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This study identifies the stigma experienced by 12 bereaved parents 2 and 5 years after losing a child in the Sewol ferry disaster in South Korea. Using thematic analysis, we categorized the experience of stigma into two components based on Corrigan and Kosyluk's social cognitive model of stigma: public stigma and self-stigma, and each was analyzed into three types of stigma: stereotype, prejudice, and discrimination. We identified four additional factors related to stigma mitigation. The potential implications for characterizing the experiences of bereaved parents, particularly those facing stigma, are discussed in light of these findings in the longitudinal perspective., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

We report the first North American origin class I avian orthoavulavirus 1 (AOAV-1) isolated from a faecal dropping of wild Eurasian teal ( Anas crecca ) in South Korea. Whole genome sequencing and comparative phylogenetic analysis revealed that the AOAV-1/Eurasian teal/South Korea/KU1405-3/2017 virus belongs to the sub-genotype 1.2 of class I AOAV-1. Phylogenetic analysis suggested multiple introductions of the North American sub-genotype 1.2 viruses into Asia and its establishment in the wild bird population in East Asia since May 2011. These results provide information on the epidemiology of AOAV-1, particularly the role of migratory wild birds in exchanging viruses between the Eurasian and North American continents. Enhanced genomic surveillance is required to improve our understanding on the evolution and transmission dynamics of AOAV-1 in wild birds.

We isolated novel reassortant avian influenza A(H5N6) viruses containing genes from clade 2.3.4.4b H5N1 virus and low pathogenicity avian influenza viruses in carcasses of whooper swans and bean geese in South Korea during December 2023. Neuraminidase gene was from a clade 2.3.4.4b H5N6 virus infecting poultry and humans in China.

This study investigated the nitrate dual isotopic compositions (δ 15 N NO3 and δ 18 O NO3 ) of water samples to trace nitrate sources in Lake Sihwa, which encompasses various land-use types (e.g., urban, industry, wetland, and agriculture). The biogeochemical interactions of anthropogenic nitrogen sources (e.g., soil, road dust, and septic water) were also evaluated through multiple pathways from terrestrial boundaries to the water column. Based on increased concentrations of dissolved total nitrogen (DTN; 3.1 ± 1.6 mg/L) after typhoon, the variation of element stoichiometry (N:P:Si) in this system shifted to the relatively N-rich conditions (DIN/DIP; 14.1 ± 8.1, DIN/DSi; 1.4 ± 1.8), potentially triggering the occurrence of harmful algal blooms. Furthermore, discriminative isotopic compositions (δ 15 N NO3 ; 4.0 ± 2.1 ‰, δ 18 O NO3 ; 6.1 ± 4.3 ‰) after the typhoon suggested the increased DTN input of anthropogenic origins within Lake Sihwa would be mainly transported from urban sources (76 ± 9 %). Consequently, the isotopic-based approach may be useful for effective water quality management under increased anthropogenic activities near aquatic systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

We isolated a high pathogenicity avian influenza (HPAI) virus from a common pochard ( Aythya ferina ) that was being attacked by a bird of prey in South Korea in December 2020. Genetic analyses indicated that the isolate was closely related to the clade 2.3.4.4b H5N8 HPAI viruses found in South Korea and Japan during the winter season of 2020-2021. The histopathological examination revealed multifocal necrotizing inflammation in the liver, kidney, and spleen. Viral antigens were detected in the liver, kidney, spleen, trachea, intestine, and pancreas, indicating the HPAI virus caused a systemic infection. The presence of immunoreactivity for the viral antigen was observed in the cells involved in multifocal necrotic inflammation. Notably, epitheliotropic-positive patterns were identified in the epithelial cells of the trachea, mucosal epithelium of the intestine, and ductular epithelium of the pancreas. These findings provide direct evidence supporting the possibility of HPAI transmission from infected waterfowl to predators.

Infectious bronchitis virus (IBV), an avian coronavirus, has caused considerable damage to the poultry industry. In Korea, indigenous KM91-like and newly introduced QX-like lineages belonging to the GI-19 lineage have been prevalent despite constant vaccination. In this study, complete genome sequences of 23 IBV isolates in Korea from 2010 to 2020 were obtained using next-generation sequencing, and their phylogenetic relationship and recombination events were analyzed. Phylogenetic analysis based on the S1 gene showed that all isolates belonged to the GI-19 lineage and were divided into five subgroups (KM91-like, K40/09-like, and QX-like II to IV). Among the 23 isolates, 14 recombinants were found, including frequent recombination between KM91-like and QX-like strains. In addition, it was observed that other lineages, such as GI-1, GI-13, and GI-16, were involved in recombination. Most recombination breakpoints were detected in the ORF1ab gene, particularly nsp3. However, when considering the size of each genome, recombination occurred more frequently in the 3a, E and 5a genes. Taken together, genetic recombination frequently occurred throughout the entire genome between various IBV strains in Korea, including live attenuated vaccine strain. Our study suggests the necessity of further research on the contribution of recombination of genomes outside the spike region to the biological characteristics of IBV., Competing Interests: Declaration of competing interest None., (Copyright © 2023. Published by Elsevier B.V.)

Background: There is a lack of studies about which factors affect the quality of life (QoL) in children with atopic dermatitis (AD), although it is well known that AD has considerably negative effects on their QoL. Objective: This study aimed to measure the QoL in children with AD and identify the factors that affect their QoL. Methods: A questionnaire derived from the Children's Dermatology Life Quality Index (CDLQI) was used to measure QoL. Family history, allergic comorbidities, exacerbation-related factors, time of exacerbation, and previous and current treatment were also evaluated. The total immunoglobulin E (IgE) level and specific IgE sensitization were determined by the multiple allergen simultaneous test, allergy test, or skin-prick test. AD severity was categorized into mild, moderate, and severe based on treatments. Results: In total, 254 children (46.4 months, 53% boys) from seven hospitals completed the survey. The mean CDLQI score was 7.2 ± 5.5 (total score range of 0-30). The respondents were divided into three groups according to their QoL score distribution, with 0 - 4 points (n = 84), 5 - 9 points (n = 90), and ≥10 points (n = 80) representing good, fair, and poor QoL, respectively. The more severe AD showed the higher CDLQI score significantly (p = 0.001). Compared with other groups, children with poor QoL were more sensitized to inhalant allergens (odds ratio [OR] 1.29 [95% confidence interval {CI}], 1.03 - 1.62) and had more exacerbating factors (OR 1.26 [95% CI, 1.04 - 1.54]), which included inhalation allergen-related exacerbating factors (OR 2.54 [95% CI, 1.23 - 5.23), even after adjusting for age, total IgE, body mass index, severity, and use of moisturizer. The concordance between animal sensitization and an exacerbating factor, including dog and cat, was fair, with 0.39 κ and 0.85 accuracy. Conclusion: This study showed that impaired QoL in children with AD is associated with inhalant allergen sensitization and inhalant allergen-related exacerbation factors. Especially, dog and cat sensitization was a significant exacerbating factor. The inhalation-related exacerbation factors, including animal allergens, might be addressed to improve AD management in children.

