• Safety and Health at Work
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• v.13 no.3
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• pp.263-268
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• 2022

Health care workers (HCWs) are more than ten times more likely to be infected with coronavirus infectious disease 2019 (COVID-19) than the general population, thus demonstrating the burden of COVID-19 among HCWs. Factors that expose HCWs to a differentially high-risk of COVID-19 acquisition are important to elucidate, enable appropriate public health interventions to mitigate against high risk and reduce adverse outcomes from the infection. We conducted a systematic review and meta-analysis to summarize and critically analyze the existing evidence on SARS-CoV-2 risk factors among HCWs. With no geographical limitation, we included studies, in any country, that reported (i) the PCR laboratory diagnosis of COVID-19 as an independent variable (ii) one or more COVID-19 risk factors among HCWs with risk estimates (relative risk, odds ratio, or hazard ratio) (iii) original, quantitative study design, and published in English or Mandarian. Our initial search resulted in 470 articles overall, however, only 10 studies met the inclusion criteria for this review. Out of the 10 studies included in the review, inadequate/lack of protective personal equipment, performing tracheal intubation, and gender were the most common risk factors of COVID-19. Based on the random effects adjusted pooled relative risk, HCWs who reported the use of protective personal equipment were 29% (95% CI: 16% to 41%) less likely to test positive for COVID-19. The study also revealed that HCWs who performed tracheal intubations were 34% (95% CI: 14% to 57%) more likely to test positive for COVID-19. Interestingly, this study showed that female HCWs are at 11% higher risk (RR 1.11 95% CI 1.01-1.21) of COVID-19 than their male counterparts. This article presents initial findings from a living systematic review and meta-analysis, therefore, did not yield many studies; however, it revealed a significant insight into better understanding COVID-19 risk factors among HCWs; insights important for devising preventive strategies that protect them from this infection.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.44-51
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• 1995

This investigation was conducted to determine the effect of the optimum planting date and place for good seed production on growth variation, grain yields, different of variety, infection of seed by fungi, and seed germination and vigor after room storage. Early maturity Korean soybean variety, Keunolkong, and introduced vegetable soybean variety, Fukura-edamame, were planted at field of YAES. and high cool land of Sajapyong in Milyang（altitude, 850m） on May 15 （early）, June 15 （mid.）, and July 15 （late） in 1991. The emergence and vegetative period gradually increased in the early planting date. The grain yield, seed weight, pod number, healthy grain yield also increased when Keunolkong was planted on early date. The healthy seed rate, Keunolkong increased in the early planting date, whereas that of Fukura also increased in the late planting date. Infection ratio of grain to phomopsis seed decay （Phomopsis spp. ' Diaporthe phaseolorum） in Fukura steadily increased in the early planting date. Infection ratio of grain to purple seed stain （Cercospora kikuchii） generally increased in the mid and late planting date. The seed germination and seedling vigor after room storage from five to six months gradually increased in the late planting date. And seed germination of Fukura rapidly decreased in the early planting date. Therefore, the optimum planting date for good seed production in early maturity vegetable soybean was June 15 in terms of harvesting time avoid a high temprature and humidity.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.599-607
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• 2016

The first patient of Middle East respiratory syndrome caused by a novel coronavirus infection in Korea was confirmed on May 20, 2015. After that, MERS spread over the country. In recent years, patients of MERS have been found around the Arabian Peninsula and the case fatality ratio of MERS in those area was been reported to range from 30 to 40%. In this paper, we estimate the case fatality ratio of MERS of Korea using data of 186 infections until December 1, 2015. In this study we propose a novel estimator of the case fatality ratio using information of the patients severity condition as well as records on the days of confirmation and death or recovery of the patient. By using publicly available data of the Department of Health and Human Services Centers for Disease Control, we evaluate a performance of the estimator and demonstrate a stability of the estimator from the early stage of the epidemic.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.303-309
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• 1999

