Laboratory investigation of causes of bovine abortion and stillbirth in the Republic of Korea, 2014-2020.

Bovine abortion is a critical problem in the cattle industry. Identifying causes of abortion is key to establishing appropriate herd management and prevention strategies. We used pathology examinations, detection of etiologic agents, and serology to determine the cause of bovine abortions in Korea. We analyzed 360 abortion and stillbirth cases submitted to the Animal and Plant Quarantine Agency from December 2014 to January 2020. The putative cause of abortion was identified in 140 of 360 (38.9%) cases; 124 of the 140 (88.6%) cases were attributed to infections. The most common etiologic agents detected were bovine viral diarrhea virus (65 of 360; 18.1%), Coxiella burnetii (19 of 360; 5.3%), Leptospira spp. (13 of 360; 3.6%), Listeria monocytogenes (9 of 360; 2.5%), and Neospora caninum (8 of 360; 2.2%). Minor abortifacient pathogens included Brucella abortus (2 of 360; 0.6%), bovine alphaherpesvirus 1 (2 of 360; 0.6%), Akabane virus (2 of 360, 0.6%), and bovine ephemeral fever virus (1 of 360; 0.3%). Non-infectious conditions included congenital anomalies (7 of 360; 1.9%), goiter (7 of 360; 1.9%), and vitamin A deficiency (2 of 360; 0.6%). Our diagnostic rate in cases with placenta submitted (42 of 86; 48.8%) was significantly higher than in cases without placenta (98 of 274; 35.8%), which highlights the value of submitting placentas. Our results confirm the status of the large variety of causative agents associated with abortions in cattle in Korea.

Super-resolution techniques for biomedical applications and challenges.

Super-resolution (SR) techniques have revolutionized the field of biomedical applications by detailing the structures at resolutions beyond the limits of imaging or measuring tools. These techniques have been applied in various biomedical applications, including microscopy, magnetic resonance imaging (MRI), computed tomography (CT), X-ray, electroencephalogram (EEG), ultrasound, etc. SR methods are categorized into two main types: traditional non-learning-based methods and modern learning-based approaches. In both applications, SR methodologies have been effectively utilized on biomedical images, enhancing the visualization of complex biological structures. Additionally, these methods have been employed on biomedical data, leading to improvements in computational precision and efficiency for biomedical simulations. The use of SR techniques has resulted in more detailed and accurate analyses in diagnostics and research, essential for early disease detection and treatment planning. However, challenges such as computational demands, data interpretation complexities, and the lack of unified high-quality data persist. The article emphasizes these issues, underscoring the need for ongoing development in SR technologies to further improve biomedical research and patient care outcomes.

Novel Artificial Intelligence-Based Technology to Diagnose Asthma Using Methacholine Challenge Tests.

PURPOSE: The methacholine challenge test (MCT) has high sensitivity but relatively low specificity for asthma diagnosis. This study aimed to develop and validate machine learning (ML) models to improve the diagnostic performance of MCT for asthma. METHODS: Data from 1,501 patients with asthma symptoms who underwent MCT between 2015 and 2020 were analyzed. The patients were grouped as either the training (80%, n = 1,265) and test sets (20%, n = 236) depending on the time of referral. The conventional model (provocative concentration that causes a 20% decrease in forced expiratory volume in one second [FEV1]; PC20 ≤ 16 mg/mL) was compared with the prediction models derived from five ML methods: logistic regression, support vector machine, random forest, extreme gradient boosting, and artificial neural network. The area under the receiver operator characteristic curves (AUROC) and area under the precision-recall curves (AUPRC) of each model were compared. The prediction models were further analyzed using different input combinations of FEV1, forced vital capacity (FVC), and forced expiratory flow at 25%-75% of forced vital capacity (FEF25%-75%) values obtained during MCT. RESULTS: In total, 545 patients (36.3%) were diagnosed with asthma. The AUROC of the conventional model was 0.856 (95% confidence interval [CI], 0.852-0.861), and the AUPRC was 0.759 (95% CI, 0.751-0.766). All the five ML prediction models had higher AUROC and AUPRC values than those of the conventional model, and random forest showed both highest AUROC (0.950; 95% CI, 0.948-0.952) and AUROC (0.909; 95% CI, 0.905-0.914) when FEV1, FVC, and FEF25%-75% were included as inputs. CONCLUSIONS: Artificial intelligence-based models showed excellent performance in asthma prediction compared to using PC20 ≤ 16 mg/mL. The novel technology could be used to enhance the clinical diagnosis of asthma.

