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Simple Summary: The H9N2 subtype of avian influenza virus (AIV) was first identified in turkey flocks in Wisconsin, USA, in 1966. Since then, H9N2 AIVs have been detected in mammals, domestic poultry, and wild birds. In June 2020, a new H9N2/Y280 was discovered in Korea. Existing commercial vaccines might not be fully effective against H9N2/Y280. Since influenza viruses undergo mutations rapidly, fast and accurate vaccine production is critical to address variant strains. Consequently, this study focused on rapid and effective vaccine production techniques against H9N2/Y280. The recombinant rHVT/Y280 was successfully constructed using NHEJ-CRISPR/Cas9 gene-editing technology. rHVT/Y280 vaccination induced strong humoral immunity, providing significant protection against H9N2/Y280 strain A21-MRA-003 following a challenge of 2 × 107 50% egg infectious dose. Therefore, rHVT/Y280 is a potential candidate for a live vaccine against H9N2/Y280. Since the outbreak of the H9N2/Y439 avian influenza virus in 1996, the Korean poultry industry has incurred severe economic losses. A novel possibly zoonotic H9N2 virus from the Y280-like lineage (H9N2/Y280) has been prevalent in Korea since June 2020, posing a threat to the poultry sector. Rapid mutation of influenza viruses urges the development of effective vaccines against newly generated strains. Thus, we engineered a recombinant virus rHVT/Y280 to combat H9N2/Y280. We integrated the hemagglutinin (HA) gene of the H9N2/Y280 strain into the US2 region of the herpesvirus of turkeys (HVT) Fc126 vaccine strain, utilizing CRISPR/Cas9 gene-editing technology. The successful construction of rHVT/Y280 was confirmed by polymerase chain reaction and sequencing, followed by efficacy evaluation. Four-day-old specific pathogen-free chickens received the rHVT/Y280 vaccine and were challenged with the H9N2/Y280 strain A21-MRA-003 at 3 weeks post-vaccination. In 5 days, there were no gross lesions among the vaccinated chickens. The rHVT/Y280 vaccine induced strong humoral immunity and markedly reduced virus shedding, achieving 100% inhibition of virus recovery in the cecal tonsil and significantly lowering tissue viral load. Thus, HVT vector vaccines expressing HA can be used for protecting poultry against H9N2/Y280. The induction of humoral immunity by live vaccines is vital in such cases. In summary, the recombinant virus rHVT/Y280 is a promising vaccine candidate for the protection of chickens against the H9N2/Y280. [ABSTRACT FROM AUTHOR]

Infectious bursal disease (IBD), caused by IBD virus (IBDV), is an extremely contagious immunosuppressive disease that causes major losses for the poultry industry worldwide. Recently, the novel variant IBDV (G2d) has been highly prevalent in Korea, but the current vaccines against this very virulent IBDV have limited efficacy against this novel variant. To develop a vaccine against this variant IBDV, a recombinant virus designated rHVT-VP2 was constructed by inserting the IBDV (G2d) VP2 gene into herpesvirus of turkeys (HVT) using CRISPR/Cas9 gene-editing technology. The PCR and sequencing results obtained showed that the recombinant virus rHVT-VP2 was successfully constructed. Vaccination with rHVT-VP2 generated IBDV-specific antibodies in specific pathogen-free chickens starting from 2 weeks post-immunization. Seven days after the challenge, the autopsy results showed that the bursa atrophy rates of the rHVT-VP2, HVT, vaccine A, and positive control groups were 0%, 100%, 60%, and 100%, respectively, and the BBIX values were 1.07 ± 0.22, 0.27 ± 0.05, 0.64 ± 0.33, and 0.32 ± 0.06, respectively. These results indicate that rHVT-VP2 can provide 100% protection against a challenge with the IBDV (G2d), whereas vaccine A only provides partial protection. In conclusion, vaccination with the recombinant virus rHVT-VP2 can provide chickens with effective protection against variant IBDV (G2d). [ABSTRACT FROM AUTHOR]

