• 한국어병학회지
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• 제16권2호
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• pp.135-138
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• 2003

The research was carried out to know the occurrence trend of scuticociliatosis and mortality of fingerlings in flounder. The diseased fish were collected from on-land rearing farms lind hatcheries of flounder in Jeju Island from January 1991 to December 2001. Occurrence of scuticociliatosis was about 10% of total occurred diseases from 1991 to 1996, but increased to 34.5% in 2001. Although monthly occurrence of scuticociliatosis was not related to season from 1999 to 2001, the highest occurrence was revealed in July and August. Mixed infections of bacteria including Vibrio sp. Edwardsiella tarda, Streptococcus sp., and Flexibacter sp. with scuticociliates were observed. Among the bacteria, Vibrio sp. was the highest frequency(40.1%), and the lowest one(10.1%) was Streptococcus sp., Mortality of fingerlings by scuticociliates was different sharply according to size of fish. Mortality of infected fingerlings below 7 cm of total length was 53.8%, while that of normal fingerling above 7 cm of total length was 13.2%. When fish were grown above 25 cm, mass mortality by scuticociliates infection was decreased markedly.

• 한국어병학회지
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• 제25권2호
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• pp.117-121
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• 2012

The pathogenicity of viral hemorrhagic septicemia virus (VHSV) from olive flounder Paralichthys olivaceus was investigated with masu salmon Oncorhynchus masou fry. The cumulative mortality of fish challenged with FYeosu05 isolate at $10^{6.5}$ $TCID_{50}$/fish was 60%. No mortality was observed in fish challenged with the isolates at $10^{5.5}$ $TCID_{50}$/fish and in mock-challenged fish. The affected fish showed darkening of the body, expanded abdomen, pale gills and enlarged spleen. VHSV from $10^{6.3}$ to $10^{7.8}$ $TCID_{50}$/g-tissue was re-isolated from the dead fish. These results suggest that the VHSV from olive flounder is pathogenic to masu salmon fry, although with low virulence.

• 한국어병학회지
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• 제37권1호
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• pp.17-23
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• 2024

Spring viremia of carp virus (SVCV) poses a significant threat to numerous cyprinid fish species, particularly the common carp (Cyprinus carpio), often resulting in substantial mortalities. This study explores the potential use of a chimeric recombinant snakehead rhabdovirus carrying the SVCV G gene (rSHRV-Gsvcv) as a live vaccine against SVCV infection. Through virulence testing in zebrafish at different temperatures (15 ℃ and 20 ℃), no mortality was observed in groups infected with either rSHRV-wild or chimeric rSHRV-Gsvcv at both temperatures, whereas 100% mortality occurred in fish infected with wild-type SVCV. Subsequently, as no mortality was observed by rSHRV-Gsvcv, three independent experiments were conducted to determine the possible usage of chimeric rSHRV-Gsvcv as a vaccine candidate against SVCV infection. Fish were immunized with either rSHRV-Gsvcv or rSHRV-wild, and their survival rates against the SVCV challenge were compared with a control group injected with buffer alone at four weeks post-immunization. The results showed that chimeric rSHRV-Gsvcv induced significantly higher fish survival rates compared to rSHRV-wild and the control groups. These findings suggest that genetically engineered chimeric rSHRV-Gsvcv holds the potential for a prophylactic measure to protect fish against SVCV infection.

• Fisheries and Aquatic Sciences
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• 제13권1호
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• pp.79-83
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• 2010

Since 1998, a new viral disease with high mortality has been consistently recorded in Korea in cultured carp, Cyprinus carpio. In this study, we investigated an epizootic of the disease that caused high mortality rates in carp obtained from 11 farms in Korea between 1999 and 2007. Assessment of koi herpesvirus (KHV) levels in diseased carp was carried out to determine if this virus was the etiologic agent of disease in this instance. High mortality rates in carp were recorded mainly in the spring and autumn at water temperatures between $19^{\circ}C$ and $24^{\circ}C$. Diseased fish typically showed surface discoloration, with a thick opaque mucus covering the body and gills. Protozoan parasites and bacteria were recovered from 7/29 (24%) and 2/26 (8%) of fish, respectively. Evidence of viral infection was marked; cytopathic effects (CPEs), characterized by cell rounding and an extended cytoplasm in fathead minnow (FHM) cells, were detected in 40/41 fish (98%). A high mortality rate (80%) resulted when supernatants of cell cultures showing CPEs were applied to previously healthy fish. KHV was detected by polymerase chain reaction in 6/41 fish (15%), but was not detected in supernatants obtained from cell cultures showing CPEs. These results suggest that KHV may not be the etiologic agent of the high mortality occurring among cultured carp in Korea; therefore, some other-as yet unidentified-infective agent must be responsible.