Case report: Investigation of genetic mutations in a case of schistosomus reflexus in a Holstein dairy cattle fetus in Korea.

Schistosomus reflexus (SR) is one of the most common congenital anomalies found in cases of cattle dystocia; this disorder occurs mostly in cattle. Congenital anomalies such as SR are caused by various genetic and environmental factors, but no specific cause has been elucidated for SR. This study reports a case of SR in a Holstein dairy cattle fetus with congenital anomalies in Korea. Grossly, a distinct spine curvature was observed between the thoracic and lumbar vertebrae, accompanied by a consequential malformation from the sacrum to the occipital bone. Furthermore, the thoracic and abdominal organs were exposed. In computed tomography (CT) images, mild and severe kyphoscoliosis was observed in T1~11 and L1~6, respectively. Additionally, vertebral dysplasia was observed in S1~5 and Cd 1~5. To pinpoint the causal genes and mutations, we leveraged a custom 50K Hanwoo SNP-Chip and the Online Mendelian Inheritance in Animals (OMIA) database. As a result, we identified a nonsense mutation in apoptotic protease activating factor 1 (APAF1) within HH1 that was associated with a decrease in conception rate and an increase in abortion in Holstein dairy cattle. The genotype of the SR case was A/A, and most of the 1,142 normal Holstein dairy cattle tested as a control group had the genotype G/G. In addition, the A/A genotype did not exist in the control group. Based on the pathological, genetic, and radiological findings, the congenital abnormalities observed were diagnosed as SR.

Experimental infection of post-weaned pigs with F18-encoding enterotoxigenic and enterotoxigenic/shigatoxigenic Escherichia coli strain isolated from the diarrheic feces in Korea.

Background: In the porcine industry, Escherichia coli (E. coli) infections have been causing post-weaning diarrhea (PWD) and edema disease (ED) for many years. It is classified into pathotypes and serotypes in animals according to virulence factors. Serotyping is performed for O, K, H, and F antigens, essential for discriminating pathogenicity and epidemiology. Furthermore, E. coli strains that produce F18 fimbriae are major sources of ED and PWD associated with Shiga-toxin producing E. coli (STEC) expressing F18ab and enterotoxigenic E. coli (ETEC) expressing F18ac, respectively. Aim: To investigate the pathogenicity potential and infection characteristics of experimental infection and confirm the pathological features of the Korean STEC/ETEC strains F18ab and F18ac in piglets. Methods: Three-week-old pigs were randomized into three experimental groups: infected G1 (F18ab), infected G2 (F18ac), and G3 (control). General health status was monitored daily, and pathological changes were evaluated. Results: Diarrhea occurred in all infected piglets. Pathological changes were only observed in the small intestine and regional lymph nodes. In G1, mucosal necrosis, inflammatory cell infiltration with hemorrhagic lesions, and apoptotic cell death in the tunica media of arterioles in the small intestine were observed. In contrast, the mucosa and epithelium appeared almost intact, with no abnormal vessel lesions in G2. Conclusion: Both strains, isolated from pigs in Korea, could be infected and did not spread from the alimentary tract to other organs. The pathological features were quite different among the F18 subtypes. The F18ab strain was more virulent than F18ac, and the virulence characteristics of the F18ac strain were more similar to ETEC than STEC.

Reliability and Validity of the Korean Version of the Duchenne Muscular Dystrophy Functional Ability Self-Assessment Tool.

