Seroprevalence and Risk Factors for Severe Fever with Thrombocytopenia Syndrome among the Korea National Park Service Workers / 農村醫學 地域保健

Objectives@#This study was carried out to understand the seroprevalence and risk factors for severe fever with thrombocytopenia syndrome (SFTS) among the Korea National Park Service (KNPS) workers. @*Methods@#We used the stored serum samples (763) and survey results collected from the previous investigation on scrub typhus and Lyme disease among the KNPS workers during 2016-2017. The serum samples were analyzed by double-antigen sandwich enzyme-linked immunosorbent assay, which was used to test the total antibody including IgG and IgM. @*Results@#The SFTS seroprevalence among the KNPS worrkers was 1.4%. In multivariate logistic analysis, the national park exploration programs (odds ratio, 3.48; 95% confidence interval, 1.01-12.01) was significantly associated with the seroprevalence of SFTS. @*Conclusion@#This study was the first serological study of SFTS among forestry workers in South Korea. Although the KNPS workers are at a high-risk group of SFTS, the prevention activities related to the working environment and habit was insufficient. Thus, systematic prevention education and training for the KNPS workers need to be strengthened.

COVID-19 Outbreak and Presymptomatic Transmission in Pilgrim Travelers Who Returned to Korea from Israel

Background@#On February 21, 2020, 2 coronavirus disease 2019 (COVID-19) cases in pilgrim travelers from Korea to Israel were identified. We investigated the source of infection, clinical features of COVID-19, and transmission potential of presymptomatic and asymptomatic cases. @*Methods@#All 39 pilgrim travelers were aggressively tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Their clinical features and possible source of infection were investigated by interview and review of their medical records. Ten confirmed cases without symptoms at the first sampling dates were selected for follow-up reverse transcription polymerase chain reaction tests. @*Results@#Of the 39 pilgrim travelers, 30 (77%) were positive for SARS-CoV-2. Among the 30 positive COVID-19 cases, 4 (13%) were asymptomatic. Available follow-up cycle threshold values from 10 cases gradually increased over time and were lower during the presymptomatic period than during the postsymptomatic period. Out of 328 contacts related to the COVID-19 cases in the pilgrim travelers, 22 additional cases (7%) were confirmed with SARS-CoV-2 infections. Three tertiary cases were identified to be transmitted by presymptomatic secondary cases. @*Conclusion@#To prevent transmission of COVID-19, we need to focus on presymptomatic and asymptomatic cases, and massive testing for SARS-CoV-2 is required. More research about the possibility of presymptomatic transmission over 2 days before symptom onset is required.

COVID-19 in Nursing Facilities: Experience in Republic of Korea

ObjectivesCoronavirus disease 2019 (COVID-19) outbreaks in nursing facilities can easily lead to a high rate of infection and fatality. A surge in newly infected cases in the first quarter of 2020 in Gyeongsan-si, in the Republic of Korea, was followed by several outbreaks in nursing facilities in the same area. The aim of this study is to report on the epidemiological investigation and the management to reduce the infection rate in nursing facilities for older adults.MethodsThe municipal government and the Korea Centers for Disease Control and Prevention performed an epidemiological investigation into 5 nursing facilities that reported a high number of COVID-19 infection cases from February to May 2020. COVID-19 infected cases in the facilities were investigated to identify the infection routes, and the fatality rate of the 5 facilities.ResultsThe 5 facilities had a combined fatality rate of 12.2% (9 deceased among the 74 infected cases). The median age of the deceased was 87 years old (range: 82–91). The infection was first identified on February 27th, 2020, peaked on March 6th, and was last detected on March 24th, 2020.ConclusionDifficulties specific to such facilities included the delay in the recognition of symptoms and limitation in distancing. Tailored strategies such as daily monitoring of symptoms and proactive COVID-19 screening of quarantined residents, contributed to a decline in the infections in the facilities.