• Animal cells and systems
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• 제7권4호
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• pp.345-348
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• 2003

The effects of acute acid stress on hatching success and hatching period of laboratory-reared hermaphroditic fish Rivulus marmoratus were examined. The effects of acute acid toxicity on mortality was also determined in three life stages of this fish. There was a significant negative effect of acid stress on hatching performance in the R. marmoratus embryos. The hatching success was only 5% at pH 3.5 compared to over 78% at pH higher than 4.0. The hatching period was also delayed by low pH treatments. The larval and juvenile stages were more sensitive to acid toxicity on mortality than the adult stage, but larvae and juveniles showed similar sensitivity. The 96-h LC50 value was pH 3.8 in larval and juvenile stages and pH 3.3 in adult stage.

• 한국임상수의학회지
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• 제26권2호
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• pp.150-154
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• 2009

최근 doctor fish(Gara rufa obtusa)를 이용한 Ichthyotherapy는 인간 피부질환의 대체 치료법으로 각광받고 있으며, 근래 doctor fish의 국내 증식 성공으로 인하여 이러한 추세는 증가되고 있다. 그러나 doctor fish의 질병과 생태에 대해서는 아직 연구가 미미한 실정이다. 본 보고는 국내에서 증식되던 doctor fish가 Citrobacter freundii에 감염되어 집단 폐사한 예로서, 병어에 대한 외부 및 내부 진단, 분리된 세균의 형태학적, 생화학적 동정을 통하여 C. freundii를 확정하였으며, 분리된 C. freundii에 대한 항생제 감수성 검사를 수행하였다. 또한 살아남은 병어에 대한 집단 치료를 시도하여 성공적인 치료 효과를 얻을 수 있었다.

• 한국어병학회지
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• 제21권1호
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• pp.35-43
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• 2008

남해안 일원의 양식 대상종인 참돔의 월동기간중의 폐사발생 원인구명을 위해 병리학적, 혈액생화학적 성상 및 장단기간 양식장의 수온조사를 종합비교하였다. 1. 월동 기간중에 폐사한 참돔의 병리학적조사결과, 육안적으로 녹간증, 장내 복수 증상을 나타내었으며, 경증의 아가미흡충 감염을 제외한 세균, 바이러스 질병은 확인하지 못하였다.2. 혈액생화학적 분석결과, 폐사시기에 혈중의 AST, ALT는 폐사시기에 급격히 높아졌으며, 단백질, 지방 성분값은 저하된 것으로 나타났다. 3. 실시간 양식어장 환경정보제공시스템의 수온 분석에 의하면, 참돔의 폐사가 가장 먼저 시작된 해역인 사량도 해역은 참돔의 저온 한계수온인 8℃ 이하의 수온이 42일간 지속된 것으로 나타나 저수온에 장기간 노출된 것으로 판단되었다. 4. 폐사가 많았던 사량도 양지와 미륵도 명지해역의 2003년에서 2006년까지 3년간 장기수온변화를 보면, 월동기간인 2005년 12월에서 2006년 2월까지의 수온이 2003, 2004년에 비해 낮은 수온 분포를 보였다.5. 참돔의 폐사발생해역은 비폐사해역에 비해 수심이 얕으며, 수층별 수온변화가 큰 것이 특징이었다.

• 한국어병학회지
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• 제23권3호
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• pp.335-342
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• 2010

2008년 3월 인도네시아로부터 수입된 paradise fish에서 대량폐사가 발생하여 병원체 검사를 실시한 결과, megalocytivirus 및 Mycobacterium sp.가 검출되었으며, CHSE-214세포에서 미동정 바이러스가 분리되었다. 본 연구에서는 미동정 바이러스의 특성을 조사하였으며, 또한 병원성 실험을 통해 paradise fish의 대량 폐사와의 연관성을 조사하였다. 분리 바이러스는 CHSE-214, BF-2, GF, SSN-1, FSP 및 FFN 세포에서 합포체의 세포변성효과를 나타내었고 IUdR 및 chloroform 처리에 감염성이 상실되지 않으며, 산 (pH 3), 알카리 (pH 11) 및 열 ($56^{\circ}C$, 30분)에 안정하였다. 핵산 분석 결과에서는 적어도 10개의 segment (0.7-3.6 kb)를 지닌 RNA 바이러스로 확인되었으며, 전자현미경 관찰 결과, 약 65 nm 크기로 인벨롭이 없으며 2중의 capsid를 지닌 바이러스가 세포질에서 관찰되었다. 이상의 결과는 Reoviridae family에 속하는 바이러스의 전형적인 특성과 일치하므로 paradise fish에서 분리된 바이러스는 reovirus로 확인되었다. Reovirus를 사용한 감염실험에서는 병원성이 나타나지 않아, reovirus는 paradise fish의 대량 폐사의 직접적인 원인이 아닐 것으로 사료되었다.

