• Journal of Veterinary Science
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• v.22 no.4
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• pp.48.1-48.15
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• 2021

Background: Porcine epidemic diarrhea virus (PEDV) is a swine enteropathogenic coronavirus that has devastated the swine industry in South Korea over the last 30 years. The lack of an effective method to control the endemics has led to a surge in PEDV recurrences in affected farms throughout the country. Objectives: In the first step toward establishing systematic monitoring of and active control measures over the swine populations, we constructed an assessment model that evaluates the status of (1) biosecurity, (2) herd immunity, and (3) virus circulation in each of the PEDV-infected farms. Methods: A total of 13 farrow-to-finish pig farms with a history of acute PEDV infection on Jeju Island were chosen for this study. The potential risk of the recurrence in these farms was estimated through on-site data collection and laboratory examination. Results: Overall, the data indicated that a considerable number of the PEDV-infected farms had lax biosecurity, achieved incomplete protective immunity in the sows despite multi-dose vaccination, and served as incubators of the circulating virus; thus, they face an increased risk of recurrent outbreaks. Intriguingly, our results suggest that after an outbreak, a farm requires proactive tasks, including reinforcing biosecurity, conducting serological and virus monitoring to check the sows' immunity and to identify the animals exposed to PEDV, and improving the vaccination scheme and disinfection practices if needed. Conclusions: The present study highlights the significance of coordinated PEDV management in infected farms to reduce the risk of recurrence and further contribute towards the national eradication of PEDV.

• Parasites, Hosts and Diseases
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• v.60 no.1
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• pp.65-71
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• 2022

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a zoonotic, tick-borne RNA virus of the genus Bandavirus (Family Phenuiviridae), mainly reported in China, Japan, and the Republic of Korea (Korea). For the purpose of this study, a total of 3,898 adult and nymphal ticks of species Haemaphysalis longicornis (94.2%), Haemaphysalis flava (5.0%), Ixodes nipponensis (0.8%), and 1 specimen of Ixodes ovatus, were collected from the Deogyusan National Park, Korea, between April 2016 and June 2018. A single-step reverse transcriptase-nested PCR was performed, targeting the S segment of the SFTSV RNA. Total infection rate (IR) of SFTSV in individual ticks was found to be 6.0%. Based on developmental stages, IR was 5.3% in adults and 6.0% in nymphs. The S segment sequences obtained from PCR were divided into 17 haplotypes. All haplotypes were phylogenetically clustered into clades B-2 and B-3, with 92.7% sequences in B-2 and 7.3% in B-3. These observations indicate that the Korean SFTSV strains were closer to the Japanese than the Chinese strains. Further epidemiological studies are necessary to better understand the characteristics of the Korean SFTSV and its transmission cycle in the ecosystem.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.239-252
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• 2012

The circulation and infection of avian influenza virus (AIV) in zoos and backyard flocks has not been systematically investigated. In the present study, we surveyed the birds including those in live bird markets (LBMs) and evaluated co-circulation of AIVs among them. Overall, 26 H9N2 AIVs and one H6N2 AIV were isolated from backyard flocks and LBMs, but no AIVs were isolated from zoo birds. Genetic analysis of the HA and NA genes indicated that most of the H9N2 AIVs showed higher similarities to AIVs circulating in domestic poultry than to those in wild birds, while the H6N2 AIV isolate from an LBM did to AIVs circulating in migratory wild birds. In serological tests, 15% (391/2619) of the collected sera tested positive for AIVs by competitive-ELISA. Among them, 34% (131/391) of the sera tested positive for AIV H9 antigen by HI test, but only one zoo sample was H9 positive. Although AIVs were not isolated from zoo birds, the serological results indicated that infection of AIVs might occur in zoos. It was also confirmed that H9N2 AIVs continue to circulate and evolve between backyard flocks and LBMs. Therefore, continuous surveillance and monitoring of these flocks should be conducted to control further epidemics.

• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.371-379
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• 2006

Newcastle disease virus (NDV) is a single-stranded negative sense RNA virus, which has been classified as a member of the Avulavirus genus of the Paramyxoviridae family. It is also one of the most important pathogens in the poultry industry. The glycoproteins, fusion (F) and hemagglutinin-neuraminidase (HN), determine the virulence of NDV, and the relevant molecular structures have already been determined. NDV isolates differ in terms of virulence, and at least 2 of 9 genotypes (I-IX) have been shown to co-circulate. Therefore, it is clearly important to differentiate between vaccine strains and field isolates. In vivo pathogenicity tests have been the standard protocol for some time, but molecular methods appear preferable in terms of the rapidity of diagnosis, as well as animal welfare concerns. In this study, we have designed primer sets from HN gene for phylogenetic analysis and restriction enzyme analysis, and from F gene for pathotype-specific RT-PCR. Via the combination of 2 methods, 106 Korean NDV isolates obtained from 1980 to 2005 were differentiated into vaccine strains, and virulent genotypes VI and VII. The genotype VI viruses were only rarely isolated after 1999, and genotype VII, after it was initially isolated from poultry in 1995, recurred in 2000, and then became the main NDV constituting a threat to the Korean poultry industry.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2743-2748
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• 2014