COVID-19 Outbreak and Presymptomatic Transmission in Pilgrim Travelers Who Returned to Korea from Israel

Background@#On February 21, 2020, 2 coronavirus disease 2019 (COVID-19) cases in pilgrim travelers from Korea to Israel were identified. We investigated the source of infection, clinical features of COVID-19, and transmission potential of presymptomatic and asymptomatic cases. @*Methods@#All 39 pilgrim travelers were aggressively tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Their clinical features and possible source of infection were investigated by interview and review of their medical records. Ten confirmed cases without symptoms at the first sampling dates were selected for follow-up reverse transcription polymerase chain reaction tests. @*Results@#Of the 39 pilgrim travelers, 30 (77%) were positive for SARS-CoV-2. Among the 30 positive COVID-19 cases, 4 (13%) were asymptomatic. Available follow-up cycle threshold values from 10 cases gradually increased over time and were lower during the presymptomatic period than during the postsymptomatic period. Out of 328 contacts related to the COVID-19 cases in the pilgrim travelers, 22 additional cases (7%) were confirmed with SARS-CoV-2 infections. Three tertiary cases were identified to be transmitted by presymptomatic secondary cases. @*Conclusion@#To prevent transmission of COVID-19, we need to focus on presymptomatic and asymptomatic cases, and massive testing for SARS-CoV-2 is required. More research about the possibility of presymptomatic transmission over 2 days before symptom onset is required.

Seroprevalence and risk factors of Lyme disease among Korean deer farmers / 農村醫學 地域保健

No abstract available.

A Study on the Febrile Illness in Autumn among Farmers in Gyeongju-si: Scrub typhus, Leptospirosis, HFRS / 農村醫學 地域保健

OBJECTIVES: This study aimed to assess the status of Scrub typhus, Leptospirosis and HFRS(hemorrhagic fever with renal syndrome) among farmers with febrile illness. METHODS: We involved a total of 841 farmers who had febrile illness(508 and 333 village residents were, respectively, three and four district of Gyeongju city) selected during autumn of 2014 and 2015. Data were collected by survey questionnaires and blood sample examination. RESULTS: Serum response rate for Scrub typhus and Leptospirosis was 1.5% each and 1.9% for HFRS. Serum response rate for Scrub typhus was significantly higher for tick-bite cases(38.5%), while Leptospirosis was significantly higher for those who were in fruit–planting work(23.1%). Similarly, serum response rate was significantly higher for HFRS who were working in venyl green house work(25.0%). CONCLUSIONS: Government authority should develop effective and efficient preventive strategies to create awareness of infectious diseases among farmers. Extending information, education and communication be reached to farmers that could change their perception and help early diagnosis and treatment and reduce the disease burden and its complication.

Serologic Survey and Risk Factors for Coxiella burnetii Infection among Dairy Cattle Farmers in Korea

BACKGROUND: The zoonotic disease Q fever is caused by Coxiella burnetii and usually affects high-risk human populations. We conducted a serological survey of dairy cattle farmers in Korea to determine seroreactivity and identify risk factors for C. burnetii infection. METHODS: This cross-sectional study included 1,824 of 7,219 dairy cattle farms (25.3%) in the study region. The selected dairy cattle farmers visited the nearest public health centers or branches with completed questionnaires. Serum samples from the farmers were tested using an indirect immunofluorescence assay to detect phase II C. burnetii immunoglobulin (Ig) G or M antibodies. RESULTS: A total of 1,222 dairy cattle farmers from 784 dairy cattle farms (43.0%) participated in this study, and 11.0% (134/1,222) exhibited seroreactivity, defined as a phase II antigen IgG or IgM titer ≥ 1:16. In the multivariate analysis, male sex, residence in Gyeonggi Province, a larger herd size, and ocular/oral contact with birth products during calf delivery were significantly associated with a higher risk of C. burnetii infection. Furthermore, the risk was significantly lower among farmers who always wore protective gloves while cleaning cattle excretion, compared to those who sometimes or rarely wore protective gloves. CONCLUSION: Dairy cattle farmers should exercise caution by avoiding ocular/oral contact with birth products during calf delivery and by using protective equipment (including gloves).