During October 2022-March 2023, highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b virus caused outbreaks in South Korea, including 174 cases in wild birds. To understand the origin and role of wild birds in the evolution and spread of HPAI viruses, we sequenced 113 HPAI isolates from wild birds and performed phylogenetic analysis. We identified 16 different genotypes, indicating extensive genetic reassortment with viruses in wild birds. Phylodynamic analysis showed that the viruses were most likely introduced to the southern Gyeonggi-do/northern Chungcheongnam-do area through whooper swans (Cygnus cygnus) and spread southward. Cross-species transmission occurred between various wild bird species, including waterfowl and raptors, resulting in the persistence of HPAI in wild bird populations and further geographic spread as these birds migrated throughout South Korea. Enhanced genomic surveillance was an integral part of the HPAI outbreak response, aiding in timely understanding of the origin, evolution, and spread of the virus.

The potential roles of temperature and phytoplankton in nutrient cycling throughout the water column were investigated nearby aquaculture farms. Using the convergent cross mapping (CCM), we examined the relative strength of phytoplankton and temperature effects on nutrients. High δ 15 N values of particulate organic matter in the inner bay were detected compared to those in the outer bay. δ 15 N values >5 ‰ throughout the bay indicate that nitrogen influxes from the aquaculture farms are the critical nitrogen source in the study region. Our CCM models revealed that temperature positively and strongly affected the potential regeneration of nutrients, associated with PO 4 3- while phytoplankton utilized nutrients as soon as available. The temperature-driven nutrient regeneration was higher in the bottom layer than that in the surface layer, indicating that temperature was a more important controlling factor in nutrient fluxes from the surface sediments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

We isolated 5 highly pathogenic avian influenza A(H5N1) clade 2.3.4.4.b viruses from wild waterfowl feces in South Korea during November 2022. Whole-genome sequencing and phylogenetic analysis revealed novel genotypes produced by reassortment with Eurasian low pathogenicity avian influenza viruses. Enhanced surveillance will be required to improve prevention and control strategies.

Background: The current study developed a predictive model for suicide ideation among South Korean (Korean) adolescents using a comprehensive set of factors across demographic, physical and mental health, academic, social, and behavioral domains. The aim of this study was to address the pressing public health concerns of adolescent suicide in Korea and the methodological limitations of suicidal research., Methods: This study used machine learning methods (decision tree, logistic regression, naive Bayes classifier) to improve the accuracy of predicting suicidal ideation and related factors among a nationally representative sample of Korean middle school students (N = 6666)., Results: Factors within all domains, including demographic characteristics, physical and mental health, and academic, social, and behavioral, were important in predicting suicidal thoughts among Korean adolescents, with mental health being the most important factor., Limitations: The predictive model of the current research does not infer causality, and there may have been some loss of information due to measurement issues., Conclusions: Study results provide insights for taking a multidimensional approach when identifying adolescents at risk of suicide, which may be used to further address their needs through intervention programs within the school setting. Considering the cultural stigma attached to disclosing suicidal ideation and behavior, the current study proposes the need for a preventive screening process based on the observation and assessment of adolescents' general characteristics and experiences in everyday life., Competing Interests: Conflict of interest The authors of “Predictors of suicide ideation among South Korean adolescents: A machine learning approach” (Hayoung Kim Donnelly, Dr. Yoonsun Han, Suna Kim, and Dr. Dong Hun Lee) have declared no conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Posttraumatic anger is a commonly reported emotion among people who have experienced traumatic events. The current study aimed to demonstrate the reliability and validity of the South Korean version of the DAR-5 (DAR-5-K). The DAR-5 is a single scale with 5 items which measures posttraumatic anger. The DAR-5 is composed of five items that measure anger frequency, intensity, duration, aggression, and its interference with social relations., Methods: Data were collected from 814 South Korean adults who had experienced traumatic events and participated in the study and analyzed via the combination of exploratory factor analysis (n = 405) and confirmatory factor analysis (n = 409)., Results: Results supported the one-factor structure, as reported in previous validation studies. The scale demonstrated robust internal reliability and concurrent validity with measures of posttraumatic stress disorder (PTSD) symptoms, depression, anxiety, and self-esteem. The DAR-5 cut-off score of 12 that was established in the original validation study successfully differentiated high from low scorers with regard to PTSD symptoms, depression, anxiety, and self-esteem., Conclusion: The results confirm that the DAR-5-K is a brief and psychometrically robust measure of anger that can be used to examine South Korean adults who have experienced traumatic events., (© 2023. The Author(s).)

This study aims to investigate the psychometric properties, stability, and predictive validity of the PG-13-K. Two subsamples were used: the first subsample ( N  = 153), participated at Time 1 only, and the second subsample ( N  = 184) participated at both Time 1 and Time 2. At each time point, reliability, test-retest reliability, and validity were adequate, and the hypothesized two-factor model indicated good to excellent fit. Moreover, the PG-13-K was able to predict the correlation between prolonged grief disorder (PGD) and negative psychological factors. The PG-13-K is a useful and valid instrument for measuring PGD symptoms in Korean settings.

