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Porcine epidemic diarrhea virus (PEDV) is a highly contagious enteric pathogen of swine. PEDV has been a major problem in the pig industry since its first identification in 1992. The aim of this study was to investigate the diversity, molecular characteristics, and phylogenetic relationships of PEDVs in field samples from Korea. Six PEDVs were identified from the field samples, and the full spike (S) glycoprotein gene sequences were analyzed. A phylogenetic analysis of the S gene sequences from the six isolates revealed that they were clustered into the G2b subgroup with genetic distance. The genetic identity of the nucleotide sequences and deduced amino acid sequences of the S genes of those isolates was 97.9-100% and 97.4-100%, respectively. A BLAST search for new PEDVs revealed an identity greater than 99.5% compared to the highest similarity of two different Korean strains. The CO-26K equivalent (COE) epitope had a 521H→Y/Q amino acid substitution compared to the subgroup G2b reference strain (KNU-1305). The CNU-22S11 had 28 amino acid substitutions compared to the KNU-1305 strain, which included two newly identified amino acid substitutions: 562S→F and 763P→L in the COE and SS6 epitopes, respectively. Furthermore, the addition and loss of N-linked glycosylation were observed in the CNU-22S11. The results suggest that various strains of PEDV are prevalent and undergoing evolution at swine farms in South Korea and can affect receptor specificity, virus pathogenicity, and host immune system evasion. Overall, this study provides an increased understanding of the prevalence and control of PEDV in South Korea.

The health-beneficial outcomes of doenjang, a Korean fermented food have been questioned due to its high salt content; moreover, the detailed underlying mechanisms of its health beneficial effects are not fully investigated. Thus, this study aimed to investigate doenjang's anti-obesity effects, anti-hypertensive effects, and its underlying mechanisms in high-fat diet -induced obesity. Sprague-Dawley rats fed with normal diet (ND), high-fat diet (HD), HD with 8% additive salt (HDS), or HD with doenjang containing 8% salt (HDJ) for 13 weeks. Compared to HD and HDS groups, the HDJ group had lower body and epididymal fat tissue weight gain and showed hypotrophy and hypoplasia. The RAS-related mRNA levels in the adipose tissue, including Renin and Ace were downregulated in the HDJ group compared to HD and HDS groups. Additionally, HDJ groups had significant improvements in systolic blood pressure, serum RAS-associated parameters (e.g., angiotensin II and aldosterone), renal mRNA levels related to RAS (e.g., angiotensin II receptor type 1 and 2), and aldosterone-associated mRNA expressions (e.g., mineralocorticoid receptor) in the kidney of HD-induced obese rats. Most importantly, HDS and HDJ groups showed distinct outcomes regarding adipogenesis and electrolytes metabolism, even though both diets contain a high level of salt. HDS group showed a higher epididymal fat tissue weight, mass, and adipocyte size than HDJ group. In addition, compared with HDJ group, HDS group significantly decreased the release of Na+ and K+ throughout the urine and feces. The present study addresses that doenjang has anti-obesity effects and anti-hypertensive effects by activating RAS in the adipose tissue and kidney, respectively. Additionally, this study also demonstrates that salt in doenjang and the additive salt differently influences adipogenesis and electrolytes metabolism, supporting doenjang has health advantageous effects regardless of its high salt contents., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2023 Woo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Food security is important for human health and quality of life. This study investigated the association between food security and the number of remaining teeth in Korean adults. Raw data from the Korea National Health and Nutrition Examination Survey (KNHANES) VII (2016-2018) were analyzed, including data from 13,199 adults aged 19 years or older. The associations between food security and number of teeth were assessed using multiple multinomial logistic regression models after adjusting for demographic and health factors as covariates. In the model adjusted for all socioeconomic, medical, and behavior variables, the odds ratio of tooth loss (16-20 teeth) was 3.80 (95% confidence interval [CI] 1.56-9.21) in the group of people that reported often feeling insecurity regarding various food groups compared to those who reported feeling food security. The results of this study demonstrated an association between food security and the number of remaining teeth in Korean adults. Therefore, food security is essential for improving lifelong oral health.

Purpose: To examine the association between the intake of various nutrients (phosphorus, riboflavin, thiamine, niacin, vitamin C, calcium, protein, carbohydrates, and fat) and the prevalence of periodontal disease in Korean adults., Materials and Methods: The data used for analysis were obtained from the 7th Korea National Health and Nutrition Examination Survey (2016-2018). Data from 12,689 adults aged ≥ 19 years who had a periodontal examination were analysed. Data were analysed using the Chi2 and t-tests. Multiple regression analysis was used to assess the association between the selected nutrients and periodontal diseases., Results: After adjusting for sex, age, income, body mass index, diabetes, smoking, alcohol consumption, and toothbrushing frequency, a statistically significant relationship between phosphorus, carbohydrate, and fat intake and the risk of periodontal disease was identified by multiple logistic regression analysis (odds ratio [OR]: 0.80, 95% confidence interval [CI]: 0.66-0.97; OR: 0.85, 95% CI: 0.70-0.98, OR: 1.41, 95% CI: 1.13-1.75, respectively)., Conclusion: Phosphorus, carbohydrates and fat were associated with periodontal disease. Therefore, the improvement of diet should be emphasised to prevent and manage periodontal disease. Further research is needed based on various nutrients related to periodontal disease in the future.