Simple Summary: Wild animals can be of veterinary and public health concern due to their potential to harbor pathogens and transmit them to humans and domestic animals. Avian paramyxovirus 1 (APMV-1) is capable of infecting a wide range of avian species, leading to a broad spectrum of clinical symptoms and posing a potential risk to public health. This study represents the investigation of avian paramyxoviruses (APMVs) in wild waterfowl from Korea. In this study, 13 isolates of APMV-1 and 1 isolate of APMV-13 were obtained and their genetic characteristics of fusion gene were analyzed. We identified the wild ducks and geese likely to be infected with APMV, and our data suggest a possible intercontinental transmission of APMVs by wild waterfowl. Moreover, our study provides the first evidence for the presence of class I of APMV-1 and APMV-13 in wild waterfowl that were sampled in Korea. This finding not only adds to our understanding of the diversity of APMVs but also underscores the importance of monitoring and addressing the epidemiology of these viruses in wildlife, particularly from a One Health perspective. Avian paramyxoviruses (APMVs) are often carried by wild waterfowl, and the wild waterfowl may play an important role in the maintenance and spread of these viruses. In this study, we investigated APMVs in the population of migratory wild waterfowl from 2015 to 2021 in Korea and analyzed their genetic characteristics. Fourteen viruses were isolated and subsequently identified as APMV-1 (n = 13) and APMV-13 (n = 1). Phylogenetic analysis of the full fusion gene of 13 APMV-1 isolates showed that 10 APMV-1 isolates belonged to the class II sub-genotype I.2, which was epidemiologically linked to viruses from the Eurasian continent, and 3 viruses belonged to class I, which linked to viruses from the USA. The APMV-13 isolates from wild geese in this study were highly homology to the virus isolated from China. Sequence analysis of 14 isolates showed that all isolates had a typical lentogenic motif at the cleavage site. In summary, we identified the wild species likely to be infected with APMV and our data suggest possible intercontinental transmission of APMV by wild waterfowl. Our current study also provides the first evidence for the presence of class I of APMV-1 and APMV-13 in wild waterfowl surveyed in Korea. [ABSTRACT FROM AUTHOR]

Background: Although most epidemiological studies have been conducted using a relatively small population or subjects who had medical screenings, the present study aimed to investigate the incidence and prevalence of MASLD (formerly NAFLD) in Korea using nationwide registry data provided by the Health Insurance Review and Assessment Service (HIRA). Methods: Using nationwide medical records provided by HIRA, we analyzed the entire dataset of patients with MASL (KCD10-K76.0) and MASH (KCD10-K75.8) from 2010 to 2021 and calculated the incidence and prevalence by year, age, and gender. The prevalence and incidence rates were calculated by analyzing the HIRA data covering almost the entire population of Korea for 12 years, from 2010 to 2021, with an average population of 50,856,244 during this period. Statistical analyses included calculating confidence intervals using Ulm's formula and conducting sex- and age-specific analyses with a Cochran–Armitage test for trends. Results: The annual incidence of MASL/MASH increased significantly from 9.71/0.37 in 2010 to 13.95/5.52 per 1000 persons in 2021 (p < 0.01). The annual prevalence of MASL increased from 15.69 in 2010 to 34.23 per 1000 persons in 2021, while the annual prevalence of MASH increased from 0.49 to 9.79 per 1000 persons between 2010 and 2021 (p < 0.01). Regarding the sex-dimorphic feature of MASLD, there was a male predominance in those < 50 years old but a female predominance in those ≥ 50 years old for the incidence and prevalence of MASL and the incidence of MASH. Conclusion: The incidence of MASL increased by 3% to 4% every year, while the incidence of MASH increased 14.91-fold from 2010 to 2021. The increasing trend is noteworthy compared with previous reports. [ABSTRACT FROM AUTHOR]

This study aimed to develop prediction equations for maximum oxygen uptake (VO2max) based on non-exercise (anthropometric) and submaximal exercise (anthropometric and physiological) variables in paraplegic men with a spinal cord injury. All participants were tested on an arm ergometer using a maximal graded exercise test. Anthropometric variables such as age, height, weight, body fat, body mass index, body fat percentage, and arm muscle mass and physiological variables such as VO2, VCO2, and heart rate at 3 and 6 min of graded exercise tests were included in the multiple linear regression analysis. The prediction equations revealed the following. Regarding non-exercise variables, VO2max was correlated with age and weight (equation R = 0.771, R2 = 0.595, SEE= 3.187). Regarding submaximal variables, VO2max was correlated with weight and VO2 and VCO2 at 6 min (equation R = 0.892, R2 = 0.796, SEE = 2.309). In conclusion, our prediction equations can be used as a cardiopulmonary function evaluation tool to estimate VO2max simply and conveniently using the anthropometric and physiological characteristics of paraplegic men with spinal cord injuries. [ABSTRACT FROM AUTHOR]