This study compared reports of parental life experiences from bereaved parents at two and five years after the death of their adolescent children due to the sinking of the Sewol Ferry in South Korea. Twelve bereaved parents (eight mothers and four fathers from eight families) were interviewed regarding the changes and stabilities they experienced over time at two time points of data collection. Twenty-eight in-depth interviews were transcribed verbatim and analyzed using qualitative content analysis. Outcomes of parental bereavement and changes in life over time may be classified into four main categories: (a) personal changes, (b) changes in perspectives, (c) changes in family relationship, and (d) changes in social relationship and work attitude. This study includes a detailed examination of the phenomenon among the bereaved parents. Discussions and implications are provided based on the results.

The threat of COVID-19 outbreak in South Korea and around the globe challenged not only physical health but also mental health, increasing the chances of disorders such as posttraumatic stress disorder (PTSD). Such pandemic situation can be referred to a traumatic event for citizens. The present study aims to examine the psychometric properties of the PTSD Checklist (PCL-5), which is named the K-COVID-related-PTSD. The scale measures PTSD symptomology in the context of the COVID-19 pandemic in South Korea. A total of 1434 South Korean citizens were included in this study. The data were statistically analyzed using SPSS 21.0 and Mplus 8.0. The results of confirmatory factor analysis demonstrated a superior fit for the seven-factor hybrid model (x 2  = 1425.445 (df = 149), CFI = 0.950, TLI = 0.937, SRMR = 0.033, RMSEA = 0.077) consisting of re-experiencing, negative affect, anxious arousal, dysphoric arousal, avoidance, anhedonia, and externalizing behaviors. Furthermore, the K-COVID-related-PTSD showed a satisfactory level of internal consistency (α = 0.793 to α = 0.939) with good convergent and discriminant validity. Finally, concurrent validity was confirmed by the significant correlations with all the negative mental health outcomes, such as PTSD symptoms, somatization, depression, anxiety, anger, negative affect, job burnout, and suicidal ideation. Overall, the current results demonstrate the K-COVID-related-PTSD is a valid scale and therefore has important implications for future pandemic-related studies., (© 2022. The Author(s).)

We report the first detection of Y280-lineage H9N2 avian influenza viruses in live bird markets in Korea during July 2020. The viruses were isolated from domestic ducks and chickens traded in three markets in two different provinces, indicating dispersal of the newly introduced viruses. Complete genome sequencing and comparative phylogenetic analyses of all eight gene segments of the viruses showed high nucleotide homology to a Y280-lineage H9N2 avian influenza virus isolated in a chicken farm in China, which belongs to one of the most prevalent H9N2 genotypes in China. Increasing human cases of the same genotype H9N2 infection in China and the mammalian specific markers present in the viruses isolated suggest potential implications for public health., (© 2021 Wiley-VCH GmbH.)

Objectives: We investigated awakening time and characteristics of awakening compared nonawakening and factors contributing to poor neurologic outcomes in out-of-hospital cardiac arrest survivors in no withdrawal of life-sustaining therapy settings., Design: Retrospective analysis of the Korean Hypothermia Network Pro registry., Setting: Multicenter ICU., Patients: Adult (≥ 18 yr) comatose out-of-hospital cardiac arrest survivors who underwent targeted temperature management at 33-36°C between October 2015 and December 2018., Interventions: None., Measurements and Main Results: We measured the time from the end of rewarming to awakening, defined as a total Glasgow Coma Scale score greater than or equal to 9 or Glasgow Coma Scale motor score equals to 6. The primary outcome was awakening time. The secondary outcome was 6-month neurologic outcomes (poor outcome: Cerebral Performance Category 3-5). Among 1,145 out-of-hospital cardiac arrest survivors, 477 patients (41.7%) regained consciousness 30 hours (6-71 hr) later, and 116 patients (24.3%) awakened late (72 hr after the end of rewarming). Young age, witnessed arrest, shockable rhythm, cardiac etiology, shorter time to return of spontaneous circulation, lower serum lactate level, absence of seizures, and multisedative requirement were associated with awakening. Of the 477 who woke up, 74 (15.5%) had poor neurologic outcomes. Older age, liver cirrhosis, nonshockable rhythm, noncardiac etiology, a higher Sequential Organ Failure Assessment score, and higher serum lactate levels were associated with poor neurologic outcomes. Late awakeners were more common in the poor than in the good neurologic outcome group (38/74 [51.4%] vs 78/403 [19.4%]; p < 0.001). The awakening time (odds ratio, 1.005; 95% CIs, 1.003-1.008) and late awakening (odds ratio, 3.194; 95% CIs, 1.776-5.746) were independently associated with poor neurologic outcomes., Conclusions: Late awakening after out-of-hospital cardiac arrest was common in no withdrawal of life-sustaining therapy settings and the probability of awakening decreased over time., Competing Interests: The authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2021 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.)

Background: Beliefs about the unacceptability of experiencing or expressing negative emotions can contribute to diverse psychological symptoms and associated with poor treatment outcomes and low treatment attempts. The Beliefs about Emotions Scale (BES) was developed to assess such beliefs based on the cognitive-behavioral models; however, no study has reported on the psychometric properties of the BES in Korea. The present study aimed to cross-culturally adapt and validate the BES for the Korean population (BES-K)., Methods: The BES-K was administered to 592 Korean adults (323 men and 269 women) aged 20-59 years. Exploratory and confirmatory factor analysis were used to assess the factor model of the scale. Pearson correlation coefficients were used to evaluate the relationships between the BES-K and other psychological measures., Results: The result showed a two-factor model of the BES-K, with Factor 1 relating to Interpersonal and Factor 2 representing Intrapersonal aspects. The scale had significant yet moderately low correlations with measures of depression, anxiety, and difficulties in emotion regulation., Conclusion: The BES-K is a useful instrument in evaluating the beliefs about emotions in the Korean population., (© 2022. The Author(s).)