OBJECTIVE: To systematically translate the Duchenne muscular dystrophy Functional Ability Self-Assessment Tool (DMDSAT) into Korean and verify the reliability and validity of the Korean version (K-DMDSAT). METHODS: The original DMDSAT was translated into Korean by two translators and two pediatric physiatrists. A total of 88 patients with genetically confirmed Duchenne muscular dystrophy (DMD) participated in the study. They were evaluated using the K-DMDSAT once as a self-assessment and once by an interviewer. The interviewer evaluated the K-DMDSAT again 1 week later using a test-retest approach. The intraclass correlation coefficient (ICC) was used to verify the interrater and test-retest reliabilities. Pearson correlation analysis between the K-DMDSAT and the Brooke or Vignos scales were used to assess validity. RESULTS: The total score and all domains of the K-DMDSAT showed excellent interrater and test-retest reliability, with an ICC for total scores of 0.985 and 0.987, respectively. All domains had an ICC >0.90. From the Pearson correlation analysis, the total K-DMDSAT score was significantly correlated with the Vignos and Brooke scales (r=0.918 and 0.825, respectively; p<0.001), and each domain of K-DMDSAT showed significant correlation with either the Vignos or Brooke scales. CONCLUSION: DMDSAT was systematically translated into Korean, and K-DMDSAT was verified to have excellent reliability and validity. K-DMDSAT can help clinicians easily describe and categorize various functional aspects of patients with DMD through the entire disease progression.

Development and evaluation of an online mental health program for traumatized female college students: A randomized controlled trial.

This study developed and evaluated an online mental health program for female college students who experienced trauma, based on Roy's Adaptation Model. A randomized controlled trial was adopted. Participants completed a survey on trauma and post-traumatic stress symptoms. Data from experimental and control groups (n = 16) were collected over two months. The program reduced post-traumatic stress and depression symptoms and improved functional health and adjustment. This effect was sustained in experimental group participants for one month post-program. The findings revealed the effectiveness of Internet mental healthcare for female students and the crucial role nurses play in it.

Case study: Pathological and phylogenetic analysis of coccidiosis in two goats with heavy infection of unrecorded Eimeria sp.

Two 3-month-old goats (Capra aegagrus hircus and C. hircus coreanae) died after ataxia. In both goats, white nodules 3 mm in diameter were scattered from the duodenum to the ileum and well-raised white nodules 2-3 mm-diameter in the mucosa of the small intestine. Histopathologically, numerous mucosal polyps with coccidial oocysts were observed in the small intestine and several schizonts, macrogametocytes, microgametocytes, and macrogametes were observed in mucosal polyps in the jejunum. Based on fecal flotation tests, the oocysts morphologically resembled those of Eimeria christenseni and E. sundarbanensis; however, their sizes were different. The 18S rRNA gene and COI were phylogenetically analyzed for the molecular identification and characterization of Eimeria sp. Based on 18S rRNA gene similarity, the isolates formed an independent cluster within the related goat Eimeria clade, and the closest species were E. christenseni C2_42, E. hirci C2_99, and E. arloingi C2_119. Furthermore, these were also distinguished from other related goat Eimeria spp. in the phylogenetic tree based on the COI gene. Considering all histopathological, morphological, and phylogenetic analyses, the current study was diagnosed as fatal coccidiosis due to heavy infection with an unrecorded Eimeria species. Thus, we report in this study with caution regarding coccidiosis caused by an unrecorded Eimeria.

Epidemiological investigation of equine hindlimb ataxia with Setaria digitata in South Korea.

BACKGROUND: Since 2013, the number of requests for diagnosis for horses based on neurological symptoms has increased rapidly in South Korea. The affected horses have commonly exhibited symptoms of acute seasonal hindlimb ataxia. A previous study from 2015-2016 identified Setaria digitata as the causative agent. OBJECTIVES: This study is an epidemiological investigation to find out risk factors related to the rapid increase in hindlimb ataxia of horses due to aberrant parasites in South Korea. METHODS: An epidemiological investigation was conducted on 155 cohabiting horses in 41 horse ranches where the disease occurred. The surrounding environment was investigated at the disease-causing horse ranches (n = 41) and 20, randomly selected, non-infected ranches. RESULTS: Hindlimb ataxia was confirmed in nine cohabiting horses; this was presumed to be caused by ectopic parasitism. Environments that mosquitoes inhabit, such as paddy fields within 2 km and less than 0.5 km from a river, had the greatest association with disease occurrence. CONCLUSIONS: Most horse ranches in South Korea are situated in favorable environments for mosquitoes. Moreover, the number of mosquitoes in the country has increased since 2013 due to climate change. Additional research is required; however, these data show that it is necessary to establish guidelines for the use of anthelmintic agents based on local factors in South Korea and disinfection of the environment to prevent disease outbreaks.

