Publications by authors named "YouChan Bae"

Article Synopsis
  • The study examines cases of bovine abortions in South Korea caused by an opportunistic bacterium, focusing on its pathological findings, antimicrobial resistance, and genetic traits.
  • Three bovine abortion cases revealed severe lung issues and other infections, with bacterium detected in all affected fetuses; two were attributed solely to the bacterium, while one was associated with a viral coinfection.
  • This marks the first report of such abortions linked to this bacterium in South Korea, highlighting the need for ongoing research to understand its characteristics and resistance patterns.
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Jejunal haemorrhage syndrome (JHS) is a sporadic and fatal enterotoxaemic disease in dairy cows associated with acute development and poor prognosis despite treatment. A 5-year-old Holstein cow with no reported pregnancy, three calving numbers, and 303 days in milk presented with hypothermia, discomfort, and inappetence. Anaemia, dehydration, faeces with blood clots, and absence of rumen and bowel movements were observed.

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  • Influenza D virus (IDV), found first in 2011 in pigs in the U.S., is part of the Orthomyxoviridae family and primarily affects cattle, which are its natural reservoir.
  • A study conducted in South Korea in 2022 found IDV viral RNA in 1.4% of cattle tested, while none was detected in pigs, indicating a low prevalence in the region.
  • The seroprevalence results showed 54.7% of cattle and 1.4% of pigs had antibodies for IDV, marking the first detection of the virus and its antibodies in South Korea.
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Background: Since 2013, the number of requests for diagnosis for horses based on neurological symptoms has increased rapidly in South Korea. The affected horses have commonly exhibited symptoms of acute seasonal hindlimb ataxia. A previous study from 2015-2016 identified as the causative agent.

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Since June 2020, the Y280 lineage H9N2 virus, which is distinct from the previously endemic Y439 lineage, has been circulating in poultry in Korea. In this study, we developed two whole inactivated vaccines, rgHS314 and vac564, against the Y280 and Y439 lineages, respectively, and evaluated their immunogenicity and protective efficacy against homologous or heterologous viral challenge in mice. Serum neutralizing antibody titers in the rgHS314-vaccinated group were higher (68 ± 8.

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  • * A study analyzed 46 IBV isolates from South Korea (2003-2019) and found a new cluster of recombinant strains with unique genomic sequences, indicating significant genetic diversity.
  • * The study revealed that these recombinant strains (rGI-19s) may cause more trachea infections but are less pathogenic in kidneys compared to traditional GI-19 strains, highlighting the impact of genetic recombination on disease severity.
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This study was performed to examine and clarify the cause of hindlimb ataxia and neuropathy seen in the South Korean horse population. Fifty horses diagnosed with hindlimb ataxia and neuropathy were referred for this study. Neurological examination was performed on 47 horses while necropsy was performed in all 50 animals.

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H5 and H7 subtypes of low pathogenic avian influenza viruses (LPAIVs) can mutate to highly pathogenic forms and are therefore subject to stringent controls. We characterized H5 LPAIVs isolated from wild-bird habitats and duck farms in South Korea from 2010 to 2017. Through nationwide active surveillance for AIVs, 59 H5 LPAIVs were isolated from wild-bird habitats (a mean annual rate of 5.

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Article Synopsis
  • - The study focuses on Runting-Stunting Syndrome (RSS) in chickens, a disease causing significant economic losses due to malabsorption, which has unclear causes despite decades of research.
  • - Researchers analyzed viral metagenomes from four affected chicken flocks using next-generation sequencing and developed specific primers to identify various enteric viruses linked to RSS.
  • - Findings revealed a strong association between chicken astrovirus and RSS, with this virus detected in all samples; additionally, two previously unreported viruses were discovered, contributing to a better understanding of viral presence in chicken enteric diseases.
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The emergence of novel highly pathogenic avian influenza viruses (HPAIVs) in migratory birds raises serious concerns as these viruses have the potential to spread during fall migration. We report the identification of novel HPAIV A(H5N8) clade 2.3.