Zoonotic infection with avian influenza viruses (AIVs) of subtype H7, such as H7N9 and H7N4, has raised concerns worldwide. During the winter of 2020-2021, five novel H7 low pathogenic AIVs (LPAIVs) containing different neuraminidase (NA) subtypes, including two H7N3, an H7N8, and two H7N9, were detected in wild bird feces in South Korea. Complete genome sequencing and phylogenetic analysis showed that the novel H7Nx AIVs were reassortants containing two gene segments (hemagglutinin (HA) and matrix) that were related to the zoonotic Jiangsu-Cambodian H7 viruses causing zoonotic infection and six gene segments originating from LPAIVs circulating in migratory birds in Eurasia. A genomic constellation analysis demonstrated that all H7 isolates contained a mix of gene segments from different viruses, indicating that multiple reassortment occurred. The well-known mammalian adaptive substitution (E627K and D701N) in PB2 was not detected in any of these isolates. The detection of multiple reassortant H7Nx AIVs in wild birds highlights the need for intensive surveillance in both wild birds and poultry in Eurasia.

Despite receiving a considerable amount of attention in the past, quantitative and systematic estimation of the source contributions for different organic carbons (OCs) in complex river systems is still challenging. In this study, we tested an integrated framework using field data of bulk elements and lipid biomarkers and hydrological modeling (hydrological simulation program FORTRAN, HSPF) for the quantitative estimation of OC loads along different land-use types of a watershed (Geumho River watershed in South Korea). Based on the specific source assignments identified from the lipid biomarker patterns in particulate organic carbon (POC) such as short/long chains of alkanes, fatty acids and alcohols, and coprostanol/cholesterol, spatial variations of the diagnostic lipids could be used as an indicator to discriminate between the contributions of natural (algae, bacteria, and terrestrial plants) and anthropogenic sources (fecal). Based on the integration of HSPF modeling, it was also found that various POC loads might be partially controlled by different water discharges within watersheds. With the increase in POC fluxes, the increase in fecal loads was also noticed, as reflected by the predominant lipid (especially coprostanol normalized by water discharges). As a straightforward approach, we developed a set of indices including fecal index-1, ratios of coprostanol, fatty acids, and alkanes, which strengthened the sensitivity for fecal contamination. Compared with the conventional HSPF results, the variations of these proposed indices were more influenced by the broadened watershed extents with increasing downstream distance, which provided a more accurate estimation of the quantitative contributions of POC loadings in the complex river system., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

During October 2020-January 2021, we isolated a total of 67 highly pathogenic avian influenza (HPAI) H5N8 viruses from wild birds and outbreaks in poultry in South Korea. We sequenced the isolates and performed phylogenetic analysis of complete genome sequences to determine the origin, evolution, and spread patterns of these viruses. Phylogenetic analysis of the hemagglutinin (HA) gene showed that all the isolates belong to H5 clade 2.3.4.4 subgroup B (2.3.4.4b) and form two distinct genetic clusters, G1 and G2. The cluster G1 was closely related to the 2.3.4.4b H5N8 HPAI viruses detected in Europe in early 2020, while the cluster G2 had a close genetic relationship with the 2.3.4.4b H5N8 viruses that circulated in Europe in late 2020. A total of seven distinct genotypes were identified, including five novel reassortants carrying internal genes of low pathogenic avian influenza viruses. Our Bayesian discrete trait phylodynamic analysis between host types suggests that the viruses initially disseminated from migratory waterfowl to domestic duck farms in South Korea. Subsequently, domestic duck farms most likely contributed to the transmission of HPAI viruses to chicken and minor poultry farms, highlighting the need for enhanced, high levels of biosecurity measures at domestic duck farms to effectively prevent the introduction and spread of HPAI.

Objective: To evaluate the association between diastolic blood pressure and massive transfusion in severe trauma., Method: The retrospective study was conducted at a tertiary emergency medical centre in Gwangju , Republic of Korea, and comprised data of severe trauma patients with injury severity score >15 presenting between January 2016 and December 2017. Multivariate logistic regression analysis was performed to evaluate the association between diastolic blood pressure and massive transfusion. Receiver operating characteristic curve analysis was performed to estimate the prognostic performance of diastolic blood pressure. Data was analysed using SPSS 18., Results: Of the 827 patients, 64(7.7%) underwent massive transfusion. After adjusting the confounders, diastolic blood pressure was found to be an independent factor in predicting massive transfusion (odds ratio: 0.965; 95% confidence interval: 0.956-0.975)., Conclusions: Initially low diastolic blood pressure was found to be an independent predictor for massive transfusion in severe trauma cases.

Abstract: This retrospective cohort study aimed to compare the effectiveness of conventional treatment and ultra-early application of negative pressure wound therapy (NPWT) in patients with snakebites.Patients who visited the emergency department within 24 hours after a snakebite were assigned to the non- NPWT or NPWT group. Swelling resolution time and rates of necrosis, infection, and operations were compared between the 2 groups. The Stony Brook Scar Evaluation Scale was used to measure short- and long-term wound healing results.Among the included 61 patients, the swelling resolution time was significantly shorter in the NPWT group than in non- NPWT group (P = .010). The NPWT group showed lower necrosis (4.3% versus 36.8%; P = .003) and infection (13.2% and 4.3%; P = .258) rates than the non- NPWT group. The median Stony Brook Scar Evaluation Scale scores were higher in the NPWT group than in the non- NPWT group (P< .001).These findings suggest that ultra-early application of NPWT reduces edema, promotes wound healing, and prevents necrosis in patients with snakebites., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

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.

Purpose: Specific food consumption, besides food allergy, may aggravate atopic dermatitis (AD). However, previous reports on the association between AD and food intake in adolescents are scarce. The aim of this study was to determine the relationship between AD and specific food consumption frequency in adolescents., Methods: A cross-sectional analysis using data from the Korea Youth Risk Behavior Web-based Survey 2017 was performed. The frequency of food consumption in the recent-diagnosed AD group (AD diagnosed within 12 months) compared to those in the previous-diagnosed AD (AD diagnosed more than 12 months ago) or control group were investigated., Results: A total of 53,373 participants were eligible for this study. The weighted prevalence of the recent-diagnosed AD and the previous-diagnosed AD was 7.39% and 18.00%, respectively. When compared with subjects with the previous-diagnosed AD, those with the recent-diagnosed AD were significantly more likely to frequently consume fast foods (odds ratio OR 1.405; 95% CI 1.150-1.717), energy drinks (OR 1.457; 95% CI 1.175-1.807), or convenience food (OR 1.304; 95% CI 1.138-1.495). Patients of the recent-diagnosed AD were significantly more likely to frequently consume fast foods (OR 1.374; 95% CI 1.155-1.634) than the control group. The differences in the frequency of specific food consumption among groups were more pronounced in high school students than in middle school students., Conclusions: Frequent intake of fast foods, energy drinks, and convenience food was related to the recent-diagnosed AD in adolescents. Prospective cohort and interventional studies are needed to identify causal relationships.