Green Tobacco Sickness Among Tobacco Harvesters in a Korean Village

BACKGROUND: Green tobacco sickness (GTS), an occupational disease in tobacco harvesters, is a form of acute nicotine intoxication by nicotine absorption through the skin from the wet green tobacco plant. We carried out a questionnaire survey and measured cotinine concentration, the metabolic product of nicotine, to determine the prevalence, incidence, and risk factors of GTS in Korean tobacco harvesters. METHODS: We measured cotinine concentrations, and administered a questionnaire survey to tobacco harvesters in Cheongsong-gun, Gyeongsangbuk-do, Korea. We repeatedly measured urine cotinine concentration five times with a questionnaire survey. RESULTS: Cotinine concentration at dawn was significantly higher than that at other times; it was significantly lower during the nonharvesting period than during the harvesting period. However, little change in cotinine concentration was detected in the daytime during the harvesting period. Study participants included 20 men and 20 women. The prevalence of GTS was 37.5% and was significantly higher in women than in men (55.0% vs. 20.0%, p < 0.01). GTS incidence according to number of workdays was 3.4 occurrences/100 person days. CONCLUSION: In this study, nicotine exposure and metabolism were experimentally determined from the time of cotinine exposure, and biological monitoring was performed in each season. In the future, this information may be valuable for medical decision-making in GTS prevention.

Seroreactivity to Q Fever Among Slaughterhouse Workers in South Korea / 예방의학회지

OBJECTIVES: Q fever is a zoonotic disease that occurs worldwide; however, little is known about its prevalence in South Korea. We attempted to determine the prevalence of Q fever seroreactivity among Korean slaughterhouse workers and the risk factors for seroreactivity according to the type of work. METHODS: The study was conducted among 1503 workers at a total of 73 slaughterhouses and 62 residual-product disposal plants. During the study period, sites were visited and surveys were administered to employees involved in slaughterhouse work, and serological tests were performed on blood samples by indirect immunofluorescence assays. Serological samples were grouped by job classification into those of slaughter workers, residual-product handlers, inspectors and inspection assistants, and grading testers and testing assistants. Employee risk factors were analyzed according to the type of work. RESULTS: Out of 1481 study subjects who provided a blood sample, 151 (10.2%) showed reactive antibodies. When these results were analyzed in accordance with the type of work, the result of slaughter workers (11.3%) was similar to the result of residual-product handlers (11.4%), and the result of inspectors and assistants (5.3%) was similar to the result of grading testers and assistants (5.4%). Among those who answered in the affirmative to the survey question, “Has there been frequent contact between cattle blood and your mouth while working?” the proportions were 13.4 and 4.6%, respectively, and this was identified as a risk factor that significantly varied between job categories among slaughterhouse workers. CONCLUSIONS: This study found a Q fever seroreactivity rate of 10.2% for slaughterhouse workers, who are known to be a high-risk population. Contact with cattle blood around the mouth while working was the differential risk factor between job categories among slaughterhouse workers.

Necessity of a Surveillance System for Tick-borne Encephalitis

No abstract available.

Respiratory Syncytial Virus Outbreak in the Basic Military Training Camp of the Republic of Korea Air Force / 예방의학회지

OBJECTIVES: An outbreak of acute febrile illness occurred in the Republic of Korea Air Force boot camp from May to July 2011. An epidemiological investigation of the causative agent, which was of a highly infective nature, was conducted. METHODS: Throat swabs were carried out and a multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) assay was performed to identify possible causative factors. RESULTS: The mean age of patients who had febrile illness during the study period was 20.24 years. The multiplex RT-PCR assay identified respiratory syncytial virus (RSV) as the causative agent. The main symptoms were sore throat (76.0%), sputum (72.8%), cough (72.1%), tonsillar hypertrophy (67.9%), and rhinorrhea (55.9%). The mean temperature was 38.75degreesC and the attack rate among the recruits was 15.7% (588 out of 3750 recruits), while the mean duration of fever was 2.3 days. The prognosis was generally favorable with supportive care but recurrent fever occurred in 10.1% of the patients within a month. CONCLUSIONS: This is the first epidemiological study of an RSV outbreak that developed in a healthy young adult group. In the event of an outbreak of an acute febrile illness of a highly infective nature in facilities used by a young adult group, RSV should be considered among the possible causative agents.