Mass mortality of the Manila clam, Ruditapes philippinarum has been reported all along the west and south coast of Korea for the past several years. As a pathogenic agent, Perkinsus sp., an endoparasitic protozoan has been identified in this study and believed to be responsible for the mass mortalities. Prevalence and infection intensity of Perkinsus sp. was investigated from a Manila clam population inhabiting at Komsoe Bay in the west coast where mass mortality of the clam has been reported. A total of 142 Manila clam, 50 oyster, Crassostrea gigas, 10 ark shell, Scapharca broughtonii, and 5 predatory gastropada, Rapana venosa were examined for the presence and the quantity of Perkinsus sp. Ray's fluid thioglycollate medium method (FTM method) with modified Mackin's infection intensity scale and Choi's quantitative method were used in detecting and quantifying the parasite. All individuals of R. philippinarum examined in this study were infected with Perkinsus sp., indicating $100\%$ prevalence while none of the oysters and the gastropods exhibited the parasite. Six to ten individual hypnospores of Perkinsus sp. were counted from the ark shells. The number of hypnospores in the clam tissues varied from 16,667 to 4,091,667, with a mean number of 1,077,628. Average infection intensity according to Mackin's was 2.87, indicating a moderate infection. A negative correlation was observed between the number of Perkinsus sp. in the tissue and the condition index, a ratio tissue wet weight to shell cavity volume. The clam size and the infection intensity in terms of total number of parasites were positively correlated; the bigger clam, the heavier infection. Such high number of Perkinsus sp. counted in the clams could be enough to cause physiological disturbance of clams, such as retarded growth and reproduction. It is also believed that such a high infection leads mortality of the clam via continuous draining of the energy by metabolic activities and reproduction of the parasites. Correlation between the condition index and the infection intensity observed in this study supports this hypothesis.

• Pediatric Infection and Vaccine
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• v.17 no.2
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• pp.122-129
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• 2010

Purpose : Enteroviral infection is a common viral illness in children. We undertook this study in attempt to comprehend the epidemiologic and clinical features of enteroviral infections, particularly EV71 in children. Methods : We enrolled 63 children with enteroviral infection at Severance Children's Hospital in Seoul between May and August 2009. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed from stool or cerebrospinal fluid samples, which were then tested for enteroviral infection. Viral isolation and serotype identification also were performed by RT-PCR. Results : A total of 63 patients with clinical diagnosis of enteroviral infections were enrolled; of those, 38 (60%) were positive for enterovirus. The mean age of the patients was 2 years and 7 months and the sex ratio of male to female was 0.9 :1. Their clincal manifestations included aseptic meningitis (21 cases, 55%), HFMD (16 cases, 42%), herpangina (5 cases, 13%), neonatal fever (2 cases, 5%), encephalitis (1 case, 3%), and myocarditis (1 case, 3%). Serotypes of isolated enteroviruses were EV71 (8 cases, 21%), coxsackievirus B1 (8 cases, 21%), coxsackievirus A16 (2 cases, 6%), coxsakievirus A2 (1 case, 3%), coxsakievirus A5 (1 case, 3%), and echovirus 9 (1 case, 3%). Clinical symptoms of EV71 infection included HFMD (5 cases, 63%), aseptic meningitis (3 cases, 38%), encephalitis (1 case, 13%), and myocarditis (1 case, 13%). A positive rate of C-reactive protein in EV71 was higher than those in other enterviral infections. However, there was no statistically significant difference in other laboratory findings. Conclusion : We reported on identified enteroviruses, including EV71, during a period of 3 months in the summer of 2009. In this study, EV71 infection frequently occurred in male and clinical manifestation caused by EV71 was a more severe disease than that due to other enterviral infections. There is a need for continuous surveillance of enteroviral infection and its clinical manifestations for diagnosis and treatment of enteroviral infection.

• Childhood Kidney Diseases
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• v.3 no.1
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• pp.72-79
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• 1999

