• Journal of fish pathology
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• v.23 no.1
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• pp.137-143
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• 2010

Hot water extracts of 5 herbs were tested in-vitro for anti-bacterial, anti-fungal, anti-parasitical effects for possible use against fish diseases. Skullcap, Scutellaria baicalensis, was the most effective herb in these 5. The effects of skullcap in cultured flounder were examined for various physiological responses and bacterial disease-prevention follow as feeding skullcap absorbed diet for 4, 8, 12weeks. There were not any significant effects in physiological responses, except beneficial action of growth promotion. No definitive preventive activity was observed with experimental feeding of the extract against infected flounder. As we could not confirm in-vivo antibacterial effects of skullcap in flounder despite its in-vitro efficacy, further studies are needed to define the in-vivo efficacy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.634-643
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• 2021

Han In-jin (Artemisia iwayomogi Kitamura) and Cham Dang-gwi (Angelica gigas Nakai) exhibit antibacterial, antiparasitic, antifungal, and antiviral properties in vitro. In this study, mixture of the extracts of these two medicinal plants was absorbed on pellets. Thereafter, these pellets were fed to olive flounder Paralichthys olivaceus for 12 weeks at laboratory (1^st experiment) and 24 weeks at field test (2^nd experiment), and the immune activity and disease resistance properties of the extracts were examined. It was observed that lysozyme activities of plasma, spleen, and kidney improved after 12 weeks. Furthermore, when the olive flounders were artificially infected with bacterial pathogens, their cumulative mortality decreased in the group that was fed the extracts for 12 weeks compared to that in control group, and the relative percent survival also improved. This study concluded that mixture of Han In-jin and Cham Dang-gwi extracts provides disease resistance in vivo.

• Journal of fish pathology
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• v.20 no.1
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• pp.61-70
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• 2007

The epidemiological study was performed to survey the prevalence of bacterial disease of cultured olive flounder, Paralichthys olivaceus from October, 2004 to August, 2006 in Korea. A total of 1,271 of fish samples were collected at random includes fish exhibiting clinical signs of the disease in question. The total 331 samples among 738 cases of infectious diseases were infected with 366 bacteria isolates including Vibrio spp. (42.1%), Streptococcus spp. (16.9%), Edwardsiella tarda (12.3%), Photobacterium damselae subsp. damselae (8.2%), Pseudomonas spp. (2.2%) or others (18.3%). Vibrio spp. and P. damselae subsp. damselae were continually isolated through all seasons but Streptococcus spp. and E. tarda were mainly isolated from May to November. The 206 cases were showed mixed infection with other bacteria (3.6%), parasites (31.4%) or virus (41.7%); Vibrio spp. (n=21), Streptococcus spp. (n=13), Trichodina (n=76), Scutica (n=31), VNNV (n=112), VHSV (n=46).

• Journal of fish pathology
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• v.10 no.2
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• pp.143-152
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• 1997

The effect of $\beta$-glucan as an immunostimulant to increase resistance to bacterial diseases by enhancing non-specific defense mechanism in rockfish (Sebastes schlegeli) was examined by oral and bath administration. After oral or bath administration with $\beta$-glucan, the injection challenges with Vibro ordalii, Staphylococcus epidermidis and Edwardsiella tarda were performed to assess $\beta$-glucan efficacy. After injection of V. ordalii, oral administration for 30 days with 1% $\beta$-glucan showed 25% of survival rate. But all control fish died within 3 days after the injection. After injection of S, epidermidis, oral administration group for 20 and 30 days showed a remarkably increased survival rate of 95%. But oral administration of $\beta$-glucan to rockfish did not induce protection against experimental E. tarda infection. $\beta$-Glucan bath administration with or without formalin-killed V. ordalii showed that no protection was observed at 10 days after challenge. The results show that $\beta$-glucan to rockfish was effective to increase survival rate of bacterial infections of S. epidermidis and V. ordalii but not against E. tarda.

• Journal of fish pathology
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• v.20 no.2
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• pp.179-187
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• 2007

Hydrolysis compound of cactus of opuntia genus, Opuntia ficus-indica var. saboten Makino, has predominant anti-bacterial, anti-fungal effects. In this study, we wont to know a preventive effects of bacterial disease on cultured flounder using the compound (MBT-01108), and physical and physiological responses of those fishes were examined additionally. The MBT-01108 shown any side effect on physical, hematological and histological conditions of fishes. Immunologically, CL (chemiluminescense) response were appeared at MBT-01108 (0.1%) feeding group for 4 weeks. The results of comparative livability at a experimental infection with E.tarda and S.iniae were 82.5% and 13.5% at 4 weeks MBT (0.1%) feeding group.