• 수산해양교육연구
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• 제28권1호
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• pp.1-13
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• 2016

Physiological response of fish and bivalve was estimated to identify the physiological changes of test species by lowering water temperature due to the abrupt stop of cooling water discharge from power plant. The experiment was conducted by two conditions; fall and winter by decreasing water temperature ($2^{\circ}C$/2 days) from $26^{\circ}C$ to $17^{\circ}C$ for fall scenario and from $15^{\circ}C$ to $9^{\circ}C$ for winter scenario, respectively. Test organisms were parrot fish (Oplegnathus fasciantus) and bivalve (Gomphina melanaegis), and end points were mortality for both species, hematocrit and cortisol for fish, and hemolymph and superoxide dismutase(SOD) for bivalve. 48/96hr mortality test revealed no mortality for fish and 47% mortality for bivalve at 96hr/$26^{\circ}C$ only. Significant increases of hematocrit and cortisol were found at fishes exposed to $26^{\circ}C$ (high temperature) and lower temperature ($9{\sim}13^{\circ}C$), respectively. Hemolymph and SOD for bivalve tended to decrease by lowering water temperature from 15 to $9^{\circ}C$ (winter scenario) and no changes from 26 to $17^{\circ}C$ (fall scenario). Fall scenario (from 15 to $9^{\circ}C$) showed more significant changes of physiological response than winter cases (26 to $17^{\circ}C$).

• 한국환경복원기술학회지
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• 제13권1호
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• pp.57-68
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• 2010

The purpose of this study is to analyze the characteristics of environment-friendliness of waterproof materials based on comprehensive experiments on waterproofness in terms of coefficients of permeability, harmfulness of waterproof materials and fish toxicity of Oryzias latipes mortality to verify eco-toxicity of each method of construction and waterproof material, which are to be applied by taking eco-toxicity into account when building ecological flows in upper areas on natural and artificial grounds. As a result, the following conclusions have been reached in this study: 1. In regard of the harmfulness analyzed, each material showed a different result of analytical value in each lab tank. Compared to input water, pH, COD, SS, T-P, and T-N values increased a little, but DO value decreased. The value of turbidity analyzed independent of the water quality standard of aquatic ecosystem set forth by the Ministry of Environment increased a little compared to the value in input water. 2. In the experiment of fish toxicity, compacted quicklime, cement fluid waterproof material, cement mortar waterproof material and bentonite powder were found to have 100% of fish mortality, respectively, and membrane waterproof material showed 83.3% of mortality, indicating strong fish toxicity. Improved asphalt sheet (63.3%) and synthetic rubber sheet (53.3%) were analyzed to have medium fish toxicity, while bentonite sheet (6.7%), Hwang-toh (6.7%) and clay (3.3%) showed relatively lower mortality and fish toxicity. 3. Regarding the analysis on waterproofness in terms of the coefficient of permeability of each waterproof material, improved asphalt sheet, synthetic rubber sheet, membrane waterproof material, cement fluid and mortar waterproof material and bentonite sheet were found impervious in case no leakage takes place in construction. Bentonite powder was found practically impervious based on the analytical results from the experiment done in compliance with weight ratios. So were the clay and Hwang-toh from the experimental results. To sum up such results as found in the experiment mentioned so far, the values of harmfulness and waterproofness analyzed were different in each lab tank, but there was absolutely little correlation with the mortality gained from the experiment on fish toxicity. In the experiment of fish toxicity, environment-friendly waterproof materials were analyzed, and it was found that clay, Hwang-toh and bentonite sheet are highly environment-friendly. In contrast, synthetic rubber and improved asphalt sheets were found to have medium-level environment-friendliness. Also, membrane water-proof materials, compacted quicklime, cement fluid and mortar waterproof material and bentonite powder were analyzed to have low environment-friendliness.