• 한국어류학회지
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• 제27권3호
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• pp.183-188
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• 2015

본 연구에서는 무지개송어의 해수면 양식장으로의 이동에 따라 나타날 수 있는 어류 병원성 바이러스의 영향을 알아보기 위해, 담수 무지개송어 유래 병원체인 infectious hematopoietic necrosis virus (IHNV)와 infectious pancreatic necrosis virus (IPNV)를 사용하여 주요 해산 양식 어종인 넙치, 조피볼락, 돌돔, 참돔 및 능성어에 주사한 후 병원성 및 감염 여부를 조사하였으며, 또한 해산 양식 어종 유래 병원체인 marine birnavirus (MABV), hirame rhabdovirus (HIRRV) 및 nervous necrosis virus (NNV)를 사용하여 무지개송어에 대한 병원성 및 감염 여부를 조사하였다. IHNV와 IPNV는 주요 해산 양식 어종에 감염되는 것으로 확인되었으며, 또한 무지개송어는 해산 유래 위해 병원체인 MABV와 NNV에 감염되거나 HIRRV에 의해 폐사되는 것으로 확인되었다. 이상의 연구 결과, 해수사육 무지개송어는 어류 병원성 바이러스들에 의해 영향 받을 수 있을 것으로 사료되었다.

• 한국어병학회지
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• 제33권1호
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• pp.71-75
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• 2020

A survey was conducted to investigate viral infections in 184 whiteleg shrimp (Litopenaeus vannamei) collected from nine farms and one wholesale fish vendor during 2018 and 2019. Gill and abdominal muscle of shrimp were tested for the presence of five viruses, viz. infectious hypodermal and haematopoietic necrosis virus, taura syndrome virus, infectious myonecrosis virus, yellow head virus genotype 1, and covert mortality nodavirus by reverse transcription-polymerase chain reaction (RT-PCR) and PCR. These viruses were not detected in any of 184 samples, screened under the study.

• 한국어병학회지
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• 제21권3호
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• pp.181-188
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• 2008

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to detect and identify four fish viruses, fish iridovirus, viral hemorrhagic septicaemia virus (VHSV), viral nervous necrosis virus (VNNV), hirame rhabdovirus (HRV). Four viruses were detected by PCR with each specific primers. Identification of iridovirus was achieved by digesting the PCR amplified fragment with a restriction enzyme ApaⅠ. It was possible to distinguish positive from false positive PCR amplicons of VHSV by RFLP of PstⅠ or HindⅢ restriction enzymes. VNNV was identified using RFLP of BamHⅠrestriction enzyme and HRV was identified by XbaⅠ restriction enzyme. This approach can be used for more rapid, simple and specific diagnosis of fish viral diseases.

• 한국수산과학회지
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• 제35권3호
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• pp.237-241
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• 2002

This study was performed both to explore the host of nervous necrosis virus (NNV) between mariculturing fish species and to examine the phylogenic position of the NNV in Korea. NNV was confirmed on the basis of histopathological and molecular biological examination, then VNN infection was Preyed from either moribund or dead fishes including red drum, Sciaenops ocellatus; oblong rock fish, Sebastes oblongus and flounder, Paralichthys olivaceus. As a result of sequencing for a part of ms, virus from red drum was showed $98\%, $97\%, $86\% and $74\% homology with oblong rock fish, grouper, Japanese flounder and striped jack, respectively. On the other hand, NNV from oblong rock fish was demonstrated $96\%, $85\% and $72\% homology with grouper, Japanese flounder and striped jack, respectively. NNV from red drum and oblong rock fish was exhibited phylogenically distant from the representative NNV, SJNNV originated from striped jack. On the contrary, the viruses appeared to be similar species with Taiwan NNV isolated from culturing grouper.