Analysis of the Change of Health Status Among the Republic of Korea Air Force Soldiers During Military Service / 예방의학회지

OBJECTIVES: The aim of this study was to investigate whether the health status of Republic of Korea Air Force (ROKAF) soldiers changed after one year of military service. METHODS: We selected 483 ROKAF soldiers from the 11 749 recruits who participated in the 2011 physical examination. The selected soldiers underwent another physical examination in 2012 for advancement to senior airman. Data from 2011 and 2012 were merged. To collect data on lifestyle, a questionnaire was sent to all included subjects via the military intranet e-mail service. RESULTS: The percentage of recruits with an abnormal alanine transaminase level (normal range or =25 kg/m2) decreased from recruitment (20.5%) to the following year (10.4%). There was a significant change in mean duration of exercise carried out each day before (0.8+/-1.3 hours) and after (1.0+/-0.7 hours) joining the ROKAF service. CONCLUSIONS: These ROKAF soldiers were generally in good health before and after joining the armed service. After one year of military service, the health status of most soldiers improved, especially with respect to body mass index and alanine transaminase level.

Awareness on Zoonoses among Pig Farmers in Korea / 農村醫學 地域保健

OBJECTIVES: Pig farmers are known as the high risk group for the zoonoses, but the study for pig farmers to zoonoses has been rare in Korea. So we surveyed the awareness on zoonoses among pig farmers to suggest directions for education. METHODS: We visited four regional spots (Gyeongsangnam-do, Gyeongsangbuk-do, Jeollanam-do, and Chungcheongnam-do) where the self education programs of Korea pork producers were convened. We conducted a questionnaire survey of the general, work-related characteristics and the awareness on zoonoses among 278 pig farmers. RESULTS: The awareness rate of zoonoses itself, brucellosis, tuberculosis and salmonellosis were 52.9%, 85.6%, 87.8%, 89.6%, respectively. The awareness rate of the content related to zoonoses, "Human can be infected by the disease of pig", was 46.9%. Awareness rate of zoonoses tended to increase as the school career, and awareness rate of salmonellosis tended to increase as working duration of pig raising. CONCLUSIONS: The pig is the principal reservoir of zoonoses. Therefore, effective working guidelines to prevent zoonoses for pig farmers must be developed and an educational program on zoonoses is needed for pig farmers. Furthermore, publicity activities about the prevention of zoonoses are needed for high-risk groups.

Airborne Nicotine Concentrations in the Workplaces of Tobacco Farmers / 예방의학회지

OBJECTIVES: Nicotine is a natural alkaloid and insecticide in tobacco leaves. Green tobacco sickness (GTS) is known as a disease of acute nicotine intoxication among tobacco farmers. Until now, GTS has been recognized globally as a disease that results from nicotine absorption through the skin. However, we assumed that GTS might also result from nicotine inhalation as well as absorption. We aimed to measure the airborne nicotine concentrations in various work environments of Korean tobacco farmers. METHODS: We measured the nicotine concentrations in the tobacco fields, private curing barns, and joint curing barns of farmers from July to October 2010. All sampling and analyses of airborne nicotine were conducted according to the National Institute for Occupational Safety and Health manual of analytic methods. RESULTS: The airborne nicotine concentrations (geometric mean [geometric standard deviation]) in the tobacco field were 83.4 mg/m3 (1.2) in the upper region and 93.3 mg/m3 (1.2) in the lower region. In addition, the nicotine concentration by personal sampling was 150.1 mg/m3. Similarly, the nicotine concentrations in the private curing barn, workers in curing barns, the front yard of the curing barn, and in the joint curing barn were 323.7 mg/m3 (2.0), 121.0 mg/m3 (1.5), 73.7 mg/m3 (1.7), and 610.3 mg/m3 (1.0), respectively. CONCLUSIONS: The nicotine concentration in the workplaces of tobacco farmers was very high. Future studies should measure the environmental concentration of nicotine that is inhaled by tobacco farmers.

