• Journal of Environmental Science International
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• v.9 no.5
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• pp.365-368
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• 2000

The antibacterial effect amino acid-copper(II) surfactant on fish pathogens was studied. Fish pathogens of Edwardsiella tarda Vibrio anguillarum Aeromonas hydrophila and Streptococcus sp. were selected cultured in nutrient agar and adjusted at $2{\times}10^5~10^6 CFU/$m\ell$$ in phosphate buffer saline before the addtion of amino acid-copper(II) surfactant with different concentrations. All tested pathogens died within 1 hour with 1 ppm of amino acid-copper(II) surfactant. In comparison with formalin and ET. amino acid-copper (II) surfactnat was more effective in antibacterial capacity.

• Korean Journal of Veterinary Research
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• v.37 no.1
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• pp.203-212
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• 1997

Antibacterial efficacy and safety of copper sulfate pentahydrate (5% solution) was evaluated in laboratory and field studies for disinfection of some fish bacterial pathogens in cultured fish, flounder(Paralichthys olivaceus), mirror carp(Cyprinus carpio), gold fish(Carrassius auratus) and eel(Anguilla japonica). Dipping of fishes for acute toxicity was performed for a period of 48h, and the TLm value(median tolerance limit) were 4.0ppm in mirror carp and flounder, 4.4ppm in rainbow trout, and 10.0ppm in gold fish. After exposure below than TLm value for 1 month, no side effects and histopathological changes were observed. The test drug were shown high antibacterial activities against most bacterial pathogens by exposure in the laboratory and field trials. However, Aeromonas salmonicida showed a resistance to the dosage. We can prevent outbreaks of bacterial diseases of fish by the dosage of 1ppm for 6hr and the test drug is thought to be used effectively and widely as a disinfectant against most bacterial fish pathogens.

• Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.28.1-28.7
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• 2016

Background: Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm) on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results: We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and $68.4J\;cm^{-2}$, respectively, produced one log reduction in the bacterial populations), whereas Streptococcus parauberis was the least susceptible ($153.8J\;cm^{-2}$ per one log reduction). In general, optical density (OD) values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions: This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.539-546
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• 2019

The major cultured marine fishes in sea off the coast Gyeongsangnam-do Province, South Korea, were assessed and included 9.3% rockfish Sebastes schlegelii, 7.8% red seabream Pagrus major, and 2.1% rock bream Oplegnathus fasciatus. The number of insurance payments related to disease mortality in cultured fish in 2017 was fourfold that in 2016. Economic loss in aquaculture due to disease in cultured fish is high and represents an important inhibitory factor affecting marine fishery productivity. In 2018, diseases led to severe production losses in several aquaculture species: 40.0% in rockfish, 11.4% in olive flounder Paralichthys olivaceus, 10.0% in filefish Thamnaconus modestus, and 9.3% in red seabream. Fish-parasitic pathogens such as Microcotyle sebastis, Alella spp., and Dactylogyrus spp. enter mainly via the gills and skin surface. Among bacterial pathogens, Vibrio species were most common, with Vibrio harveyi being the dominant species causing infections in these fishes. The bacterium Lactococcus garvieae is thought to exhibit host specificity in fish. The fish species in the present study exhibited a higher tendency for infection by heterologous pathogens than by a single pathogen; therefore, it is necessary to devise new strategies for treating diseases in cultured fish.

• Journal of fish pathology
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• v.33 no.1
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• pp.91-95
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• 2020

Fish bacterial diseases have spread and caused serious problem for cultured marine fish in Korea. The important bacterial disease affecting mariculture such as olive flounder (Paralichthys olivaceus) are caused by Edwardsiella tarda, Vibrio scophthalmi and Streptococcus parauberis. For the bacterial disease protection in aquaculture industry, the water treatment is needed in aquaculture system. During the last decades atmospheric pressure non-thermal plasma in contact with liquids have received a lot of attention of environmental and medical application. In this study, we determined the disinfectant effect in seawater and three major fish bacterial disease pathogens by using low frequency plasma treatment. Three fish bacteria (E. tarda, V. schophthalmi, S. parauberis) were not detected within 16 min, 150 min and 270 min of 20 L, 500 L and 1 ton seawater post low frequency plasma treatment, respectively. Three major fish bacterial disease pathogens were not detected within 2 min after the low frequency plasma treatment, suggesting that the low frequency plasma possess disinfectant effectiveness.

• Journal of fish pathology
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• v.22 no.1
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• pp.75-83
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• 2009

Disease surveillance was performed to monitor the prevalence of fish pathogens in wild marine fish caught in coastal offshore water from February to October in 2008. A total of 401 fish samples were collected at set net or fish market at landing port on the coast of Pohang, Geoje, Yeosu and Jeju. In this study, 17 kinds of fish pathogens were isolated from 152 fish samples. The detection rates of parasites, bacteria or viruses were 21.4%, 17.0% and 2.7%, respectively. The detected parasites were Scutica, Trichodina, Cryptocaryon, Dactylogyrus, Microcotyle, Benedenia, Bivagina, Heteraxin, Caligus, Epistylis and nematode. The dominant bacterial pathogens were Vibrio, Streptococcus, Photobacterium and Psuedomonas. Red sea bream iridovirus (RSIV) and lymphocystis disease virus (LDV) were detected in 6 species of fish virus examined in this study. The detection rates of fish pathogens from Scorpaenidae, Monacanthidae, Pleuronectidae, Sparidae and Carangidae investigated over 30 samples were 59.2%, 48.4%, 34.2%, 30.6% and18.2%, respectively.

