• Journal of fish pathology
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• v.32 no.2
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• pp.123-127
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• 2019

In this study, white spots appearing in carapace of imported white leg shrimp Litopenaeus vannamei were observed by macroscopic and microscopic examination. White spots due to white spot disease showed two types, white spots with a regular circular shape ranging from 0.4 mm to 1.7 mm and white spots with an irregular shape ranging from 0.05 mm to 2 mm. White spots due to other causes showed four types that appeared as crystalized materials in range of 100 ㎛ around the tegumental gland, as polygonal inorganic deposits ranging from 58 ㎛ to 188 ㎛, as Linear inorganic deposits ranging from 0.8 mm to 9 mm, as brownish spots ranging from 0.1 mm to 0.4 mm, and brownish spots containing melanin ranging from 0.1 mm to 2 mm. As a result, white spots occurred in imported white leg shrimp Litopenaeus vannamei were divide two type, due to white spot disease or other causes, for quarantine works.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.511-515
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• 2007

White-spot syndrome virus (WSSV) is a devastating, infectious virus affecting shrimp. Although sensitive techniques involving PCR have been developed to assist farmers in screening shrimp (brood stock) for WSSV prior to stocking ponds, such practices have not yet been applied in Korea. Despite the rationality of implementing screening, there has been some doubt as to whether the stocking of WSSV-PCR-negative fly epidemiologically decreases white-spot disease outbreaks. Here, we report a retrospective analysis of data from shrimp farms in the western coast of Korea where WSSV-PCR-negative brood stocks were used to stock rearing ponds. A total of 366 shrimp from Heuksan Island were sampled for WSSV with PCR. Of the tested shrimp, 7.2% (28 brood stocks) were identified as WSSV positive; only WSSV-PCR-negative shrimp were used for brood stocks. Total unit production (final shrimp production/ the area of the ponds) was higher, at 1.96, in ponds where WSSV-PCR-negative shrimp were used, as compared with 1.02 in other ponds in Korea in 2004. This retrospective analysis of WSSV in Korea may be useful to the shrimp aquaculture industry, suggesting a testable hypothesis that may contribute to the eventual control of WSSV outbreaks.

• Journal of fish pathology
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• v.10 no.2
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• pp.87-95
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• 1997

Baculovirus associated with white spot syndrome (WSBV) is the causative agent of a disease with high mortalities and causes severe damage to shrimp cultures. In this study, we analyzed a recombinant clone (E3) obtained from a viral genomic library to characterize the causative agent in diseased shrimp Penaeus chinensis with white spot syndrome. According to the analysis of nucleotide sequence of E3, this clone did not showed considerable sequence homology with those of other known viruses, including baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV), indicating that WSBV is a novel virus causing a serious disease in P. chinensis. Based on the sequence of E3 clone, a pair of PCR primers was designed. After 30 cycles of amplification, a specific product of the expected size was detected only if the total nucleic acids extracted from the diseased shrimp was used as a template DNA, suggesting that this method can be used to diagnose the virus infection in diseased shrimp.

• Proceedings of the Korean Aquaculture Society Conference
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• 2001.12a
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• pp.227.2-228
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• 2001

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.394-398
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• 2001

Because of the great concern over the possibility of contamination from the rod-shaped nuclear virus (PRDV) from Japan and white spot virus (WSSV) from Taiwan, most eggs used in Korean shrimp farms are currently obtained from local broodstock. In addition, the screening of imported broodstock for any viral presence at the National Fisheries Research and Development Institute is also mandatory. Nonetheless, massive mortality from white spot syndrome continues in Korea. In the present study, we present an improved PCR method to use tissue-extracted DNA instead of viral DNA extracted from a purified virus based on a sucrose density gradient, and produced results within 8 h. In 1998, this modified PCR method was able to detect that diseased Penaeus japonicus were infected within 8 h. In 1998, this modified PCR method was able to detect that diseased Penaeus japonicus were infected only with PRDV, while Fenneropenaeus chinensis were infected with both PRDV and WSSV. In 1999, PRDV and WSSV were detected in F. chinensis with signs of infection, but not with WSSV alone.

• BMB Reports
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• v.37 no.6
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• pp.726-734
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• 2004

White spot disease (WSD) is caused by the white spot syndrome virus (WSSV), which results in devastating losses to the shrimp farming industry around the world. However, the mechanism of virus entry and spread into the shrimp cells is unknown. A binding assay in vitro demonstrated VP28-EGFP (envelope protein VP28 fused with enhanced green fluorescence protein) binding to shrimp cells. This provides direct evidence that VP28-EGFP can bind to shrimp cells at pH 6.0 within 0.5 h. However, the protein was observed to enter the cytoplasm 3 h post-adsorption. Meanwhile, the plaque inhibition test showed that the polyclonal antibody against VP28 (a major envelope protein of WSSV) could neutralize the WSSV and block an infection with the virus. The result of competition ELISA further confirmed that the envelope protein VP28 could compete with WSSV to bind to shrimp cells. Overall, VP28 of the WSSV can bind to shrimp cells as an attachment protein, and can help the virus enter the cytoplasm.