This study aimed to investigate the association between healthy lifestyle (HLS; i.e., diet quality, physical activity, normal weight) and periodontal diseases in Korean adults. Studying this association may help inform future intervention programs aimed at preventing the development of periodontal diseases. Raw data of the Korea National Health and Nutrition Examination Survey (KNHANES) VII (2016-2018) were used. Data from 12,689 adults aged 19 years and over who had a periodontal examination were analyzed. The associations between HLS and periodontal diseases were analyzed using multivariate logistic regression after adjusting for demographic and health factors as covariates. We found that each of the HLS (diet quality, physical activity, normal body weight) practices was significantly associated with periodontal diseases (OR: 1.32, 95% CI: 1.13-1.55; OR: 1.16, 95% CI: 1.04-1.30; OR: 1.26, 95% CI: 1.14-1.40, respectively). In particular, having poor HLS practices was identified as a risk factor for periodontal diseases (OR: 1.54, 95% CI: 1.10-2.15). HLS was associated with periodontal diseases. Thus, in addition to improving oral hygiene-the primary focus in the past-improving HLS should be emphasized for patients with periodontal diseases.

This study aimed to investigate the correlations among Stress and Anxiety to Viral Epidemics (SAVE), job stress (JS), and burnout among Korean dental hygienists during the COVID-19 pandemic and to identify the moderating effect of JS. As a cross-sectional study, a self-reporting questionnaire was used to survey 204 clinical dental hygienists to measure the levels of SAVE, JS, and burnout, along with their demographic characteristics as the control variables. Pearson correlation analysis and hierarchical multiple regression analysis were performed to analyse the correlations among burnout, SAVE, and JS, including the moderating effect of JS. With education level and subjective health controlled, JS (β = 1.05, p < 0.001), SAVE (β = 0.69, p = 0.020) and the interaction between SAVE and JS (β = −0.93, p = 0.050) were identified as significant influencing factors of burnout. The adjusted explanatory power of the model was found to be 52.4%. In summary, both SAVE and JS were significant influencing factors of burnout among dental hygienists, while a moderating effect of JS was also identified. Therefore, it is necessary to create a work environment that can relieve SAVE and JS to reduce burnout among dental hygienists.

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.

Purpose: Evidence-based practice (EBP) is a key competency that undergraduate nursing students need to learn, as EBP competence is essential for the effective implementation of EBP. However, few studies have comprehensively assessed the aspects of EBP competence using a reliable and valid measure specific to Korean nursing students. This study aimed to translate the Student Evidence-Based Practice Questionnaire (S-EBPQ) into Korean and evaluate its psychometric properties., Methods: The original S-EBPQ was translated into Korean. After a pilot test, a convenience sample of 249 college students with more than four weeks of clinical training experience was selected from three universities in September 2017. Reliability and construct validity were evaluated using exploratory and confirmatory factor analyses. Concurrent validity was evaluated by correlating the measure with informatics competency., Results: The exploratory factor analysis revealed four factors that explained 66.3 of the variance. The confirmatory factor analysis yielded a 4-factor structure (χ 2 /df = 1.52, p < .001, standardized root-mean-square residual = .07, root-mean-square error of approximation = .07, goodness of fit index = .84, comparative fit index = .91). The Cronbach's α was .81 for the total scale. The scale's correlation with informatics competency was r = .55., Conclusions: The Korean S-EBPQ is a reliable and valid tool that has utility for assessing EBP competence in Korean nursing students and for making comparisons of the EBP competence of nursing students from other countries., Competing Interests: Conflict of interest The authors declare no conflict of interest., (Copyright © 2021. Published by Elsevier B.V.)

In October 2020, a highly pathogenic avian influenza (HPAI) subtype H5N8 virus was identified from a fecal sample of a wild mandarin duck ( Aix galericulata ) in South Korea. We sequenced all eight genome segments of the virus, designated as A/Mandarin duck/Korea/K20-551-4/2020(H5N8), and conducted genetic characterization and comparative phylogenetic analysis to track its origin. Genome sequencing and phylogenetic analysis show that the hemagglutinin gene belongs to H5 clade 2.3.4.4 subgroup B. All genes share high levels of nucleotide identity with H5N8 HPAI viruses identified from Europe during early 2020. Enhanced active surveillance in wild and domestic birds is needed to monitor the introduction and spread of HPAI via wild birds and to inform the design of improved prevention and control strategies.