The aim of this study was to provide empirical descriptions of responses to the death of a sibling to the sinking of the Sewol ferry in South Korea. 16 bereaved parents are interviewed regarding their surviving children's grief responses at approximately 2 years after the death. The surviving siblings described by the bereaved parents are 14 in total, including 8 teens in their 10s and 4 young adults in their 20s. Interviews were transcribed verbatim and analyzed using a qualitative content analysis method. The following themes emerged: (a) negative behavioral changes, (b) expressions of grief, (c) change in relationship with parents, (d) school adjustment problems, and (e) social changes. Unique aspects of the grief responses among the surviving siblings in this study are noted. Discussions and implications are provided based on the results.

Purpose: Since January 2016, emergency medical centers in South Korea have used the Korean Triage and Acuity Scale (KTAS) as the initial triage tool for all patients, including trauma patients, who visited the emergency department (ED). This present study aimed to assess the validity of the KTAS for predicting 30-day mortality due to severe trauma., Methods: This retrospective study included patients with severe trauma (injury severity score ≥ 16) from January 2016 to December 2017. Using KTAS, all patients were triaged as levels 1, 2, 3, and 4 by triage nurses. The primary outcome was 30-day mortality, and the secondary outcome was disposition at the ED. Disposition at the ED included admission to the general ward, intensive care unit, or operation room or death in the ED., Results: Of the 827 included patients, 30-day mortality was observed in 14.9% (n = 123) of patients. Mortality was observed in 52.5% (n = 42), 15.5% (n = 69), 4.1% (n = 12), and 0.0% (n = 0) of patients in levels 1, 2, 3, and 4, respectively. The Cox proportional hazard regression analysis showed that compared to level 3, level 1 [hazard ratio (HR) 4.868; 95% confidence interval (CI) 2.341-10.119] and level 2 (HR 2.070; 95% CI 1.083-3.956) were independently associated with 30-day mortality. Patients with lower KTAS levels were more likely to be admitted to the operation room and were more likely to die in the ED., Conclusion: Lower KTAS levels were associated with higher 30-day mortality due to severe trauma. KTAS shows adequate validity for predicting 30-day mortality from severe trauma.

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 5.3% of AIV isolations). In 2015, one LPAI H5N3 strain was isolated on a duck farm. Phylogenetic analysis revealed that the hemagglutinin (HA) gene of H5 isolates belonged to the Eurasian lineage, classified into three subgroups (HA-II, HA-III, and HA-IV). The H5 LPAIVs of the HA-III and HA-IV subgroups appeared in 2015 and 2017 in unusually high proportions (13.1% and 14.4%, respectively). In gene-constellation analysis, H5 LPAIVs isolated from 2015 to 2017 constituted ≥ 35 distinct genotypes, representing high levels of genetic diversity. Representative strains of three HA subgroups replicated restrictively in specific-pathogen-free chickens. Among the 11 isolates that were tested, 10 infected and replicated in mice without prior adaptation. The frequency of recent H5 LPAIV isolates with high genetic diversity indicates the importance of continued surveillance in both wild birds and poultry to monitor genetic and pathobiological changes.

Background: There are few studies that directly compared different interventions to improve medical students' clinical reasoning for dermatologic conditions., Objective: To investigate the effectiveness of adding practice with reflection and immediate feedback on traditional dermatology electives in improving medical students' ability in evaluating skin lesions., Methods: The participants were fourth-year medical students of Seoul National University College of Medicine, Korea, who were enrolled to take a 2-week dermatology elective course (n = 87). Students were assigned to one of the three educational interventions: 2-h training involving 10 written clinical cases (experimental); 1-h lecture and 1-h outpatient clinic (lecture); and 2-h outpatient clinic (no intervention). Before and at the end of rotation, diagnostic accuracy was estimated using 20 written clinical cases with photographs (10 novel cases presented in diagnostic training [training set], 10 cases with diagnoses not included in training [control set])., Results: There was a significant interaction effect of intervention×set×time. A post hoc analysis indicated that the students in the experimental group outperformed students in the other two groups only in the training set of the final tests; after completing the 2-week rotation, for the training set, the mean score was higher in the experimental group (7.5 ± 1.3) than in the lecture (5.7 ± 1.6) and no intervention (5.6 ± 1.3) groups, producing an effect size of 1.2 standard deviation (SD) and 1.5 SD, respectively., Conclusion: Practicing written clinical cases with reflection and feedback is superior to a lecture-based approach and yields additional benefits to a dermatology elective, thereby enhancing medical students' ability to accurately diagnose skin lesions., Trial Registration: ClinicalTrials.gov, NCT03472001. Registered 21 March 2018.

Live bird markets (LBMs) in Korea have been recognized as a reservoir, amplifier, and source of avian influenza viruses (AIVs); however, little was known about the role of LBMs in the epidemiology of AIVs in Korea until recently. Through 10 years of surveillance (2006-2016) we have isolated and sequenced H9N2 viruses in Korean LBMs. To understand how H9N2 evolves and spreads in Korea, a statistical Bayesian phylogenetic model was used. Phylogenetic analysis suggests that three separate introductions of progenitor gene pools, Korean domestic duck-origin and two wild aquatic bird-origin AIVs, contributed to the generation of the five genotypes of H9N2 viruses in Korea. Phylogenetic reconstruction of ecological states infer that the LBMs are where chickens become infected with the virus, with domestic ducks playing a major role in the transmission and evolution of the H9N2 viruses. Three increases in the genetic diversity of H9N2 viruses were observed and coincided with transitions in host species and the locations (domestic farm, LBM, slaughterhouse, and wild aquatic bird habitat) where the viruses were isolated, accompanying genetic reassortment. Following the introduction of a wild aquatic bird-origin AIVs in 2008, six genes of the Korean lineage H9N2 virus were replaced with genes originating from wild aquatic birds, and viruses with this new genotype became predominant in Korean LBMs.