• Journal of Veterinary Science
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• v.21 no.2
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• pp.31.1-31.5
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• 2020

In this study, whiteleg shrimp (Penaeus vannamei) imported from Vietnam were collected from South Korean markets, and examined for 2 viruses: infectious hypodermal and hematopoietic necrosis virus (IHHNV, recently classified as decapod penstyldensovirus-1), and white spot syndrome virus (WSSV). Among 58 samples, we detected IHHNV in 23 samples and WSSV in 2 samples, using polymerase chain reaction and sequencing analyses. This is the first report of IHHNV and WSSV detection in imported shrimp, suggesting that greater awareness and stricter quarantine policies regarding viruses infecting shrimp imported to South Korea are required.

• Journal of fish pathology
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• v.35 no.1
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• pp.129-133
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• 2022

The full genome sequence of a Korean white spot syndrome virus (WSSV, isolate: WSSV-GoC18) is presented here. We obtained a total of 12,320,554 reads with 291,172 bases, 170 gene, and 170 coding DNA sequence, which were assembled in 1 contig. Phylogenetic analysis revealed that the WSSV-GoC18 was closely related to Chinese isolate (WSSV-PC) and distinctly different with previously reported a Korean isolate (WSSV K-LV1). The complete genome sequence of WSSV isolates will be of great help in molecular epidemiological studies, contributing to molecular diagnosis and disease prevention in shrimp aquaculture.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.519-520
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• 2001

1993년 초여름부터 발생한 양식대하의 WSBV에 의한 대량 폐사가 1996년에는 폐사율이 거의 75％에 이를 정도로 피해가 많이 발생하였다(허 등, 1998). WSBV에 감염된 새우는 두흉갑과 체표에 흰반점 증상이 나타나므로 병명을 일반적으로 White spot syndrome disease(WSSD)라고 하고 원인 바이러스를 WSBV라 일반적으로 명명하고 있고 이와 같은 증상으로 인한 새우의 대량 폐사는 아시아 전역에서 일어나고 있다(Chou 등, 1995; Inouye 등, 1996). (중략)

• Journal of Aquaculture
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• v.15 no.1
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• pp.7-13
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• 2002

Since 1993, the White Spot Syndrome Virus (WSSV) disease occurred in China among cultured shrimps resulting in mass mortality. Epizootiological surveys undertaken during the outbreak period of 1993-1994 indicated that all stages of Penaeus chinensis, P. japonicus and P. monodon were infected. Consequent to the transport of contaminated shrimp seedlings and seawater, the disease spread all over the farms of China. The disease was more rapidly transmitted at temperatures above $25^{\circ}C$. Challenge experiments showed the causative agent was highly virulent. White spots appeared on the carapace of both span-taneous and experimentally infected shrimps. Moribund shrimps contained turbid hemolymph, hypertrophied Iymphoid organ and a necrotic mid-gut gland. Electron microscopy showed the presence of viral particles in the gills, stomach, lymphoid organ, and epidermal tissue of the infected shrimp. The visions were slightly ovoid with an envelope and averaged 350 $\times$ 150 nm; nucleocapsids measured 375 $\times$ 157 nm. With discontinuous sucrose gradient of 35, 50 and 60% (w/v), the virus was separated from hemolymph of the infected shrimp. The estimated molecular weight of genomic DNA was 237 Kb with EcoR I, 247 Kb with Hind III and 241kb with Pst I. A total of 9 hybridoma colones secreting monoclonal antibodies (MAbs) were produced from mouse myeloma and spleen cells immunized with WSSV. The immunofluorescence assay of gill tissue showed that the MAbs reacted with diseased but not with healthy shrimp. The MAbs belonged to IgGl, IgG2b subclass and IgM class, all with kappa light Immune-electron-microscopy with colloidal gold marker showed the presence of 5 MAbs epitopes on the envelope and one on the capsid of the virus. Baculoviral mid-gut gland necrosis showed the specificity of the MAbs produced. For diagnosis 5 different methods were selected. Using Kimura primers for PCR, or MAbs for immunoblot, ELISA or FAT method, in situ hybridization was carried out to show the gene. All these methods detected WSSV in the organ samples of the diseased shrimp but not in healthy one.