Stabilization and Tracking of a Quadrotor Using Modified Sigmoid Sliding Mode Control.

A modified sigmoid sliding mode control (MS-SMC) approach is proposed for stabilizing and tracking a quadrotor system with a nonlinear sliding surface, where the dynamics model is underactuated, highly coupled, and nonlinear. The constructed nonlinear sliding surface is based on the traditional sliding mode surface with a modified sigmoid function, allowing the initial value to quickly reach equilibrium. A new type of nonlinear SMC is applied for performance improvement of the quadrotor using the proposed modified sigmoid sliding surface. To control the quadrotor effectively, a double-loop control method is used to design the control rate, in which the position subsystem is the outer loop, and the attitude subsystem is the inner loop.With the Lyapunov function, the stability of the overall closed-loop system is ensured by stabilizing each subsystem step by step. Moreover, from a practical point of view, the system performance under the model uncertainties and external disturbances are also considered. The simulation results show that the proposed MS-SMC performs better than the conventional sliding mode control (CSMC) and the back-stepping sliding mode control (BS-SMC) in terms of stabilization and tracking against external disturbances.

Imbalanced Seismic Event Discrimination Using Supervised Machine Learning.

The discrimination between earthquakes and artificial explosions is a significant issue in seismic analysis to efficiently prevent and respond to seismic events. However, the discrimination of seismic events is challenging due to the low incidence rate. Moreover, the similarity between earthquakes and artificial explosions with a local magnitude derives a nonlinear data distribution. To improve the discrimination accuracy, this paper proposes machine-learning-based seismic discrimination methods-support vector machine, naive Bayes, and logistic regression. Furthermore, to overcome the nonlinear separation problem, the kernel functions and regularized logistic regression are applied to design seismic classifiers. To efficiently design the classifier, P- and S-wave amplitude ratios on the time domain and spectral ratios on the frequency domain, which is converted by fast Fourier transform and short-time Fourier transform are selected as feature vectors. Furthermore, an adaptive synthetic sampling algorithm is adopted to enhance the classifier performance against the seismic data imbalance issue caused by the non-equivalent number of occurrences. The comparisons among classifiers are evaluated by the binary classification performance analysis methods.

Bacterial Profiles of Brain in Downer Cattle with Unknown Etiology.

Downer cow can be caused by muscular paralysis, neurological damage, metabolic disorder, and/or the complication of microbial infection. However, downer cow with unknown etiology is issued because of the non-detection of its bacterial etiological agent. In this study, differences in the bacterial community in brain tissues between downer cattle with unknown etiology and healthy slaughtered cattle are investigated. Bacterial diversity and representative genera between downer and normal cattle were significantly different (p < 0.05). There are significant differences in representative genera of downer and normal cattle, especially the significance, fold change, and area under the receiver operating characteristic curve score (p < 0.05). Furthermore, the prediction of functional genes in brain microbiota between the downer and normal cattle revealed differences in the cluster of orthologous gene categories, such as lipid transport and metabolism, secondary metabolite biosynthesis, and signal transduction (p < 0.05). This study revealed a significant difference in microbiota between the downer and normal cattle. Thus, we demonstrate that representative genera from downer cattle through 16S rRNA gene amplicon sequencing and microbiota analysis have the potential as candidates for bacterial etiological agents for downer cow.

Astrovirus Infection in Cattle with Nonsuppurative Meningoencephalitis in South Korea.