Korea is located within the East Asian-Australian flyway of wild migratory birds during the fall and winter seasons. Consequently, the likelihood of introduction of numerous subtypes and pathotypes of the Avian influenza (AI) virus to Korea has been thought to be very high. In the current study, we surveyed wild bird feces for the presence of AI virus that had been introduced to Korea between September 2017 and February 2018. To identify and characterize the AI virus, we employed commonly used methods, namely, virus isolation (VI) via egg inoculation, real-time reverse transcription-polymerase chain reaction (rRT-PCR), conventional RT-PCR (cRT-PCR) and a newly developed next generation sequencing (NGS) approach. In this study, 124 out of 11,145 fresh samples of wild migratory birds tested were rRT-PCR positive; only 52.0% of VI positive samples were determined as positive by rRT-PCR from fecal supernatant. Fifty AI virus specimens were isolated from fresh fecal samples and typed. The cRT-PCR subtyping results mostly coincided with the NGS results, although NGS detected the presence of 11 HA genes and four NA genes that were not detected by cRT-PCR. NGS analysis confirmed that 12% of the identified viruses were mixed-subtypes which were not detected by cRT-PCR. Prevention of the occurrence of AI virus requires a workflow for rapid and accurate virus detection and verification. However, conventional methods of detection have some limitations. Therefore, different methods should be combined for optimal surveillance, and further studies are needed in aspect of the introduction and application of new methods such as NGS., Competing Interests: The authors declare no conflicts of interest., (© 2019 The Korean Society of Veterinary Science.)

Porcine epidemic diarrhea virus (PEDV) infects pigs and causes an enteric disease that is characterized by vomiting and watery diarrhea. PEDV outbreaks have a tremendous financial impact on the worldwide pork industry. In South Korea, the incidence of PEDV has continued despite nationwide use of attenuated and inactivated vaccines, raising questions regarding the current vaccines' efficacy and the need for new vaccine development. In the present study, we isolated a new Korean PEDV epidemic strain, PED-CUP-B2014, in Vero cells. Phylogenetic analysis of the spike gene demonstrated that the PED-CUP-B2014 belongs in genogroup G2b and is close to PEDVs currently circulating in many countries including the United States, and is distinct from many current vaccine strains. Upon serial passages into Vero cells, PED-CUP-B2014 adapted to Vero cells, which was evidenced as higher virus growth in Vero cells and confirmed lower virulence in suckling piglets. The administration of the inactivated 65-passaged PED-CUP-B2014 to sows greatly increased the survival rate of their offspring and significantly reduced diarrhea severity after PEDV challenge. Higher serum/colostrum PEDV-specific antibodies and higher neutralizing titers were shown in sows vaccinated with PED-CUP-B2014 compared to unvaccinated sows or sows administered commercial PEDV vaccine. Altogether, our data demonstrated that the newly isolated PEDV strain conferred critical passive immune protection to pigs against epidemic PEDV infection., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Local lymph node assay: 5-bromo-2-deoxyuridine-flow cytometry method (LLNA: BrdU-FCM) is a modified non-radioisotopic technique with the additional advantages of accommodating multiple endpoints with the introduction of FCM, and refinement and reduction of animal use by using a sophisticated prescreening scheme. Reliability and accuracy of the LLNA: BrdU-FCM was determined according to OECD Test Guideline (TG) No. 429 (Skin Sensitization: Local Lymph Node Assay) performance standards (PS), with the participation of four laboratories. Transferability was demonstrated through successfully producing stimulation index (SI) values for 25% hexyl cinnamic aldehyde (HCA) consistently greater than 3, a predetermined threshold, by all participating laboratories. Within- and between-laboratory reproducibility was shown using HCA and 2,4-dinitrochlorobenzene, in which EC2.7 values (the estimated concentrations eliciting an SI of 2.7, the threshold for LLNA: BrdU-FCM) fell consistently within the acceptance ranges, 0.025-0.1% and 5-20%, respectively. Predictive capacity was tested using the final protocol version 1.3 for the 18 reference chemicals listed in OECD TG 429, of which results showed 84.6% sensitivity, 100% specificity, and 88.9% accuracy compared with the original LLNA. The data presented are considered to meet the performance criteria for the PS, and its predictive capacity was also sufficiently validated., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The results of our DNA analysis showed that there was 100% homology of the VP28 and VP19 genes of white spot syndrome virus (WSSV) among the samples collected from different shrimp farms in Korea. Comparing with an earlier isolated Korean strain, Korea01, the genes nucleotide sequences had only a single base difference which was observed in both VP19 and VP28. This resulted in a single amino acid substitution at position 40 of the latter. This implies that a single genetic strain of WSSV has been circulating in Korea and that its mutation rate is very low. In comparison with known sequences of VP19 and VP28 genes of WSSV isolates from other countries, the Korean strains had more than 99% sequence homology with those in gene and protein. Based on our sequence analysis of VP19 and VP28 of WSSV from various shrimp farms in Korea, the WSSV strains circulating in the region were genetically identical and similar to the strain identified two years ago. In addition, the Korean strain had close genetic identity with strains circulating in other Asian countries as well as other continents.