Renal scarring associated with vesico-ureteral reflux(VUR) is one of the major causes of end stage renal failure and renal hypertension in children. Urinary ${\beta}_2$-microglobulin(MG) has been suggested as a potential marker for presence of renal tubular damage. This study was designed to evaluate the significance of random urine ${\beta}_2$-MG as a predictor of presence of vesico-ureteral reflux in children with urinary tract infection(UTI). 57 children with urinary tract infection were studied. Patients were devided into two groups; 35($78.9\%$) children have UTI without VUR and 12($21.1\%$) children have UTI and VUR. Beta2-MG and creatinine in random urine sample was measured to decide the excretion ratio(${\beta}_2$-MG/creatinine). Among the 57 children with UTI, 44 children were confirmed by urine culture study and 13 children suspected by compatible clinical feature. Random urine ${\beta}_2$-MG of VUR group ($2.2{\pm}5.91$ mg/L) were significantly higher than that of simple UTI group($0.19{\pm}0.16mg/L$)(P=0.03). The ${\beta}_2$-MG/creatinine ratio of VUR group($32.41{\pm}25.7$) were significantly higher than that of simple UTI group($3.93{\pm}3.44$)(P=0.007). In conclusion, random urine ${\beta}_2$-MG and excretion ratio deserved early predictor of presence of VUR in children with UTI. And this method was more simple and inexpensive than the method of measuring ${\beta}_2$-MG with 24 hour urine collection, so might be a useful screening test for VUR in children with UTI.

• Clinical and Experimental Pediatrics
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• v.51 no.8
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• pp.827-833
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• 2008

Purpose : Early identification of iron deficiency in young children is essential to prevent damaging long-term consequences. It is often difficult for the pediatrician to know which indices should be used when diagnosing these conditions especially in hospitalized young children. This study investigated the clinical significances of reticulocyte hemoglobin content in young children with acute infection. Methods : We studied 69 young children aged from 6 to 24 months admitted with acute infection in a single center. Venous blood was drawn to determine hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), hemoglobin content (CH), reticulocyte hemoglobin content (CHr), and red blood cell distribution width (RDW) using ADVIA 120 (Bayer Diagnostics, NY, USA). For evaluating iron status, iron, total iron binding capacity, ferritin and transferrin saturation (Tfsat) were determined. Iron deficiency was defined as Tfsat less than 20%, and iron deficiency anemia as Tfsat less than 20% and Hb level less than 11 g/dL. Results : In all, 47 were iron deficient; 17 of these had iron deficiency anemia. CHr was the only significant predictor of iron deficiency (likelihood ratio test=71.25; odds ratio=0.67; P<0.05). Plasma ferritin level had no predictive value (P=0.519). Subjects with CHr less than 27.4 pg had lower Hb level, MCH, CH, Tfsat, and iron levels than those with CHr 27.4 pg or more (P<0.05 for all). Conclusion : CHr level was a sensitive screening tool and the strongest predictor of iron deficiency in hospitalized infants with acute infection; it was cost saving and avoiding additional sampling. However its reference range should be established.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.1
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• pp.42-47
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• 1990

Silage productivity of 7 corn and 3 sorghum hybrids was determined at two planting dates differing in rice black-streaked dwarf virus (RBSDV) infection rates in the southern part of Korea where RBSDV is prevalent. 1. Percent stand was similar between two planting dates, but that of corn hybrids (85.0-99.5 %) was higher compared with sorghum (59.8-82.3 %). Culm length of corn hybrids at April 23 planting was longer compared with May 20 planting, but that of sorghum hybrids was similar between two planting dates. 2. RBSDV infection rate of corn hybrids at April 23 planting was lower compared with May 20 planting, but sorghum was not infected at both planting dates. Among corn hybrids Suweon 19 was most severely infected, but Suweon 99 was least infected at both planting dates. 3. Percent ear bearing plants and earltotal dry matter (TDM) ratio of corn hybrids at April 23 planting was higher than those of May 20 planting. Among the corn hygrids percent ear beraring plants, ear/TDM ratio of Suweon 19 was lowest at both planting dates due to severe RBSDV infection. Ear/TDM ratio of sorghum hybrids was below 17.8 % due to sterility and partially bud damages. 4. Silage yield at April 23 planting was higher than that at May 20 planting and sorghum hybrids outyielded corn hybrids. Silage yield of Suweon 19 and Jinjuok was lowest due to severe RBSDV infection. 5. Crude protein was similar regardless planting dates, species, and varieties except the lowest P 931. Ether extract at April 23 planting was lower then that at May 20 and corn was lower compared with sorghum hybrids. Crude fiber and nitrogen free extracts(NFE) was similar between planting dates. Crude fiber of corn was lower, but NEF was higher compared with sorghum, but similar among hybrids in a species. 6. In vitro dry matter digestibility (IVDMD) at May 20 planting was higher than that of April 23 planting and corn was higher than sorghum hybrids. Digestible dry matter (DDM) of both corn and sorghum at April 23 planting was higher than that of May 20 planting. At April 23 planting DDM of all corn and sorghum hybrids was similar, but DDM of Suweon 19 and Jinjuok was lower than other corn and sorghum hybrids.