The H5N8 highly pathogenic avian influenza viruses (HPAIVs) belonging to clade 2.3.4.4 spread from Eastern China to Korea in 2014 and caused outbreaks in domestic poultry until 2016. To understand how H5N8 HPAIVs spread at host species level in Korea during 2014-2016, a Bayesian phylogenetic analysis was used for ancestral state reconstruction and estimation of the host transition dynamics between wild waterfowl, domestic ducks and chickens. Our data support that H5N8 HPAIV most likely transmitted from wild waterfowl to domestic ducks, and then maintained in domestic ducks followed by dispersal of HPAIV from domestic ducks to chickens, suggesting domestic duck population plays a central role in the maintenance, amplification and spread of wild HPAIV to terrestrial poultry in Korea., (© 2019 Blackwell Verlag GmbH.)

Since 2017, clade 2.3.4.4b H5N6 highly pathogenic avian influenza viruses (HPAIVs) have been detected over a broad geographic region, including Eurasia. These viruses have evolved through reassortment with Eurasian low pathogenic avian influenza viruses (LPAIVs), resulting in multiple genotypes. Here, we sequenced the full-length genome of 15 H5N6 HPAIVs collected from wild birds and poultry farms in South Korea from January to March 2018. A comparative phylogenetic analysis was then conducted. Three distinct genotypes were identified in South Korea during 2017/2018, including a novel reassortant genotype, H214. The novel reassortant H5N6 viruses isolated in this study possessed PB2, PA, and NP gene segments of Eurasian LPAIV on a genetic backbone of the H35-like genotype, which was identified in Korea and the Netherlands during 2017. Bayesian molecular clock analysis suggested that the novel reassortant viruses were generated most likely during the fall migration/wintering season of migratory waterfowl in 2017. Considering the continued emergence and spread of clade 2.3.4.4 HPAIV, enhanced surveillance of wild waterfowl is needed for early detection of HPAIV incursions., Competing Interests: Declaration of Competing Interest None, (Copyright © 2019 Elsevier B.V. All rights reserved.)

The aim of this study was to identify the outcomes of parental bereavement and the changes in life experience that follow the traumatic death of a teenage child. The results of the study are aimed to assist counselors and educators who work with themes of grief and loss. From 17 in-depth interviews from parents bereaved by the Sewol ferry disaster of 2014 in South Korea, three main categories were found to capture the reality for parents after the sudden and traumatic death of a teenage child: (a) personal changes, (b) changes in close relationships, and (c) changes in social life. Recommendations for future research and potential implications were discussed.

The incidence of herpes zoster (HZ) is mainly affected by age. Various comorbidities could influence the risk of HZ, but a general guideline for evaluating their effect on HZ is lacking. The purpose of this study was to determine whether the Charlson comorbidity index (CCI) is useful in evaluating the risk of HZ in the general population. This retrospective cohort study analyzed data from 1 016 580 random multistage representative samples in Korea, recorded from 2004 to 2013 in the South Korean National Health Insurance Service-National Sample Cohort database. We calculated the baseline CCI score of comorbidities and compared the hazard ratio (HR) of HZ according to the calculated CCI scores. A total of 340 124 eligible subjects aged 40-79 years and 35 874 HZ patients were identified. After adjustment of age, sex and income, the HR of HZ and odds ratio of postherpetic neuralgia in the CCI score of 1 or more group was found to be significantly higher than that of the CCI score 0 group. Compared with the 60s age group with a CCI score of 0, the 50s age group with a CCI score of 1 had a higher risk of HZ, and the 40s age group with a CCI score of 3 or more had a similar risk of HZ. Scoring systems of comorbidities such as the CCI could be useful in identifying the high-risk group for HZ, especially among the 40-59-year age group. Further studies are required to establish the usage of a HZ-specific comorbidity scoring system in a large multinational population., (© 2019 Japanese Dermatological Association.)

This study aims to identify parenting experiences after the death of a child. Using interpretive phenomenological analysis, we mapped the experiences of 16 parents with school-aged surviving children after the death of their sibling to the 2014 Sewol ferry disaster in South Korea. Interviews illuminate five master themes of parenting surviving children following a child's death: (a) parental anxiety, (b) conflicts and obstacles in the parent-child relationship, (c) changes in parenting style, (d) striving to support children's grief, and (e) seeking outside help for parenting. Implications for supporting grieving parents and their children are discussed in light of the findings.

Background and Objective: Many laser devices have been developed over the past decades for various skin conditions. However, variations in the technical skill of physicians for laser skin treatment delivery have not yet been evaluated. This study evaluates the differences in omission and overlap percentages during simulated laser hair removal treatments among physicians at two clinics., Materials and Methods: A laser beam detection kit was developed to record and collect laser irradiation from a diode laser device. Eight physicians (primary private clinic 4, tertiary referral hospital 4) were recruited to perform 80 trials of laser delivery simulation. The simulation process was captured in video frames by a camera built inside of the detection kit. The laser distribution map was reconstructed, and each physician's performance result was determined by a computer calculation., Results: Various assumption tests showed that each physician had different laser delivery skills. Four physicians from clinic A had an average omission rate of 13.4%, and four physicians from clinic B had an average omission rate of 19.7%. Regarding the average overlap rate of the two clinics, clinic A had a higher rate than clinic B (26.1% vs. 14.6%)., Conclusions: The study's findings confirmed the differences of the technical skills among the physicians and between the two clinics. The proposed computer-assisted evaluation of technical skill is useful for assessing physicians' performance during laser skin treatments.

