• 한국수산과학회지
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• 제47권3호
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• pp.241-246
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• 2014

Viruses in the genus Megalocytivirus have been subdivided into four subgroups. Among these subgroups 2 and 4, represented by the red sea bream iridovirus (RBIV) and the olive flounder iridovirus (FLIV), respectively, are non-exotic. subgroups 1 and 3, represented by the red sea bream iridovirus (RSIV) and the infectious spleen and kidney necrosis virus (ISKNV), respectively, have not been detected in Korea and are known as exotic. Shellfish are filter-feeders, and can thus filter and accumulate Megalocytivirus in their digestive glands, allowing us to track viral contamination in surrounding aquatic environment. In this study, we developed a high-resolution melting (HRM) analysis to differentiate among subgroups of Megalocytivirus accumulated in shellfish, and confirmed the convenience and efficiency of this method. More than two subgroups of Megalocytivirus were found in the digestive gland of a single shellfish. We classified all Megalocytivirus viruses from shellfish in Korea into subgroups 2 and 4, although proportions of subgroups were different among regions. Compared to nucleotide sequencing analysis, HRM analysis is a simple and rapid method for differentiating of Megalocytivirus subgroups.

• 대한수의학회지
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• 제33권1호
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• pp.125-129
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• 1993

An acute fatal infectious disease in rabbits has been outbroken in Korea since 1985. This disease has been characterized as an acute hepatitis caused by viruses. However, viral pathogenesis in rabbit viral hepatitis leading to sudden death remain unclear. This report dealt with the electron microscopic findings on the spleen of experimentally infected rabbits, because spleen is one of the affected organs which have high titer of virus by a haemagglutination test. A typical crystalline array of virus was not found in the splenic cells of infected rabbits with acute hepatitis. Virus-like particles were seen within the phagosome of macrophages of the spleen. Ultrastructural changes in the spleen were severe with the lapse of time after inoculation. From these results, virus-like particles in the spleen were supposed to be phagocytosed by macrophage during viremia, while active replication of virus occurred in the liver. It was concluded that sudden death in this viral disease was caused by hepatic coma and/or circulatory disturbance.

• 식품과학과 산업
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• 제55권3호
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• pp.244-263
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• 2022

Coronavirus, known as one of the causes of colds including mild upper respiratory tract disease in humans, has mutated into the infectious severe disease, COVID-19 through SARS and MERS. The mortality and symptoms of COVID-19 are related to the ability to regulate innate immunity, which acts as the first barrier against microorganisms and viruses. During the COVID-19 pandemic, the demand for food that helps to strengthen immunity is rapidly increasing. Functional foods promote general health and alleviate the risk of disease symptoms by activating multiple biological functions. A recent, there is an interest in discovering functional substances that can induce enhancement of immunity and prevent viral infection as well as relieve disease symptoms. Therefore, this article focus to understand the concept of immune response and highlights the recent status of functional foods and research trends that can help prevent and treat viral infections by inducing the enhancement of immune function.

• 한국동물위생학회지
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• 제35권1호
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• pp.9-17
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• 2012

The objective of the present study was to isolate and identify infectious bursal disease viruses (IBDVs) from broiler and layer chickens of outbreaks of infectious bursal disease (IBD) in three districts of Bangladesh. A total of 70 bursal samples were collected from dead broiler (n=40) and layer (n=30) chickens showing specific lesions of IBD from seven commercial poultry farms of three different districts (Mymensingh, Chittagong and Tangail) of Bangladesh during the year 2007. Five representative bursal samples from each farm were used for the isolation of IBDVs using 9-day-old embryonated eggs of seronegative flock of layer birds and for identification the samples were subjected to agar gel immunodiffusion test (AGIDT), immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Out of 35 bursal samples, IBDVs were successfully isolated from 28 (80%) samples. By AGIDT, 32 (91.4%) samples were found positive for IBDV antigen. Results of AGIDT clearly indicated that IBDVs detected in 29 bursal samples of six affected farms were identical to each other but not to IBDVs present in the remaining three samples of another farm. Indirect immunoperoxidase staining of the bursal sections revealed the presence of IBDV antigen in 32 (91.4%) samples and the IBDV antigen was detected mainly in the cortex of the lymphoid follicles of the bursal tissues. In histopathology, cell depletion, atrophy and necrosis were observed in many bursal follicles with severe edema of interfollicular septa. Of the 35 bursal samples, 34 (97.1%) samples generated 254 bp product by RT-PCR. In conclusion, the results of virus isolation and identification by AGIDT, IHC and the analysis of viral genome by RT-PCR confirmed the outbreaks of acute IBD in commercial poultry of Bangladesh. Moreover, histopathological findings and results of AGIDT gave a clear indication that the isolates from six outbreaks were different from classical strain and it seems to be of very virulent strain. On the other hand, the isolates from the other outbreak were similar to the classical strain.