• 한국어병학회지
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• 제30권2호
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• pp.135-148
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• 2017

Pathogen introductions associated with aquatic invasive species threaten ecosystems and biodiversity worldwide. Bigheaded carps (BHC), including Silver Carp Hypophthalmichthys molitrix, Bighead Carp H. nobilis, and their hybrids, are prolific, invasive pests in central US rivers. However, little is known about pathogen effects on invading BHC or how BHC affect the disease risk profile for native fishes in receiving ecosystems. We therefore conducted, from May 2013-December 2014, a systematic pathogen survey for BHC and native fishes in the Wabash River watershed, Indiana, USA. We found Pseudomonas fluorescens, P. putida, and Salmonella enterica DNA in BHC as well as native fishes, although none of these bacteria were exclusively present in BHC. DNA from other bacterial taxa was detected only in native fishes and Common Carp Cyprinus carpio. No gastrointestinal helminths were detected in BHC, although they were common in most native fishes examined. We also conducted in vitro studies on BHC tissues (skin, gill, fin, and fry) and found high sensitivity to Largemouth Bass virus, viral hemorrhagic septicemia virus, and infectious pancreatic necrosis virus. We conclude that BHC are not heavily burdened by bacteria, viruses and parasites in the invaded study ecosystems, although they do harbor native bacteria and show potential for high sensitivity to endemic viruses.

• 한국어병학회지
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• 제35권2호
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• pp.157-165
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• 2022

Single-cycle viruses generated by reverse genetic technology are replication-incompetent viruses due to the elimination of gene(s) essential for viral replication, which provides a way to overcome the safety problem in attenuated viruses. Infectious hematopoietic necrosis virus (IHNV) is a major pathogen causing severe damage in cultured salmonid species. In the present study, we generated a single-cycle IHNV lacking the transmembrane and cytoplasmic domain in the G gene (rIHNV-GΔTM) and evaluated the prophylactic potential of rIHNV-GΔTM in rainbow trout (Oncorhynchus mykiss). To produce rIHNV-GΔTM, IHNV G protein-expressing Epithelioma papulosum cyprini (EPC) cells were established. However, as the efficiency of rIHNV-GΔTM production in EPC cell clones was not high, fish were immunized with a low-tittered single-cycle virus (1.5 × 10² PFU/fish). Despite the low dose, the single-cycle IHNV induced significant protection in rainbow trout against IHNV infection, suggesting high immunogenicity of rIHNV-GΔTM. No significant difference in serum ELISA titers against IHNV between the rIHNV-GΔTM immunized group and the control group suggests that the immunized dose of rIHNV-GΔTM might be too low to induce significant humoral adaptive immune responses in rainbow trout. The involvement of adaptive cellular immunity or innate immunity in the present significantly higher protection by the immunization with rIHNV-GΔTM should be further investigated to know the protection mechanism.

• 한국어병학회지
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• 제28권2호
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• pp.113-116
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• 2015

A $0.45-{\mu}m$ membrane filter is generally used to remove bacterial contamination during virus extraction from fish samples. However, the number of fish viruses is drastically reduced after filtration with a $0.45{\mu}m$ filter. In this study, we investigated the effect of filters on virus infectivity titer and the change in virus titer and bacterial number following different centrifugation conditions to determine a suitable procedure for virus extraction from fish samples. $10^{4.05}$ and $10^{5.05}TCID_{50}/ml$ of infectious hematopoietic necrosis virus (IHNV) and $10^{4.05}$ and $10^{4.55}TCID_{50}/ml$ of Oncorhynchus masou virus (OMV) were not detectable after filtration with two types of $0.45-{\mu}m$ filters, except the IHNV titer was reduced by about 10 fold after filter use (company A). No significant difference was found in the virus titer following centrifugation at $880{\times}g$ (30 min) or $3,500{\times}g$ (30 min), whereas IHNV and OMV titers were reduced by about 10 and 10-1000 fold by centrifugation at $14,000{\times}g$ (30 min) and $14,000{\times}g$ (10 and 30 min), respectively. A total of 97.7-99.9% Escherichia coli were eliminated by centrifugation at $880 {\times}g$ (30 min) and $3,500{\times}g$ (30 min). These results show that fish viruses were affected by filtering, even though the effect differed by virus species and filter type. Therefore, centrifugation at $3,500{\times}g$ (30 min) and use of medium with antibiotics may be useful for virus extraction along with a reduction in bacteria.