Aim of the Study: Studies examining associations between time to target temperature and outcomes in cardiac arrest patients who underwent targeted temperature management (TTM) have shown inconsistent results. We examined these associations separately for time from restoration of spontaneous circulation to TTM initiation (pre-induction time) and time from TTM initiation to target temperature (induction time). Furthermore, we examined whether critical time thresholds exist if there is an association., Methods: This was a single-centre retrospective observational study including adult cardiac arrest patients treated with TTM from 2008 to 2015. We tested the associations of pre-induction time and induction time with outcomes at hospital discharge using multivariate logistic regression analysis. We then performed additional multivariate analyses, each with the significant timing variable at different binary cutoffs., Results: A total of 515 patients were analysed. At hospital discharge, 357 patients (69.3%) were alive, of whom 161 (31.3%) had a favourable neurologic outcome. In multivariate analysis, a shorter pre-induction time was independently associated with a favourable neurologic outcome (odds ratio [OR], 1.110; 95% confidence interval [CI], 1.025-1.202), whereas the induction time was not (OR, 0.954; 95% CI, 0.852-1.067). We found two pre-induction time thresholds (120 and 360min) that were associated with neurologic outcome., Conclusion: We found that a shorter pre-induction time was independently associated with a favorable neurologic outcome at hospital discharge, whereas induction time was not. We also found two time thresholds at 120 and 360min, after which initiation of cooling was associated with a worse neurologic outcome., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Purpose: Obesity is a well-known risk factor in various health conditions. We analyzed the association between obesity and clinical outcomes, and its effect on targeted temperature management (TTM) practice for cardiac arrest survivors by calculating and classifying their body mass indexes (BMIs)., Methods: We conducted a retrospective data analysis of adult comatose cardiac arrest survivors treated with TTM from 2008 to 2015. BMI was calculated and the cohort was divided into four categories based on the cut-off values of 18.5, 23.0, and 27.5kgm -2 . The primary outcome was six-month mortality and the secondary outcomes were neurologic outcome at hospital discharge, cooling rate, and rewarming rate., Results: The study included 468 patients. Poor neurologic outcome at discharge and six-month mortality were reported in 311 (66.5%) and 271 (57.9%) patients, respectively. A multivariate logistic analysis showed that an overweight compared to normal BMI was associated with lower probability of six-month mortality (odds ratio [OR], 0.481; 95% confidence interval [CI], 0.274-0.846; p=0.011) and poor neurologic outcome at discharge (OR, 0.482; 95% CI, 0.258-0.903; p=0.023). BMI correlated with cooling rate (B, -0.073; 95% CI, -0.108 to -0.039; p<0.001), but had no association with rewarming rate (B, 0.003; 95% CI, -0.001-0.008; p=0.058)., Conclusion: Overweight BMI compared to normal BMI classification was found to be associated with lower six-month mortality and poor neurologic outcome at discharge in cardiac arrest survivors treated with TTM. Higher BMI correlated with a slower induction rate., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Porcine epidemic diarrhea virus (PEDV), a member of the Coronaviridae family, is an enveloped, positive-sense, single-stranded RNA virus, which causes severe diarrhea and dehydration in suckling pigs. We detected three PEDV strains from ten small intestine samples from piglets with acute diarrhea and we determined the complete genome sequences of the reemerging Korean PEDV field isolates, except for the noncoding regions from both ends. The complete genome sequences of the strains were identical or almost identical (one synonymous single-nucleotide polymorphism (SNP) in the ORF1a/1b genomic sequence). Interestingly, comparative genome analysis of recent Korean PEDV isolates and other strains revealed that the complete genome sequences of recent Korean strains were almost identical (99.9%) to those of the US PEDV strains isolated in 2013. These results suggest that the three reemerging Korean strains are distinct from previous endemic Korean PEDV strains and has been recently introduced into Korea from oversea with high likelihood., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In 2011, we isolated a natural recombinant H9N2 avian influenza virus from fecal droppings of bean goose (Anser fabalis) in Korea. Phylogenetic analyses showed that the A/bean goose/Korea/220/2011(H9N2) isolate is a reassortant of Eurasian and North American lineages of avian influenza virus. In addition, the complete genome sequence, including all 8 gene segments, was associated with Chinese H9N2 viruses isolated from wild birds in the Hunan East Dongting Lake National Nature Reserve. These data provide direct evidence for the exchange of avian influenza viruses between Korea and China via wild birds., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The purpose of this study was to investigate the distribution of Salmonella species in an integrated broiler supply chain in Korea. A total of 1,214 samples from various steps of an integrated broiler production company including broiler breeder farms, broiler farms, broiler trucks, slaughterhouse, and retail chicken meats were collected and investigated. Salmonella was detected in 195 of the samples. The highest prevalence of Salmonella was observed in broiler transporting trucks (71.43%), followed by the slaughterhouse (63.89%) and broiler farms (16.05%). Salmonella Hadar was the most frequently isolated serotype (83.08%). All Salmonella Hadar isolates investigated in this study with pulsed-field gel electrophoresis showed the same XbaI pulsed-field gel electrophoresis pulsotype.

This report confirms a recent outbreak of a Leucocytozoon caulleryi infection in a commercial broiler breeder flock in South Korea. Seven, 18-day-old broiler breeders (Gallus gallus) were necropsied following a history of depression, sudden death, and subcutaneous hemorrhages. On necropsy, subcutaneous hemorrhages were identified in the wings and legs, pectoral and thigh muscles, thymus, epicardium, pancreas, and kidneys. On histopathology, there were numerous schizonts and merozoits of a Leucocytozoon sp. noted in the heart, spleen, liver, kidneys, thymus, and bursa of Fabricius. Molecular analysis of the mitochondrial cytochrome oxidase b confirmed that the causative agent was Leucocytozoon caulleryi. Although L. caulleryi was diagnosed previously in South Korea, there had been no reports of L. caulleryi over the past several decades.

Infectious bronchitis virus (IBV) infections cause great economic losses to the poultry industry worldwide. IBVs continuously evolve by developing mutations in antigenic sites; therefore, an IBV vaccine that provides broad cross-protection can be a highly relevant and practical method in IBV control strategies. Although some IBV vaccine strains are known to provide protection against multiple IBV serotypes, in general commercially available IBV vaccine strains provide protection against antigenically related viruses but not distinct heterologous viruses. In the present study we characterized the Korean variant IBV K40/09 strain with regard to its immunogenicity and protective efficacy against seven currently circulating IBV serotypes. Three-week-old specific-pathogen-free chickens were intraocularly immunized with the IBV K40/09 strain at 10(3.5) 50% egg infective dose (EID50). Three weeks after immunization all the birds were challenged with seven different strains at 10(4.5) EID50. Chickens immunized with the IBV K40/09 strain showed significantly high levels of protection against all challenge viruses at the trachea and kidney levels. Our results suggest that IBV K40/09 could be useful to ensure IBV vaccine effectiveness owing to its cross-protective ability. Therefore, the IBV K40/09 strain merits consideration as a vaccine candidate to prevent infection as well as the spread of new IBV strains and many IBV variants that have been reported worldwide.