• 대한치과의사협회지
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• 제58권10호
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• pp.615-626
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• 2020

The outbreak of COVID-19, caused by SARS-CoV-2 infection, has spread worldwide and resulted in a pandemic for health systems. The disease is transmitted via respiration as droplets or aerosol. Due to the nature of dental treatment, aerosols, including body fluid, blood, and saliva, are frequently produced in dental hospitals. The present study investigated the potential risk of nosocomial infection of COVID-19 in dental hospitals to provide recommendations in clinical situations. The Seoul National University Dental Hospital in Korea established a countermeasure to cope with the clinical situation based on The Guidelines of Korean Centers for Disease Control & Prevention (KCDC) for dental practitioners and the available literature. Notably, numerous considerations for patient reservation and schedule management are required for space separation in the hospital, including infection control. Experiences in dental hospitals in Korea would be referable for other dental hospitals facing this infectious respiratory disease.

• 한국동물위생학회지
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• 제34권2호
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• pp.95-102
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• 2011

Foot-and-mouth disease (FMD) is one of the most infectious diseases affecting cloven-hoofed animals including cattle, sheep, goats, and pigs. Seven serotypes of foot-and-mouth disease virus with multiple subtypes within each serotype have been identified until now. In particular, it has been demonstrated that the outbreak of the serotype Asia1 reported from China, Mongolia and North Korea since 2005 is mostly classified into genetic group V. Though it has been recommended that Asia1 Shamir strain can be used as a high priority vaccine by World References Laboratory for FMD, the complete nucleotide sequences of the strain has not yet been determined. In this study, to be prepared for Asia1 type viruses that may be brought into Korea, the complete genome sequence of this vaccine strain Asia1 Shamir including its 5' and 3' non-coding region was identified.

• 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.

• Journal of Microbiology and Biotechnology
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• 제31권4호
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• pp.529-539
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• 2021

The beet armyworm, Spodoptera exigua, is a serious insect pest infesting various vegetable crops. Two infectious insect viruses, baculovirus and iflavirus, are known to induce epizootics in S. exigua populations. Indeed, some laboratory colonies have appeared to be covertly infected by these viruses. Diagnostic PCR tests detected two different viruses: Spodoptera exigua multiple nucleopolyhedrosis virus (SeMNPV) and iflaviruses (SeIfV1 and SeIfV2). Viral extract from dead larvae of S. exigua could infect Sf9 cells and produce occlusion bodies (OBs). Feeding OBs to asymptomatic larvae of S. exigua caused significant viral disease. Interestingly, both SeIfV1 and SeIfV2 increased their titers at late larval stages. Sterilization of laid eggs with 1% sodium hypochloride significantly reduced SeMNPV titers and increased larval survival rate. Double-stranded RNA (dsRNA) specific to SeIfV1 or SeIfV2 significantly reduced viral titers and increased larval survival rate. To continuously feed dsRNA, a recombinant Escherichia coli HT115 expressing SeIfV1-dsRNA was constructed with an L4440 expression vector. Adding this recombinant E. coli to the artificial diet significantly reduced the SeIfV1 titer and increased larval survival. These results indicate that laboratory colony collapse of S. exigua is induced by multiple viral infections. In addition, either suppression of SeMNPV or SeIfV infection significantly increased larval survival, suggesting a cooperative pathogenicity between baculovirus and iflavirus against S. exigua.

• 한국가금학회지
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• 제38권3호
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• pp.181-189
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• 2011

새 깔짚을 사용하는 16개 농가와 깔짚을 교체하지 않는 15개 농가를 대상으로 2009년 7월부터 11월까지 5개월에 걸쳐 농가당 2회 입식 기준으로 병아리 입식 전과 출하 전 깔짚을 수거하여 주요 바이러스 병원체의 오염 실태를 조사하고, 생산성을 분석하였다. 그 결과, 조사 기간 동안 깔짚을 교체해 주는 농가의 75%(12/16농가)에서, 깔짚을 재사용하는 농가의 73%(11/15)에서 37주의 바이러스가 분리되었다. 바이러스분리 시기별로보면병아리 입식 직전계사에서3주, 육계 출하 직전 계사에서 34주가 분리되었다. 깔짚 형태로 보면 새 깔짚을 사용하는 계사에서 17주, 깔짚을 재사용하는 계사에서 20주가 분리되어 계사 내 바이러스 병원체 오염정도는 깔짚 교체여부와 크게 관련성이 없는 것으로 나타났다. 분리된 바이러스 37주는 병원체별로 보면 IBV 14주, IBDV 2주, FAdV 9주 그리고 CIAV 12주였다. 이 중 IBDV 1주와 CIAV 2주는 입식 직전 계사에서 분리되었다. 본 연구에서 조사한 31개 농장 62개 계군의 생산지수를 조사한 결과, 깔짚 교체 농가와 재활용 농가 간 생산성은 유의성이 있는 차이가 나타나지 않았다.