• Korean Journal of Pharmacognosy
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• v.29 no.4
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• pp.277-282
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• 1998

In order to search for anti-Herpes simplex virus type 1(HSV-1) agents, we screened 80 specimens of Korean traditional medicine by SRB assay. The methanol extracts of Thujae orientalis Semen (Cupressaceae) showed strong anti-HSV activity among samples tested. From the butanol fraction of Thujae orientalis Semen anti-HSV-1 agent was isolated by chromatographic separation using Amberlite XAD-4 and Sephadex LH-20. The structure was elucidated by spectroscopic methods, and was identified as ${\beta}-sitosterol$ (compound I). Compound I exhibited anti-HSV-1 activity with $EC_{50}$ of 0.6 mg/ml and $CC_{50}$ of 5.99 mg/ml, respectively.

• Korean Journal Plant Pathology
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• v.14 no.1
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• pp.68-73
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• 1998

Barley mild mosaic virus (BaMMV-Kor) was isolated from the southern part of Korea, and by mechanical inoculation onto barley cultivars, purification and production of antibody. BaMMV-Kor purified form infected plants were filamentous particle, with 13 nm in diameter and 250∼300 nm and 500∼650 nm in length. Antibody of BaMMV-Kor was made by injecting the purified virus to the muscle of a rabbit. In gel-diffusion test, antibody to BaMMV-Kor created spur with BaMMV-Kal and BaMMV-M, but did not make spur with BaMMV-Kor infected New Golden, Ishukushirazu, Joshushiro Hadaka and Misato Golden, but did not infect Kashimamugi, Chikurin Ibaraki 1 and Mokusekko 3. In Korean barley cultivars, BaMMV-Kor infected most of the covered barley cultivars, but did not infect Saeolbori. It also infected naked barley cultivars except Chalbori and Hinssalbori. And all the beer barley cultivars were infected by BaMMV-Kor. BaMMV-Kor had two RNAs, RNA 1 (7.5 Kb) and RNA 2 (3.5 Kb), and coat protein (33 KDa).

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.471-477
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• 1991

Attempts to isolate chicken anemia agent (CAA) were made by inoculating tissue homogenates into MDCC-MSBl or LSCC-1104B1 cell lines and passaging the cells serially. CAA was isolated from the liver and thymus of 11 weeks old layer chickens and from the liver of 10 weeks old broiler breeder chickens. The layer flock experienced approximately 45% mortality during 9 to 14 week of age from gangrenous dermatitis and lymphoid organs of affected chickens were severely atrophied. The broiler breeder flock experienced approximately 7% mortality during 7 to 9 weeks of age and affected birds showed lesions of colibacillosis, staphylococcal arthritis, and coccidiosis together with atrophied lymphoid organs. The isolated viruses were identified as CAA by the indirect fluorescent antibody test and virus neutralization test using CAA immune sera including one to Gifu-1 strain of CAA. The CAA isolate 89-69, when inoculated into susceptible 1 day old SPF chicks, induced anemia 14 to 16 days after inoculation. It did not induce any cytopathic effects in chicken embryo liver and chicken embryo fibroblast cell cultures. Infectivity of the isolate was not affected by the treatment of chloroform or heat ($70^{\circ}C$ for 15 minutes).

• Korean Journal of Veterinary Service
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• v.41 no.1
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• pp.51-55
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• 2018

Herein, we report a case of badgers showing high morbidity and mortality rate due to the mixed infection of canine distemper virus (CDV) and Streptococcus canis (S. canis) in a farm where wild animal, badger, is being reared for herbal medicine. During the period of about one month, 120 out of 320 badgers showed severe respiratory symptoms and died, and 3 bodies were submitted to the Animal and Plant Quarantine Agency for disease diagnosis. The lung with the most severe necropsy findings failed to collapse and showed dark reddening and had yellowish nodules on the cut surface. The characteristic and common histopathologic findings include multifocal necrosis with hemorrhage of the lung, severe lymphoid depletion of the spleen and intracytoplasmic or intranuclear inclusion bodies in almost all organs. Finally, CDV and S. canis were identified by immunohistochemistry and bacterial isolation, respectively. This is the first mixed infection case of CDV and S. canis in badgers being raised on the farm.

• Korean Journal of Veterinary Research
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• v.58 no.1
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• pp.27-31
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• 2018

Canine coronavirus is a single-stranded RNA virus that causes enteritis in dogs of any age. Coronaviral enteritis is seldom definitively diagnosed, since it is usually much less severe than many other types of enteritis and is self-limiting. Conventional diagnostics for the canine coronaviral enteritis such as polymerase chain reaction (PCR), virus isolation, and electron microscopic examination are inappropriate for small animal clinics due to the complicated experimental processes involved. Therefore, a commercially available lateral flow test kit based on chromatographic immunoassay techniques was tested to evaluate its performance as a first-line diagnostic test kit that could be used in clinics. The coronavirus antigen test kit detected canine coronavirus-infected dogs with 93.1% sensitivity and 97.5% specificity. The detection limit of the test kit was between $1.97{\times}10^4/mL$ and $9.85{\times}10^3/mL$ for samples with a 2-fold serial dilution from $1.25{\times}10^6\;TCID_{50}$ ($TCID_{50}$, 50% tissue culture infectious dose). Additionally, the test kit had no cross-reactivity with canine parvovirus, distemper virus, or Escherichia coli. Overall, the commercially available test kit showed good diagnostic performance in a clinical setting, with results similar to those from PCR, confirming their potential for convenient and accurate use in small animal clinics.