Simple Summary: Due to the rapid environmental changes in the Seocheon Tidal Flat, South Korea, important staging and wintering sites of the vulnerable Far East Russin population of Swan Goose are threatened. To provide practical information for establishing protection strategies based on Swan Goose behavioral characteristics, we estimated core home range and habitat use patterns over time at the Seocheon Tidal Flat during wintering. Based on the GPS tracking data, the core home range and habitat use characteristics of the Swan Goose differed significantly between daytime and nighttime (Day: 59.9 km2, Night: 40.3 km2, on average, 100% MCP). In addition, our data indicated that Swan Goose has two important overnight resting areas in the Seocheon Tidal Flat, South Korea, namely the Janggu Bay and sand dune areas in Yubu Island. The Seocheon Tidal Flat is an important staging and wintering site for the Far East Russian population of Swan Goose (Anser cygnoides) in the East Asian–Australasian Flyway. However, rapid environmental changes for tourism in this area can threaten the survival of this vulnerable population by hindering sufficient rest and wintering; therefore, establishing protection strategies based on Swan Goose behavioral characteristics is necessary. Here, we estimated Swan Goose core home ranges and habitat use based on GPS tracking data collected at the Seocheon Tidal Flat in South Korea from 2017–2018. The home range of Swan Geese was estimated to be an area from Yubu Island in the south to Janggu Bay in the north; however, the core home range and habitat use characteristics differed significantly between daytime and nighttime (Day: 59.9 km2, Night: 40.3 km2, on average, 100% MCP). During the day (08:00–18:00), Swan Geese mostly spent time resting or feeding on tidal flats, especially those around tidal channels or paddy fields near Janggu Bay, whereas they mostly rested on sand dunes near Yubu Island along with the mudflats at Janggu Bay at night. Our results provide practical information on the habitat use of wintering Swan Geese population over time and indicate that Yubu Island is an important resting place. Hence, these results can contribute to evaluating threats to Swan Geese and establishing management and protection strategies for the Seocheon Tidal Flat, a major wintering site for the Far East Russian population of Swan Geese. [ABSTRACT FROM AUTHOR]

Simple Summary: Salmonella enterica serovar Gallinarum (S. enterica ser. Gallinarum) is a host-specific agent of fowl typhoid (FT). This is one of the most important bacterial infections in the poultry industry in both developing and developed countries, including South Korea. The use of antimicrobial drugs is the first choice for disease control. Antimicrobials, such as β-lactams, aminoglycosides, and fluoroquinolones, are frequently used to treat FT. However, the continuous use of antimicrobial drugs has led to the emergence and persistence of antimicrobial-resistant S. enterica ser. Gallinarum. In this study, we analyzed the antimicrobial susceptibility and epidemiological relationship of thirty isolates of S. enterica ser. Gallinarum isolated from poultry farms with an FT outbreak from 2013 to 2018 in South Korea. All the isolates showed a multi-drug resistant (MDR) phenotype. This study confirmed horizontal transmission and cross-contamination between farms within the same integrated poultry company or between farms belonging to different companies. The characterization of these isolates would be helpful to develop prevention and control strategies for the MDR S. enterica ser. Gallinarum infection in South Korea. Antimicrobial resistance and pulsed-field gel electrophoresis (PFGE) genotypes of collected S. enterica ser. Gallinarum isolates were investigated to examine the epidemiological relationship between field outbreak isolates of S. enterica ser. Gallinarum. Thirty S. enterica ser. Gallinarum isolates collected from poultry farms with FT outbreaks from 2013 to 2018 in South Korea were analyzed. All isolates were resistant to at least 3 of the 18 antimicrobials tested and exhibited an MDR phenotype. All isolates showed resistance to streptomycin, sulfisoxazole, and colistin. One isolate was resistant to 9 antimicrobials. The antimicrobial resistance profile, streptomycin-sulfisoxazole-colistin-nalidixic acid-ciprofloxacin-gentamicin (18/30, 60.0%), was the most prevalent. PFGE types were classified into 10 groups with a 100% correlation cutoff in dendrograms for 30 field isolates. The dominant PFGE types were 1 (8/30, 26.7%), 4 (7/30, 23.3%), and 9 (5/30, 16.7%). Interestingly some isolates collected from the same and different companies had the same PFGE type. We reported a high MDR rate in S. enterica ser. Gallinarum isolates. The present study highlights the occurrence of horizontal spread and cyclic contamination of MDR S. enterica ser. Gallinarum within the same company. Furthermore, we showed cross-contamination between different companies. The characterization of these isolates would be helpful in the development of prevention and control strategies for MDR S. enterica ser. Gallinarum infection in South Korea. [ABSTRACT FROM AUTHOR]