• Journal of fish pathology
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• v.35 no.2
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• pp.205-214
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• 2022

In recent years, there have been many studies investigating changes in animal behavior using video tracking technology to track motion. However, there have been very few studies and results on changes in the behavior of fish infected with a pathogen. Therefore, the present study attempted to analyze the behavior of angelfish (Pterophyllum scalare) infected with bacterial pathogens using video tracking. Two cameras were placed in front of the water tank to obtain behavior data, and tracking was performed for three days until the day of death. Data such as average speed, changes in speed, the locations of the fish in the tank, and fractal dimension were statistically analyzed based on the fish speed and location in the tank of the fish. For bacterial infection, an individual angelfish was intraperitoneally injected with approximately 10⁶ CFU ml^-1 of Aeromonas hydrophila or Edwardsiella piscicida. The experiment was carried out five times for each group. Fish infected with the bacterial pathogens showed a tendency to increase in speed and to spend more time in the upper part of the tank one or two days before death. On the day the fish died, the average speed, changes in speed, and the fractal dimension value were significantly lower than the corresponding values in the control group, and the fish also remained in the lower part of the tank. Our results indicated that behavioral changes in fish could be successfully detected earlier than death using video tracking technology, and that this method presents potential for disease monitoring in aquaculture.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.527-547
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• 2020

Fish pathogens cause not only economic damages to fish farming but also infectious pathogens known as a zoonotic agent. Since the continued use of antibiotics to control fish pathogens entails side effects, materials of natural origin need to be developed. The purpose of this study is to discover coniferous essential oils with excellent antibacterial effects in order to develop antibiotic alternatives. We have extracted essential oils using hydro-distillation from the leaves of Abies holophylla, Pinus thunbergii, Pinus parviflora, Tsuga sieboldii, and Pinus rigitaeda, which are all Pinaceae family. And, we have evaluated antibacterial activity with the extracted essential oils against Edwardsiella tarda, Photobacterium damselae, Streptococcus parauberis, and Lactococcus garvieae, which are fish pathogens. As a result, the essential oils from A. holophylla and P. thunbergii showed the selectively strong antibacterial activity against E. tarda and P. damselae, which are gram-negative bacteria. From GC-MS analysis, it was identified that main component of A. holophylla essential oils are (-)-bornyl acetate (29.45%), D-limonene (20.47%), and camphene (11.73%), and that of P. thunbergii essential oils is α-pinene (59.81%). In addition, we found three compounds: neryl acetate, (-)-borneol, and (-)-carveol, which are oxygenated monoterpenes. These exist in a very small amount but exhibit the same efficacy as essential oil. Therefore, we expect that A. holophylla and P. thunbergii essential oils having excellent growth inhibitory effect against gram-negative fish pathogens can be used as biological products such as feed additives and fishery products.

• Natural Product Sciences
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• v.19 no.1
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• pp.61-65
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• 2013

A bioassay-guided fractionation of the extract of the fungus Paecilomyces variotii, which was derived from the giant jellyfish Nemopilema nomurai, led to the isolation of antibacterial compounds viriditoxin and its monomeric subunit semi-viriditoxin. Viriditoxin showed significant antibacterial activity against several marine fish and human pathogens including MDR strains. Significant potencies against resistant pathogens such as VRE Enterococcus faecium, VRE Enterococcus faecalis, and MRSA were highly interesting. Viriditoxin also showed notable antibacterial activity against the fish pathogen Streptococcus iniae. Its potency was over 100-fold higher than oxytetracycline which is employed as a general antibiotic for aquaculture.

• Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.5.1-5.9
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• 2019

Background: Live fish import may lead to the unintended introduction of pathogens. We examined the monthly distribution of microbial pathogens in ornamental finfish imported into South Korea over a 6-month period. Results: Vibrio alginolyticus was detected in one lemon damsel in June and July; V. vulnificus was detected in one lemon damsel, one caerulean damsel, and one pearl-spot chromis and one ocellaris clownfish in July, April, and May, respectively; Photobacterium damselae was detected in one ocellaris clownfish and one caerulean damsel in June and July, respectively; V. anguillarum was detected in one pearl-spot chromis in February; V. harveyi was detected in one ocellaris clownfish and two mandarin fish in February and April, respectively; Yersinia ruckeri was detected in a pearlscale goldfish group in June and July and in two colored carp groups in July; and Lactococcus garvieae was detected in a lemon damsel group and a sutchi catfish group in July and May, respectively. European catfish virus, the only viral pathogen detected, was found in two sutchi catfish groups in May. Conclusion: This study is the first to identify pathogenic species and the presence or absence of pathogens (non-quarantine diseases) in imported ornamental finfish. These results demonstrate that various pathogens with the potential to harm indigenous fish populations can accompany ornamental finfish imported into South Korea.