Novel 4'-trifluoromethyl-5'-norcarbocyclic purine phosphonic acid analogs were efficiently synthesized from commercially available 1,3-dihydroxy cyclopentane (5). Trifluoromethylation was successfully performed by using the Ruppert-Prakash reaction. The purine nucleosidic bases were efficiently coupled by using the Mitsunobu reaction. The synthesized adenosine phosphonic acids analogs 13 and 16 were screened for antiviral activity against human immunodeficiency virus-1 (HIV-1). Adenine derivative 13 exhibited significant anti-HIV-1 activity.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2039-2042
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• 2009

As a part of an ongoing effort to discover inhibitors of the Hepatitis C Virus RNA replication, we describe here the first synthetic route of 1'($\alpha$),2'($\beta$)-C-dimethyl carbocyclic adenine analogue. The key intermediate cyclopentenyl alcohol 8($\alpha$) was prepared from aldehyde 4 using ring-closing metathesis (RCM) as a key reaction. Coupling of 8($\alpha$) with nucleosidic base via the regioselective Mitsunobu reaction followed by stereoselective dihydoxylation and deprotection afforded the target carbocyclic adenine analogue 12.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3348-3352
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• 2010

Novel 4'-ethyl-5'-norcarbocyclic adenosine phosphonic acid analogues were synthesized from propionaldehyde 5 through a de novo acyclic synthetic route using reiterative Grignard additions and ring-closing metathesis (RCM) as key reactions. The synthesized nucleoside phosphonic acids analogues 17, 18, 19, and 21 were subjected to antiviral screening against human immunodeficiency virus.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2989-2992
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• 2009

An efficient synthetic route of novel 2′(${\alpha}$)-C-fluoro-2′(${\beta}$)-C-methyl carbocyclic nucleoside analogues is described. The key fluorinated intermediate 7 was prepared from the epoxide intermediate 5 via selective ring-opening of epoxide. Coupling of 7 with nucleosidic bases under the Mitsunobu reactions followed by deprotection afforded the target carbocyclic nucleoside analogues. The synthesized compounds were evaluated as inhibitors of the hepatitis C virus (HCV) in Huh-7 cell line in vitro.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.924-939
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• 2016

The great economic losses caused by Cucumber mosaic virus (CMV) infection of peppers has led to the development of genetically modified (GM) CMV-resistant peppers. We developed virus-resistant pepper plants using Agrobacterium tumefaciens -mediated transformation. The expressed recombinant protein was purified using nickel-nitrilotriacetic acid resin and immunoaffinity chromatography, and purity was assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Immunoblot analysis revealed the purified CMV coat protein (CMV-CP) had a molecular mass of 25 kDa. After in-gel digestion and desalting, the internal peptide fragments of CMV-CP were sequenced by matrix-assisted laser desorption/ionization-time of flight. Most GM pepper and Escherichia coli BL21 internal peptides had identical peptide sequences and contained 137 of 183 whole peptides in CMV-CP. A quantitative enzyme-linked immunosorbent assay was performed to detect CMV-resistant GM peppers. We also provide basic information about the expressed protein in GM peppers for further safety assessment. The contents of soluble protein and CMV-CP were measured in GM and control peppers cultivated in three different areas of Korea. Statistical significance in terms of cultivation areas, harvest times, generations, and plant tissue origin were determined based on a P value of 0.05. The highest amount of CMV-CP was detected at the seedling stage from plant grown in each region. T3 and T5 showed significantly different levels of CMV-CP from T4 in leaves in the whorl stage. No statistical differences were observed among GM peppers at different stages of maturity in any cultivation area. The results from this study contribute to the safety evaluation of newly designed CMV-resistant GM peppers and provide a standard against which to compare other virus-resistant GM peppers.

• Journal of Yeungnam Medical Science
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• v.26 no.2
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• pp.143-147
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• 2009

Hemorrhagic cystitis (HC) is a common complication after allogeneic transplantation. Early posttransplant HC occurs in association with cyclophosphamide, while later on HC results from viral infections such as polyomavirus BK (BKV) and adenovirus. We report here the case of a 57-year-old woman who received an instillation of cidofovir into the bladder for the treatment of hemorrhagic cystitis after allogeneic peripheral stem cell transplantation for her acute myeloid leukemia. Cyclophosphamide and busulfan were used as conditioning treatments. Cyclosporin was administered daily. On the 71st day after transplantation, the patient developed acute severe hemorrhagic cystitis, and BK virus was demonstrated in the urine samples using polymerase chain reaction. Her urinary symptoms did not improve in spite of palliative treatment, but a response was evident after intravesical cidofovir treatment.