Although oxidized low-density lipoprotein (LDL) and lysophosphatidylcholine (LPC) have been proposed as important mediators of the atherosclerosis, the long-term contribution to the risk of cardiovascular disease (CVD) in hemodialysis patients has not been evaluated. This study investigated the relation between oxidized LDL and LPC levels with long term risk of CVD. Plasma oxidized LDL and LPC levels were determined in 69 Korean hemodialysis patients as a prospective observational study for 5 yr. During the observation period, 18 cardiovascular events (26.1%) occurred including 6 deaths among the hemodialysis patients. The low LPC level group (≤ 254 µM/L, median value) had much more increased risk of CVD compared to the high LPC level group (> 254 µM/L) (P = 0.01). However, serum levels of oxidized LDL were not significantly different between groups with and without CVD. In adjusted Cox analysis, previous CVD, (hazard ratio [HR], 5.68; 95% confidence interval [CI], 1.94-16.63, P = 0.002) and low LPC level (HR, 3.45; 95% CI, 1.04-11.42, P = 0.04) were significant independent risk factors for development of CVD. It is suggested that low LPC, but not oxidized LDL, is associated with increased risk of CVD among a group of Korean hemodialysis patients.

We compared the genetic and biologic characteristics of 35 influenza viruses of different epidemiological backgrounds in Korea, including H3N2 canine influenza virus (CIV). Phylogenetic analysis revealed that chicken adapted H9N2 viruses (A/chicken/Korea/96006/96 [CK/Kor/96006-like]) have acquired aquatic avian gene segments through reassortment, and these reassorted H9N2 viruses were more frequently detected from minor poultry species than from industrial poultry. Conversely, gene segments from CK/Kor/96006-like viruses were also detected in most of the viruses from domestic ducks. Interestingly, domestic ducks, rather than wild aquatic birds, harbored close relatives of all eight gene segments of H3N2 CIV, which preferred binding to avian receptors. Therefore, bidirectional virus transmission events are assumed to have occurred between land-based poultry and aquatic poultry, in particular within the non-industrial poultry system. These events have contributed to the generation of a novel reassortant, H3N2 CIV. To prevent generating other reassortants capable of interspecies transmission, gene movements in the non-industrial poultry systems should be clarified and managed., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Newcastle disease virus (NDV) has a worldwide distribution and is often carried by wild ducks, which may represent one of the natural reservoirs. However, the epidemiological relatedness of NDV between wild ducks and domestic poultry is unclear. A total of 14 isolates were obtained from 8439 samples from live bird markets (LBMs) and wild bird populations in Korea during from 2007 to 2010. These isolates were characterized genetically and phylogenetic analysis was conducted to investigate the relatedness between isolates from wild birds, LBM and poultry farms. In phylogenetic analysis, all 14 isolates belonged to genotype I virus within class II. Of these, nine isolates from wild birds were most closely related to the Aomori-like cluster. The five LBM isolates were most closely related to the V4-like cluster. All isolates in this study were closely related to isolates from domestic duck farms in Korea and Chinese LBM isolates. The results indicate that NDV exchange occurs between wild birds, poultry farms, LBMs and neighboring countries. Enhanced NDV surveillance is required to monitor the introduction of variant NDV in consequence of evolution in LBMs and to investigate NDV epidemiology in various species of putative hosts., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: Empathy is an important element of professionalism in medicine. Thus, evaluation and enhancement empathy in physicians is important, regardless of geographical boundaries., Aim: This study was designed to evaluate the psychometrics of a Korean version of the Jefferson Scale of Physician Empathy (JSPE) among Korean physicians., Methods: The Korean version of JSPE was completed by 229 physicians in Korea., Results: Item-total score correlations were all positive and statistically significant. Cronbach's coefficient alpha was 0.84. The mean score was 98.2 (SD = 12.0), which was lower than that reported for American and Italian physicians. The emerged factor structure of the translated version was somewhat similar to that reported for American physicians, although the order was different. Significant differences in the mean empathy scores were observed between men and women and among physicians in different specialties., Conclusion: Our findings provide evidence in support of reliability and construct validity of the Korean version of JSPE for assessing empathy among Korean physicians. The disparity between Korean physicians and physicians from other countries may be explained by differences in the culture of medical education and medical practice. It suggests an exploration of cross-cultural differences in physician empathy.

Since 2007, 55 adenovirus strains have been isolated from commercial chicken flocks in Korea and have been identified and the pathogenicity of these isolates was confirmed in specific-pathogen-free chickens of different age. Based on sequencing analysis of the hexon gene, 55 FAdV isolates were genetically related to the IBH-2A strain of FAdV3 (4 isolates, 99.2% to 100%), the KR5 strain of FAdV4 (22 isolates, 97.9% to 99.2%), the 764 strain of FAdV9 (11 isolates, 99.1% to 99.3%), and the 1047 strain of FAdV11 (18 isolates, > 99%). Experimental infections with four serotypes of FAdV resulted in high mortality of 18-day-old chicken embryos and 1-day-old chicks with marked liver necrosis similar to those observed in the natural outbreaks. Notably, specific hydropericardium was observed in chicks challenged with the K531 strain (serotype 4). However, 3-wk-old chickens challenged with FAdVs, regardless of serotype, did not show any clinical signs or mortality except histologic lesions of focal hepatocytic necrosis with mild lymphocytic infiltration. The results indicate that four FAdV serotypes (3, 4, 9, and 11) are the dominant serotypes of FAdVs in the Korea and are pathogenic enough to cause clinical disease in young chicks. The present investigation provides important information on the epidemiology and pathogenesis of FAdVs and highlights the importance of control strategies against FAdV infection in Korea.