• Journal of fish pathology
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• v.7 no.2
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• pp.105-112
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• 1994

A new bacterial infection occurred among the cultured Korean catfish, Silurus asotus, in Chunbuk prefecture, Korea, 1993. This disease produced about 30% mortality in the fish for 4 months. The diseased fish was swimming listless at the water surface with head up and tail down, sometimes spinnig in circles. The most outstanding clinical sign was ulceration on the skull and at the base of the pectoral fins. The causative organism was isolated from the brain, kidney, spleen and liver of diseased fish, and identified as Edwardsiella icaluri by the biochemical and biophysical characteristics. After intraperitoneal innoculaton of the isolate, the pathogenicity was proved positive for Korean catfish, S. asotus, and channel catfish, Ictalurus punctatus, but negative for carp, Cyprinus carpio.

• Journal of fish pathology
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• v.21 no.3
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• pp.271-278
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• 2008

The epidemiological study was performed to survey the prevalence of 5 bacterial, 6 viral and 5 parasitic disease of cultured olive flounder, Paralichthys olivaceus in Pohang, Ulsan∙Gijang, Keoje and Wando area of Korea from February to December, 2007. The disease frequency of size groups were as follows; Among the 1,218 fish samples, less than 10 cm (67.6%), 11~20 cm (70.2%), 21~30 cm (73.4%), 31~40 cm (77.6%), above 41 cm (88.2%). The highest detection rates of pathogens were recorded in samples from August and Ulsan. The detection rates of parasites, bacteria or viruses were 43.2%, 38.8% and 24.4%, respectively. The distribution of specific diseases showed that detection rates of diseases occurring the most frequently during the study period were Trichodina (33.1%), viral nervous necrosis virus (16.0%), Vibrio (9.7%), Scutica (10.1%), Ichthyobodo (5.7%).

• 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.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.71-80
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• 2022

In the past, fish diseases were bacterial in aqua farms, but in recent years, the frequency of fish diseases has increased as they have become viral and mixed. Viral diseases in an enclosed space called a aqua farm have a high spread rate, so it is very likely to lead to mass death. Fast identification of fish diseases is important to prevent group death. However, diagnosis of fish diseases requires a high level of expertise and it is difficult to visually check the condition of fish every time. In order to prevent the spread of the disease, an automatic identification system of diseases or fish is needed. In this paper, in order to improve the performance of the disease identification system of Paralichthys olivaceus based on deep learning, the existing pre-processing method is compared and tested. Target diseases were selected from three most frequent diseases such as Scutica, Vibrio, and Lymphocystis in Paralichthys olivaceus. The RGB, HLS, HSV, LAB, LUV, XYZ, and YCRCV were used as image pre-processing methods. As a result of the experiment, HLS was able to get the best results than using general RGB. It is expected that the fish disease identification system can be advanced by improving the recognition rate of diseases in a simple way.

• Journal of fish pathology
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• v.37 no.1
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• pp.97-110
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• 2024

The Serranidae is high-quality fish species with good meat quality and is traded at high price, and is attracting attention in South Korea as a cultured species that creates high added value. However, the high-density fish farming for mass production increases the risk of mass mortality due to infectious diseases, leading to enormous economic losses. Therefore, in order to safely prevent and protect farmed fish from serious infectious diseases, it is necessary to conduct disease monitoring on a regular basis. In this study, Hyporthodus septemfasciatus, Epinephelus moara, and the hybrid longtooth grouper (E. moara ♀×E. lanceolatus ♂) were collected once a month from fish farm of Garorim and Aquabiotech Co., Ltd for a total of six months, from July to December 2023. We investigated infections of five species of bacterial diseases, including Flavobacterium columnare, six species of viral diseases, including LCDV (lymphocystis disease virus), and parasitic pathogens in grouper farms. As the result, Vibrio vulnificus and V. harveyi were detected in H. septemfasciatus in August, in the case of viral diseases, NNV was detected in H. septemfasciatus from July to August using RT-PCR or PCR. Finally, In the case of parasitic diseases, Tricodina sp. was detected in E. moara and the hybrid longtooth grouper from August to December.