• Journal of fish pathology
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• v.25 no.3
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• pp.143-150
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• 2012

Infectious haematopoietic necrosis virus (IHNV) is an important fish pathogen that infects both wild and cultured salmonids. Since the first isolation of IHNV from rainbow trout and masu salmon in 1991, a series of IHN disease outbreak has been reported in Korea. In 2011, we isolated two IHNV isolates from rainbow trout cultured in Korea. The full open-reading frame (ORF) encoding the glycoprotein (G) of them were sequenced and the amino acid sequences were phylogenetically analyzed. Phylogenetic analysis of the G revealed that both IHNV isolates were grouped into an Asian genogroup containing Korean IHNV isolates and Japanese IHNV isolates. However, based on their sequence variation, they were divided into different subgroup. While one isolate was similar to other Korean isolates, the other isolate showed a high level of similarity with Japanese isolates, suggesting the possibility of influx of new IHNV strain into Korea.

• Korean Journal of Veterinary Research
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• v.61 no.3
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• pp.23.1-23.8
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• 2021

Porcine epidemic diarrhea (PED) is characterized by acute enteritis, watery diarrhea, weight loss, dehydration, and death with high mortality in neonatal piglets. In this study, 3 virus isolates collected in Vietnam between 2016 and 2017 were successfully propagated in Vero cells at high virus titers. Sequence analysis of the full-length spike (S) gene revealed that all 3 isolates belong to genogroup 2a, which is closely related to other prevalent Asian strains. Amino acid sequence comparisons revealed 98.19% to 99.13% homology with the Vietnam isolates circulating during 2013-2015, suggesting that field PED viruses (PEDVs) evolve continuously. Experiments in animals demonstrated that antisera from guinea pigs immunized with the vaccine strain resulted in higher levels (5 log₂) of neutralizing antibody against the homologous strain, and showed a relatively lower level of neutralizing antibody against the field isolates. This finding would be helpful in choosing a PEDV strain for vaccine development.

• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.422-429
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• 2022

The hepatitis C virus (HCV) genome contains a positive-sense single-stranded RNA molecule, and it is classified into 8 genotypes and 87 subtypes. Globally, over 350,000 people die from liver cirrhosis and hepatocellular carcinoma caused by HCV each year. Here, the genotype distribution of HCV was estimated in the population in Cheonan, Korea using Sanger sequencing. In addition, the correlation between HCV RNA level and genotype was assessed using real-time polymerase chain reaction (PCR); similarly, the correlation of HCV RNA level with isolation year (2007-2016) was determined using 463 consecutive serum samples obtained from patients at Dankook University Hospital, Cheonan, Korea. In 2007, genotype 1b (54.2%) was predominant, followed by genotypes 2a (41.7%), 1a (2.1%) and 3a (2.1%); whereas in 2016, the predominant genotype was 2a (49.0%), followed by genotypes 1b (46.9%), 3b (2%), and 4a (2%). Neither age nor sex was correlated with HCV genotype. Furthermore, the mean HCV RNA level decreased significantly from 2012 to 2016 (p < 0.05). However, no significant correlations between genotype and HCV RNA level were found. Overall, the findings revealed that genotypes 2a and 1b were the most common in Cheonan, and the prevalence of HCV genotype 1b tended to decrease over the past decade.

• Korean Journal of Veterinary Research
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• v.63 no.2
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• pp.18.1-18.8
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• 2023

Porcine epidemic diarrhea (PED) is characterized by acute enteritis, watery diarrhea, weight loss, dehydration, and death, with high mortality in neonatal piglets. In this study, 3 virus isolates collected in Vietnam between 2016 and 2017 were propagated successfully in Vero cells at high virus titers. Sequence analysis of the full-length spike (S) gene showed that all 3 isolates belong to genogroup 2b, which is closely related to other prevalent Asian strains. A comparison of the amino acid sequence revealed a 98.19% to 99.13% homology with the Vietnam isolates circulating during 2013-2015, suggesting that field PED viruses (PEDVs) are evolving continuously. Experiments in animals showed that the antisera from guinea pigs immunized with the vaccine strain resulted in higher levels (5 log₂) of neutralizing antibodies against the homologous strain and a relatively moderate level of neutralizing antibodies against the field isolates. This finding would be helpful in selecting a PEDV strain for vaccine development.

• Korean Journal of Veterinary Research
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• v.64 no.2
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• pp.13.1-13.6
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• 2024

Avian influenza A viruses (IAVs) present significant threats to both animal and human health through their potential for cross-species transmission and global spread. Clade 2.3.4.4 H5Nx highly pathogenic avian IAVs initially emerged in East Asia between 2013 and 2014. Since then, they have spread to Europe, Africa, and America via migratory bird flyways. However, beyond viral transmission primarily facilitated by migratory birds, the potential involvement of other intermediate factors for virus transmission remains poorly investigated. This study aimed to investigate the role of wild rodents as intermediary hosts in the ecology of avian IAVs in Gyeonggi province, South Korea. By capturing and analyzing 189 wild rodents near poultry farms and migratory bird habitats in 2013 and 2014 and employing serological assays and virus isolation techniques, we found no evidence of IAV infection among these populations. Our results suggest that wild rodents may not significantly contribute to the transmission dynamics of IAVs within these regions.