Yoon-Young Cho

Phylogenetic analysis of astrovirus and kobuvirus in Korean dogs.

ABSTRACT Astroviruses and kobuviruses are frequently found in mammalian feces, including that of humans. The present study examined fecal samples from 91 Korean dogs suffering from diarrhea. Canine astroviruses (CAstVs) and canine kobuviruses (CKoVs) were identified in 2 (2.1%) and 46 (50.6%) dogs, respectively. Nucleotide sequence analysis coupled with phylogenetic analysis using the neighbor-joining method showed that CAstVs clustered into four genetically diverse groups. Two Korean CAstVs belonged to group 2 alongside strains isolated in Italy and France. Twelve of the Korean CKoVs belonged to a single clade, along with strain UK003 identified in the UK and six CKoVs identified in the USA. Thus, the results suggest that the Korean strain of CAstV is closely related to strains isolated in Europe. Surely, CKoV in South Korea could identify the circulation among dogs population.

Complete Genome Sequence of K14JB01, a Novel Variant Strain of Porcine Epidemic Diarrhea Virus in South Korea.

ABSTRACT A novel variant strain of porcine epidemic diarrhea virus (PEDV) emerged on pig farms in South Korea during late 2013. Genomic DNA isolated from a K14JB01 strain identified in a diarrheal pig showed high sequence similarity to PEDV strains prevailing in the United States in 2013. This is the first study to identify the complete genome sequence of a novel variant PEDV in South Korea.

Serological prevalence of viral agents that induce reproductive failure in South Korean wild boar

BackgroundViral agents associated with reproductive failure such as Aujeszky’s disease virus (ADV), encephalomyocarditis virus (EMCV), and porcine parvovirus (PPV) have also been identified in European wild boar. To screen for the presence of antibodies against ADV, EMCV, and PPV from wild boar (Sus scrofa) in South Korea, 481 serum samples were collected from wild boar hunted between December 2010 and May 2011.ResultsOf the 481 serum samples tested, 47 (9.8%) and 37 (7.7%) were seropositive for ADV and EMCV antibodies, respectively, based on a neutralization test (VNT), and 142 (29.5%) were seropositive for PPV antibodies based on a hemagglutination inhibition (HI) test.ConclusionsThis was the first survey to identify the seroprevalence of the three major viruses associated with reproductive failure in the wild boar population of South Korea. Wild boar may act as a reservoir for many viruses that cause infectious diseases in domestic pigs. Thus, strict prevention and control measures, such as continuous wildlife disease surveillance and strategic methods of downsizing the population density, should be implemented to prevent disease transmission from wild boar to domestic pigs.

Detection of H3N2 canine influenza virus using a Quartz Crystal Microbalance

Label-free technology-based Quartz Crystal Microbalance (QCM) is an emerging tool in biological research. In this study, QCM was applied successfully for the rapid diagnosis of H3N2 canine influenza virus (CIV) infection. ProLinker™ B, a calixcrown derivative, enables antibodies to be attached to a gold-coated quartz surface and positioned in a regular pattern with the correct orientation. The ProLinker-coated quartz-based assay detected H3N2 CIV at lower concentrations (2(2) HA unit) than a commercial immunochromatography Ag kit (2(3) HA unit). Three independent experiments in which H3N2 CIV-positive reference samples were applied to an anti-CIV nucleoprotein (NP) monoclonal antibody immobilized on a quartz surface yielded standard deviations (SD) of ≤5%, indicating high reproducibility. In addition, the QCM assay with a cut-off value (-140 Hz) showed 97.1% (34/35) sensitivity and 94.7% (36/38) specificity in testing 73 field saliva samples, respectively. Thus, the QCM assay described herein will be a valuable tool for the rapid diagnosis of H3N2 CIV infection with high sensitivity and specificity, and should overcome several of the disadvantages and limitations inherent in the commercial immunochromatography Ag kit.

Genetic characterization of porcine circovirus type 2 in the Korean wild boar population.

The porcine circovirus type 2 (PCV2) has reached very high levels in the pig population in South Korea and throughout the world since it was first described in the late 1990s. In this study, we found that the prevalence of PCV2 in the Korean wild boar population was 4.98% (91/1825). Interestingly, 19 PCV2 ORF2 sequences that could be completely sequenced showed that they belonged only to genotype PCV2b, subgroup 1A/B (n=16) and 1C (n=3). We suggest that sites potentially under positive selection are responsible for the antigenicity changes and phenotypic switch patterns in the capsid gene of 55 PCV2s from Korean domestic pigs, but the sites potentially under positive selection in the 19 PCV2 ORF2 genes from Korean wild boar are not responsible for antigenicity.

Molecular characterisation and phylogenetic analysis of feline astrovirus in Korean cats.

Astroviruses (AstVs) are important pathogens associated with enteric diseases in humans and other animals. However, most animal AstVs, including feline astrovirus (FAstV), are poorly understood. The aim of the present study was to investigate the prevalence and association of FAstV with enteric diseases in cats, and to conduct a molecular analysis of FAstVs, in Korea. Eleven faecal samples from 62 hospitalised cats at animal hospitals in the Moran market in South Korea tested positive for FAstV. The prevalence of FAstV was higher in cats <2 months old (25%) than in cats >2 months old (14.3%) (P = 0.31). Diarrhoea and normal faeces were observed in 19% (8/42) and 15% (3/20) of cats with FAstV, respectively (P = 1.00). Amino acid sequences alignment and phylogenetic tree analysis showed that FAstVs, including Korean strains, formed a single clade within the mamastroviruses.

Molecular Characterization of the Full Kobuvirus Genome in a Cat

ABSTRACT Kobuviruses, which belong to the family Picornaviridae, have been detected in fecal samples from infected animals with or without diarrhea. Here, we report the first complete genome sequence of a feline kobuvirus (FKoV) strain, FK-13, identified from the feces of a cat with diarrhea in South Korea in 2011.

Surveillance of classical swine fever in wild boar in South Korea from 2010–2014

Classical swine fever (CSF) is a highly contagious systemic hemorrhagic viral disease of pigs. Wild boar plays a crucial role in the epidemiology of CSF. Between 2010 and 2014, samples were collected nationwide from 6,654 wild boars hunted in South Korea. Anti-CSF antibodies were identified in 0.59% (39 of 6,654) of the wild boar samples using a virus neutralization test and were primarily detected in wild boars living close to the demilitarized zone and the area of the Taebaek Mountains surroundings. The CSF virus (subgroup 2.1b) was isolated from two wild boars captured in a nearby border area. The criteria used to define high-risk areas for targeted CSF surveillance in South Korea should be further expanded to include other regions nationwide.

Serological evidence for influenza virus infection in Korean wild boars

Serum samples from 1,011 wild boars hunted in 2012 were collected for serological surveillance for 4 subtypes (pandemic A (H1N1) 2009 and classical H1N1, H1N2 and H3N2) of swine influenza virus (SIV). Samples from 12 of the boars were identified as positive for SIV (pandemic A (H1N1) 2009, n=9; classical H1N1, n=2; and H1N2, n=1) by a hemagglutination inhibition test (HI test) and a nucleoprotein (NP)-based enzyme-linked immunosorbent assay (NP-ELISA). Although the overall seroprevalence of SIV in the Korean wild boar population was somewhat low compared with that in China and the U.S.A., the apparent prevalence of pandemic H1N1 was notable. Therefore, continuous monitoring of the wild boar population is needed as it may be a major reservoir for pandemic H1N1, facilitating its spread to humans and domestic pigs.