene (vapA) of the bacteria showed 99.93% identity with Aeromonas salmonicida subsp. masoucida. This study is the first report of isolation of atypical A. salmonicida in cultured starry flounder in Korea.

• Journal of fish pathology
• /
• v.32 no.2
• /
• pp.81-89
• /
• 2019

As an epidemiological survey, mortality of marbled rockfish, Sebastiscus tertius observed from a fish farm in Gyeongnam province of South Korea. The major macroscopic sign of the diseased fish was severe multifocal dermal ulceration. Histological observation revealed inflammation, necrosis and colonization of bacteria in various tissues (gill, liver, spleen and kidney). Bacteria was isolated from spleen and kidney in moribund and mortality fish. Seven bacterial isolates from the diseased fish were identified as Aeromonas salmonicida subsp. salmonicida using API 20E and 20NE, API 50CH API ZYM system. Under light microscopy, infected marbled rockfish showed the lifting of the lamella epidermal layer, edematous changes and hypertrophy of epithelial cell in the gill filament. The atrophy of the mucosal fold, erythema in the intestine, and the necrosis of hematopoietic tissue and renal tubule cells with karyolysis were observed in the kidney. In this study was demonstrated the histological reaction of red marbled rockfish infected by Aeromonas salmonicida. Furthermore, this is the first account of extensive dermatitis in Sebastiscus tertius due to atypical A. salmonicida infection, which has high potential in aquaculture among native fish species.

• Journal of fish pathology
• /
• v.28 no.3
• /
• pp.145-155
• /
• 2015

The pathogenecity of atypical Aeromonas salmonicida was studied in healthy Oreochromis niloticus. Inoculum at concentration of $1.5{\times}10^8CFU/ml$ and $3{\times}10^8CFU/ml$ was injected into healthy fish through intramuscular and intraperitoneal injections. Experimentally infected Oreochromis niloticus showed ulceration at the dorsal musculature and trunk region in addition to black coloration, congested gills, exophthalmia, and ocular hemorrhage. Congested liver and kidney were recorded in post-mortem examination. Mortality of the experimentally infected Oreochromis niloticus reached 100% after intramuscular injection at concentration of $3{\times}10^8CFU/ml$. Histopathological investigation of infected organs was also performed. There was a focal area of bundles of skeletal musculature showing hyalinization. In addition, hyperplasia, congestion, and fusion were noticed in the gill lamellae. There was also congestion in the blood vessels in the ocular chamber. Severe congestion was also noticed in the central vein of liver associated with focal aggregation of the melanin pigmented cells in the parenchyma. Degenerative changes were noticed in the epithelial cells lining of kidney tubules. Plant extracts carvacrol and its biological precursor cymene were found to be effective in treating experimentally infected Oreochromis niloticus at concentration of 100 or 200 ppm.