• Tuberculosis and Respiratory Diseases
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• v.59 no.4
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• pp.389-396
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• 2005

Background : Central venous catheters(CVCs) area major source of nosocomial infection. Chlorhexidine-silver sulfadiazine coated catheters (CHSS) were developed to reduce the rate of CVC infection. However, the clinical effectiveness of CHSS in comparison wth non-coated catheter (NCC) remains to be evaluated. Methods : From January 2004 to December 2004 in medical intensive care unit (ICU) of Asan Medical Center, CVCs were inserted in 446 cases. We retrospectively analyzed characteristics of patients and catheterization,the catheter-related infection rate and colonization, microbiologic findings, and insertion sites (subclavian, jugular, femoral) according to the type of inserted CVCs (NCC: 187 cases, CHSS: 259 cases). Catheter related infection is defined as catheter related bacteremia and catheter related non-bacteremic sepsis. Results : 1) The mean age of the patients in each group was $62{\pm}16$ years, $63{\pm}15$ years (p=0.42), and sex ratio 94:50, 141:69 (p=0.9) in NCC and CHSS. Duration of ICU admission ($29{\pm}37$, $26{\pm}44$ p=0.42), duration of mechanical ventilation ($17{\pm}22$, $15{\pm}19$ p=0.17), and APACHE III score at the time of CVC insertion ($81{\pm}34$, $82{\pm}37$ p=0.61) were not different between both groups. 2) Mean duration of catheterization was 118 in NCC and 119 in CHSS (p=0.98). Number of catheter-days was 2176 days in NCC and 3035 days in CHSS. Catheter-related infection occurred in 9 (4.8%) cases receiving NCC and 4 cases (1.5%) receiving CHSS. Catheterrelated infection incidence per 1000 catheter-days was 4.1 and 1.3, respectively (p=0.04). CHSS was associated with a significant reduction of infection in jugular catheters regarding to insertion sites (p=0.01). 3) Microorganisms causing infection were Staphylococcus aureus (n=3), Candida (n=3), coagulase-negative Staphylococci (n=2), and Klebsiella (n=1) in NCC, and Candida species (n=2), coagulase-negative Staphylococci (n=2), Proteus (n=1) in CHSS. Conclusion : CHSS has significantly reduced the episodes of infection compared to NCC in jugular catheterization in medical ICU.

• Pediatric Infection and Vaccine
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• v.24 no.3
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• pp.168-177
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• 2017

Purpose: The purpose of this study was to analyze the clinical features and risk factors of invasive infections caused by Lactobacillus spp. and Saccharomyces spp., components of commercially available probiotics. Methods: We analyzed demographic and clinical data from children ${\leq}18$ years of age with an invasive infection caused by Lactobacillus spp. or Saccharomyces spp. at the Asan Medical Center Children's Hospital from January 1998 to June 2016. Probiotic consumption data were also analyzed. Results: During the study period, a total of 24 episodes of invasive infections were caused by Lactobacillus spp. (n=16) and Saccharomyces cerevisiae (n=8). Along with the increase of probiotic use (755,594 [days/1,000 patient-admission days] in 2001 to 2005, 1,444,066 in 2006 to 2010, and 6,904,736 in 2011 to 2016), the incidence of probiotic-associated invasive infection increased ($R^2=0.70$). The median age of the patients was 1.8 years (range, 2 months to 17 years), and most of them had underlying medical conditions. The 30-day mortality rate was 20.8% (5/24), and 11 (45.8%) of these patients resulted from a severe invasive infection. We determined the risk factors for invasive infection to be: previous intensive care unit stay (odds ratio [OR], 3.0; 95% confidence interval [CI], 1.5 to 6.1] and the presence of a central venous catheter (OR, 2.2; 95% CI, 1.2 to 4.3). Conclusions: Although the probiotic-associated invasive infections rarely occurred in children, the incidence has increased along with probiotic pressure. Judicious use of probiotics is mandatory, especially in young children with underlying medical conditions and continuous surveillance will be needed to minimize the safety concerns.