In this study, we investigated the characteristics of KPC-2-producing Klebsiella pneumoniae (KP-Kp) isolates from a hospital in South Korea. Among the 37 KP-Kp isolates, two main clones were identified—ST11 and ST307. ST11 isolates showed higher minimum inhibitory concentrations for carbapenems than ST307 isolates. All ST307 isolates were resistant to gentamicin and trimethoprim–sulfamethoxazole, but ST11 isolates were not. However, most tigecycline-resistant or colistin-resistant isolates belonged to ST11. The two KP-Kp clones showed different combinations of wzi and K serotypes. Plasmids from ST11 KP-Kp isolates exhibited diverse incompatibility types. Serum resistance and macrophage infection assays indicated that ST11 may be more virulent than ST307. The changes in the main clones of KP-Kp isolates over time as well as the different characteristics of these clones, including virulence, suggest the need for their continuous monitoring. [ABSTRACT FROM AUTHOR]

Hyperuricemia is a significant risk factor for cardiovascular morbidity and chronic kidney disease progression. IgA nephropathy (IgAN) is a well-known primary glomerular nephropathy. Hyperuricemia is associated with a poor prognosis in IgAN patients. We evaluated the association of hyperuricemia with the histopathological severity of IgAN in male and female patients; 658 patients diagnosed with IgAN via kidney biopsy were initially included. Baseline patient data were collected by eight university hospitals affiliated with the College of Medicine of the Catholic University of Korea. Pathological features were independently evaluated by eight expert pathologists working in the hospitals, and the consensus was reached. Of the initial 658 patients, 517 were finally included (253 males and 264 females). Hyperuricemia was defined as a serum uric acid (UA) level >7.0 mg/dL for males and >5.6 mg/dL for females; 108 (42.7%) males and 95 (35.9%) females exhibited hyperuricemia. Compared to the patients with normal UA levels, the global glomerulosclerosis, segmental sclerosis, mesangial matrix expansion (MME), endocapillary proliferation (ECP), interstitial fibrosis (IF), and tubular atrophy (TA) scores were higher in hyperuricemic males and females. In multivariable linear regression, the serum UA level correlated significantly with the MME, ECP, IF, and TA scores of female IgAN patients only. [ABSTRACT FROM AUTHOR]

We investigated fosfomycin susceptibility in Escherichia coli clinical isolates from South Korea, including community-onset, hospital-onset, and long-term care facility (LTCF)-onset isolates. The resistance mechanisms and genotypes of fosfomycin-resistant isolates were also identified. Finally, the in vitro efficacy of combinations of fosfomycin with other antibiotics were examined in susceptible or extended spectrum β-lactamase (ESBL)-producing E. coli isolates. The fosfomycin resistance rate was 6.7% and was significantly higher in LTCF-onset isolates than community-onset and hospital-onset isolates. Twenty-one sequence types (STs) were identified among 19 fosfomycin-resistant E. coli isolates, showing diverse genotypes. fosA3 was found in only two isolates, and diverse genetic variations were identified in three genes associated with fosfomycin resistance, namely, GlpT, UhpT, and MurA. Some fosfomycin-resistant E. coli isolates carried no mutations. In vitro time-kill assays showed that fosfomycin alone did not exhibit an excellent killing activity, compared with ciprofloxacin in susceptible isolates and with ertapenem in ESBL producers. However, combining fosfomycin with cefixime or piperacillin-tazobactam eradicated susceptible or ESBL-producing isolates, respectively, even with 0.5× minimum inhibitory concentrations. Overall, we found a relatively high fosfomycin resistance rate in E. coli isolates from South Korea. Based on their genotypes and resistance mechanisms, most of the fosfomycin-resistant E. coli isolates might occur independently. Antibiotic combinations with fosfomycin could be a suitable therapeutic option for infections caused by E. coli isolates. [ABSTRACT FROM AUTHOR]

Understanding the occurrence patterns of forest pests is fundamental for effective forest management from both economic and ecological perspectives. Here, we review the history of the occurrence patterns and causes of outbreaks and declines of pests in Korean pine forests over the last 50 years. During this period, the major pests of pine forests in Korea have shifted from pine caterpillar (Dendrolimus spectabilis Butler) to the pine needle gall midge (PNGM, Thecodiplosis japonensis (Uchida and Inouye)) and finally to pine wilt disease (PWD) caused by the pine wood nematode (Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle). Outbreaks of pine caterpillar, a native species in Korea, have been recorded as far back as 900 years, and it was the most relevant forest pest in Korea until the 1970s. The decline of its importance has been attributed to reforestation and higher levels of subsequent natural enemy activity. The PNGM is an invasive species, first discovered in Korea in 1929, that became widely distributed by 1992 and the major forest pest in the 1980s and 1990s. A suite of parasitic wasps attacking the PNGM contributed at least partially to the decline of PNGM densities. Following the decline of the PNGM, damage from PWD has increased since 2003. These shifts in major forest pests might be related to changes in forest composition and interactions among forest pests. Therefore, a new management strategy for controlling forest pests is required to mitigate the decline of pine forests in Korea. [ABSTRACT FROM AUTHOR]