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spp. are opportunistic pathogens that cause lameness in broiler chickens, resulting in serious economic losses worldwide. Virulence of spp.

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Bacterial chondronecrosis with osteomyelitis (BCO) is a major cause of lameness in broiler chicken, and results in serious economic losses worldwide. Although the pathogenesis mechanism leading to lameness is not entirely understood, some strains of Enterococcussp., avian pathogenic Escherichia coli or Staphylococcus aureus have been long recognized as important causative pathogens.

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In December 2016, highly pathogenic avian influenza (HPAI) infection with systemic pathologic lesions was found in cats in South Korea. Genetic analyses indicated that the feline isolates were similar to HPAI H5N6 viruses isolated in chicken farms nearby. This finding highlights the need for monitoring of domestic mammals during HPAI outbreaks.

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In this study, we characterized H7 subtype low-pathogenicity (LP) influenza A viruses (IAVs) isolated from wild bird habitats in the Republic of Korea from 2010 to early 2017. Through national surveillance, 104 H7 IAVs were isolated, accounting for an average of 14.9% of annual IAV isolations.

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Avian infectious bronchitis viruses (IBVs) with the TC07-2 genotype have spread rapidly in East Asia since they were first reported in China in 2007. In 2015, an IBV with the TC07-2 genotype (designated KrD1515) was isolated from layer chickens with severe respiratory symptoms in Korea. In the present study, the full-length open reading frames of the spike (S) and nucleocapsid (N) genes of the virus were sequenced and analyzed.

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Loop-mediated isothermal amplification (LAMP) methods to detect chicken infectious anemia virus (CIAV), reticuloendotheliosis virus (REV), and Marek's disease virus (MDV), and a reverse transcription (RT)-LAMP assay to detect infectious bursal disease virus (IBDV), were developed. The CIAV-LAMP, REV-LAMP, MDV-LAMP, and IBDV-RT-LAMP methods were performed using four sets of six primers targeting the VP1 gene of CIAV, the gp90 gene of REV, the Meq gene of MDV, and the VP2 gene of IBDV. The results (a change in color) were observed visually.

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We report the identification of novel highly pathogenic avian influenza viruses of subtype H5N6, clade 2.3.4.

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A highly pathogenic avian influenza (HPAI) H5N8 virus was first detected in poultry and wild birds in South Korea in January 2014. Here, we determined the pathogenicity and transmissibility of three different clades of H5 viruses in mandarin ducks to examine the potential for wild bird infection. H5N8 (clade 2.

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Highly pathogenic avian influenza (HPAI) virus of the H5N8 subtype was isolated from a young ostrich in South Korea in March 2014. Clinical signs characterized by anorexia, depression, and signs of nervousness were observed. The isolated A/ostrich/Korea/H829/2014 (H5N8) virus had a cleavage site motif containing multiple basic amino acids, typical of HPAI virus.

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Bovine tuberculosis caused by Mycobacterium bovis has a wide range of hosts including cattle and humans, but its incidence in otters is very rare. Our report describes a case of bovine tuberculosis in an Asian small-clawed otter (Aonyx cinerea). A deceased female otter ~2-3 years of age that was raised in an aquarium was submitted to the Animal and Plant Quarantine Agency (Anyang, Republic of Korea) for autopsy in June 2013.

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This paper describes a novel diagnostic method for the detection of avian botulism caused by Clostridium botulinum type C and C/D, using single-tube nested PCR assay. This assay was developed to overcome the disadvantages of bioassays used in experiments with mice. Three primer pairs including an antisense primer were designed to target the N-terminal of the toxin gene from C.

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In January 2014, an outbreak of infection with highly pathogenic avian influenza (HPAI) A(H5N8) virus began on a duck farm in South Korea and spread to other poultry farms nearby. During this outbreak, many sick or dead wild birds were found around habitats frequented by migratory birds. To determine the causes of death, we examined 771 wild bird carcasses and identified HPAI A(H5N8) virus in 167.

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