• 한국어병학회지
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• 제31권2호
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• pp.71-79
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• 2018

2015년 2월부터 2018년 8월까지 총 1,253 마리의 자연산 명태 (Gadus chalcogrammus)를 강원도 고성 아야진항 근해에서 정치망을 사용하여 포획한 후, 바이러스 (viral hemorrhagic septicemia virus, VHSV; nervous necrosis virus, NNV; marine birnavirus, MABV) 모니터링을 RT-PCR법으로 수행하였다. One-step PCR법으로 비장시료 및 뇌시료에서는 대상 바이러스가 모두 검출되지 않았으며, 일부 시료를 two-step PCR법으로 검사한 결과 VHSV는 19.7% (36/183)의 비장시료에서 검출되었다. 또한, NNV는 4.4% (8/183)의 비장시료, 1.2% (3/259)의 뇌시료에서 검출되었다. 검출된 바이러스의 계통분석 결과, 기존의 국내에서 분리되는 바이러스의 유전형에 각각 속하는 것으로 나타났다 (Genotype IVa, RGNNV genotype). 바이러스의 분리를 시도하지 않아 검출된 바이러스의 활성은 알 수 없지만, 모든 양성 시료가 two-step PCR법으로 검출되었으므로 매우 낮을 것으로 추측된다.

• 한국어병학회지
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• 제26권3호
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• pp.283-287
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• 2013

본 연구에서는 어류병원바이러스 (infectious pancreatic necrosis virus (IPNV), viral hemorrhagic septicemia virus (VHSV), hirame rhabdovirus (HIRRV), infectious hematopoietic necrosis virus (IHNV), lymphocystis disease virus (LCDV))를 대상으로 바다 송사리 Oryzias dancena의 감수성을 조사하였다. 감염실험 결과, IPNV (실험조건: $15^{\circ}C$ 해수), VHSV ($15^{\circ}C$ 해수) 및 HIRRV ($15^{\circ}C$ 담수)에 침지된 송사리는 각각 30%, 40%, 60%의 누적폐사율이 관찰되었다. 이에 반해 IPNV ($15^{\circ}C$ 담수, $18^{\circ}C$ 해수 및 담수), VHSV ($15^{\circ}C$ 담수, $18^{\circ}C$ 해수 및 담수), HIRRV ($15^{\circ}C$ 해수), IHNV ($15^{\circ}C$ 해수 및 담수), LCDV ($15^{\circ}C$와 $18^{\circ}C$ 해수 및 담수) 침지 실험구 및 대조구에서는 10% 이하의 누적 폐사율이 확인되었다. 생존어와 폐사어를 대상으로 한 바이러스 분리 결과에서는 IPNV, VHSV 및 HIRRV에서 폐사된 개체로부터 바이러스가 분리되었으며, 또한 IPNV와 HIRRV에서 생존한 개체로부터도 바이러스가 분리되었다. 이상의 결과로 바다 송사리는 IPNV, VHSV 및 HIRRV에 감수성이 있음이 확인되었다.

• 한국수산과학회지
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• 제46권1호
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• pp.46-52
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• 2013

After an outbreak of viral disease in an aquafarm, release of virus (es) from infected fish into environmental seawater has been suspected. In the present study, we utilized a negatively charged membrane (HA type) as an efficient method for concentration and detection of fish pathogenic viruses, specifically, megalocytivirus and viral hemorrhagic septicemia virus (VHSV) present in field-collected seawater samples or inoculated into seawater artificially. Positively charged viruses adsorbed onto the negatively charged membrane and were eluted with 1 mM NaOH (pH 10.5) following rinsing with 0.5 mM $H_2SO_4$ (pH 3.0). Megalocytivirus and VHSV particles isolated using anegatively charged HA membrane from seawater inoculated with each virus at a concentration of 10 viral particles/mL were of sufficient quantity to show positive results in atwo-step PCR (or RT two-step PCR); however, despite it being negatively charged, a cellulose acetate (CA) membraneshowed negative results. In quantitative PCR, the detection limits of the HA membrane for megalocytivirus and VHSV in seawater were 1.20E+00 viral particles/mL and 1.22E+01 viralparticles/mL, respectively. The calculated mean recovery yields from 1 L seawater spiked with known concentrations of megalocytivirus and VHSV particles were 28.11% and 23.00%, respectively. The concentrate of a 1-L sample of culturing seawater from the aquatank of flounder suffering from VHSV showed clear positive results in PCR when isolated with an HA, but not a CA, membrane. Thus, viral isolation using an HA membrane is a practical and reliable method for detection of fish pathogenic viruses in seawater.