Neurological diseases in cattle can be caused by several infectious agents. Astroviruses are increasingly recognized as the causative agent of encephalitis in various animals, including humans. In this study, a neuroinvasive astrovirus (BoAstV 20B05) was discovered in the brain tissues of an 81-month-old Korean native cattle with neurological symptoms. Lymphocyte infiltration and multifocal perivascular cuffing were observed in the cerebrum and brain stem, and viral antigens were also detected in the meninges. In particular, the concentration of the astroviral genome was high in the brain tissues. Korean BoAstV 20B05 was classified into the CH13/NeuroS1 clade and was closely related to the Neuro-Uy and KagoshimaSR28-462 strains. Our evolutionary analysis showed that Korean BoAstV 20B05 belongs to the sub-lineage NeuroS1 and evolved independently of BoAstV KagoshimaSR28-462. These results suggest that neuroinvasive astroviruses were first introduced in Korea. However, analysis is limited by the lack of reference astrovirus sequences reported in various countries within Asia, and further analysis should be performed using more strains. In this study, we identified a neuroinvasive astrovirus infection with neurological symptoms for the first time in South Korea and confirmed that BoAstV 20B05 may have been introduced in South Korea a long time ago.

The Relationship Between Breast Density Change During Menopause and the Risk of Breast Cancer in Korean Women.

BACKGROUND: The aim of this study was to investigate the relationship between changes in breast density during menopause and breast cancer risk. METHODS: This study was a retrospective, longitudinal cohort study for women over 30 years of age who had undergone breast mammography serially at baseline and postmenopause during regular health checkups at Samsung Medical Center. None of the participants had been diagnosed with breast cancer at baseline. Mammographic breast density was measured using the American College of Radiology Breast Imaging Reporting and Data System. RESULTS: During 18,615 person-years of follow-up (median follow-up 4.8 years; interquartile range 2.8-7.5 years), 45 participants were diagnosed with breast cancer. The prevalence of dense breasts was higher in those who were younger, underweight, had low parity or using contraceptives. The cumulative incidence of breast cancer increased 4 years after menopause in participants, and the consistently extremely dense group had a significantly higher cumulative incidence (CI) of breast cancer compared with other groups [CI of extremely dense vs. others (incidence rate per 100,000 person-years): 375 vs. 203, P < 0.01]. CONCLUSION: Korean women whose breast density was extremely dense before menopause and who maintained this density after menopause were at two-fold greater risk of breast cancer. PREVENTION RELEVANCE: Extremely dense breast density that is maintained persistently from premenopause to postmenopause increases risk of breast cancer two fold in Korean women. Therefore, women having risk factors should receive mammography frequently and if persistently extremely dense breast had been detected, additional modalities of BC screening could be considered.

Evaluation of the Variability of the ORF34, ORF68, and MLST Genes in EHV-1 from South Korea.

Equine herpesvirus-1 (EHV-1) is an important pathogen in horses. It affects horses worldwide and causes substantial economic losses. In this study, for the first time, we characterized EHV-1 isolates from South Korea at the molecular level. We then aimed to determine the genetic divergences of these isolates by comparing them to sequences in databases. In total, 338 horse samples were collected, and 12 EHV-1 were isolated. We performed ORF30, ORF33, ORF68, and ORF34 genetic analysis and carried out multi-locus sequence typing (MLST) of 12 isolated EHV-1. All isolated viruses were confirmed as non-neuropathogenic type, showing N752 of ORF30 and highly conserved ORF33 (99.7-100%). Isolates were unclassified using ORF68 analysis because of a 118 bp deletion in nucleotide sequence 701-818. Seven EHV-1 isolates (16Q4, 19R166-1, 19R166-6, 19/10/15-2, 19/10/15-4, 19/10/18-2, 19/10/22-1) belonged to group 1, clade 10, based on ORF34 and MLST analysis. The remaining 5 EHV-1 isolates (15Q25-1, 15D59, 16Q5, 16Q40, 18D99) belonged to group 7, clade 6, based on ORF34 and MLST analysis.

Setaria digitata was the main cause of equine neurological ataxia in Korea: 50 cases (2015-2016).

This study was performed to examine and clarify the cause of hindlimb ataxia and neuropathy seen in the South Korean horse population. Fifty horses diagnosed with hindlimb ataxia and neuropathy were referred for this study. Neurological examination was performed on 47 horses while necropsy was performed in all 50 animals. The occurrence of neurological diseases increased rapidly in the summer and 47 out of 50 horses were referred after the end of July. The incidence of neurological diseases started from the southern part of Korea in July and proceeded northward in August and September. Although there was no correlation with age, Thoroughbred and Warmblood horses showed a higher incidence rate than Halla and Jeju horses. The incidence rate was 5 times higher in geldings than in mares and stallions. Of the 20 cases, 16 were diagnosed with eosinophilic meningoencephalomyelitis in 2015. The most common lesions observed in 2016 were parasitic meningoencephalomyelitis (10 cases, 33%) and eosinophilic meningomyelitis (7 cases, 23%). Histopathological analysis of the brain and spinal cord revealed nematodes of approximately 100-200 µm in diameter, microcavitation and infiltrates of eosinophils, and brown pigmented macrophage infiltrates. The nematodes were identified as Setaria digitata via DNA sequencing, performed subsequent to polymerase chain reaction using DNA isolated from formalin-fixed paraffin-embedded tissue sections of the spinal cord. These results show that aberrant migration of Setaria digitata larva in the brain and spinal cord was a major cause for neurological signs in horses.

Iterative Regression Based Hybrid Localization for Wireless Sensor Networks.

Among various localization methods, a localization method that uses a radio frequency signal-based wireless sensor network has been widely applied due to its robustness against noise factors and few limits on installation location. In this paper, we focus on an iterative localization scheme for a mobile with a limited number of time difference of arrival (TDOA) and angle of arrival (AOA) data measured from base stations. To acquire the optimal location of a mobile, we propose a recursive solution for localization using an iteratively reweighted-recursive least squares (IR-RLS) algorithm. The proposed IR-RLS scheme can obtain the optimal solution with a fast computational speed when additional TDOA and/or AOA data is measured from base stations. Moreover, while the number of measured TDOA/AOA data was limited, the proposed IR-RLS scheme could obtain the precise location of a mobile. The performance of the proposed IR-RLS method is confirmed through some simulation results.

Seismic Discrimination between Earthquakes and Explosions Using Support Vector Machine.

The discrimination between earthquakes and explosions is a serious issue in seismic signal analysis. This paper proposes a seismic discrimination method using support vector machine (SVM), wherein the amplitudes of the P-wave and the S-wave of the seismic signals are selected as feature vectors. Furthermore, to improve the seismic discrimination performance using a heterodyne laser interferometer for seismic wave detection, the Hough transform is applied as a compensation method for the periodic nonlinearity error caused by the frequency-mixing in the laser interferometric seismometer. In the testing procedure, different kernel functions of SVM are used to discriminate between earthquakes and explosions. The outstanding performance of a laser interferometer and Hough transform method for precision seismic measurement and nonlinearity error compensation is confirmed through some experiments using a linear vibration stage. In addition, the effectiveness of the proposed discrimination method using a heterodyne laser interferometer is verified through a receiver operating characteristic curve and other performance indices obtained from practical experiments.

Co-infection of Dirofilaria immitis and Japanese encephalitis virus in a spotted seal (Phoca largha) in the Republic of Korea.

A 10-year-old male spotted seal presented with loss of appetite and decreased activity. Grossly, the internal organs revealed several filarial nematodes in the right ventricle of the heart and the pulmonary vessels. Histopathological examination of the brain revealed moderate nonsuppurative meningoencephalitis with glial nodules and neuronophagia. Japanese encephalitis virus (JEV) of genotype I was isolated from the brain. All nematodes were identified as Dirofilaria immitis. This is the first clinical case of co-infection with D. immitis and JEV in a seal, suggesting that the seal, may be a dead-end host, like the human and horse, for JEV.