Epidemiological Investigation of an Outbreak of Salmonellosis in Gyeongju, Korea / 예방의학회지

OBJECTIVES: A salmonellosis outbreak occurred within a community of Gyeongju residents who ingested catered food from a wedding in June 2009. We aimed to epidemiologically investigate the probable vehicle of the infection. METHODS: We conducted a retrospective cohort study on 34 local residents who ingested the wedding food. RESULTS: Among the 34 residents, 31 (91.2%) reported symptoms of infection after eating the food. Among all of the wedding foods, pan-fried foods were highly associated with the diarrheal attack rate. On bacteriological examination, Salmonella species were detected in the pan-fried foods among the leftover foods and in 17 of the 31 stool specimens from the cases. There were five different types of pan-fried foods, but the onset of symptoms was independent of the ingredients used. We found that the pan-fried food was prepared at a food store in Seoul and that eggs were a common ingredient. CONCLUSIONS: The major cause of the salmonellosis in this population was presumed to be the pan-fried food prepared with contaminated eggs. These food items might have been partially undercooked because of their irregular shape, which allowed the Salmonella species to survive and multiply before ingestion.

Epidemiological Investigation on an Outbreak of Norovirus Infection at a High School in Gyeongju City, 2009 / 農村醫學 地域保健

OBJECTIVES: An outbreak of norovirus occurred at a high school in Gyeongju city in 2009. An epidemiological investigation was carried out to examine the infection source and the transmission route of norovirus, and to prevent a recurrence. METHODS: A questionnaire survey was conducted for 520 male students and 8 food handlers. Rectal swabs were examined in 21 symptomatic students and the 8 food handlers by Gyeongsangbukdo Government Public Institute of Health & Environment, and an environmental investigation was performed. A case-control study was used to evaluate the association between risk factors and disease. RESULTS: The attack rate was 21.3% (111/520) between January 29 and February 10, and norovirus GII was isolated from 12 of 21 students. Food handlers had no symptoms and their stool samples were negative. The case-control study revealed that seasoned soy bean sprouts {odds ratio (OR): 2.542, 95% CI=1.315-4.915} and drinking water from the purifiers in the cafeteria (OR: 2.854, 95% CI=1.107-7.358) supplied on February 3 were significant risk factors for the outbreak. Water pipes and waste pipes were located in the same place where was filled with some water and trace of high water level was detected. CONCLUSIONS: The major risk factors for this norovirus outbreak were presumed to be the contaminated seasoned soy bean sprouts and drinking water from the purifiers in the cafeteria. More strict personal and environmental hygiene need to be enforced to prevent such outbreaks.

Awareness of Zoonoses among Cattle Slaughterhouse Workers in Korea / 農村醫學 地域保健

OBJECTIVES: Cattle slaughterhouse workers are known as the high risk group for the zoonoses. We surveyed the awareness of zoonoses among cattle slaughterhouse workers to suggest direction of education and public relations. METHODS: We evaluated the epidemiological characteristics of zoonoses and the process of cattle slaughtering. We designed different questionnaires for the workers involved in slaughtering, the handlers of residual products, the inspectors and their assistants, and the grading testers and their assistants respectively. We visited 73 cattle slaughterhouses and 62 residual products handle houses across the country and conducted a questionnaire survey of the general characteristics and the awareness of zoonoses. The data collected was evaluated using the SPSS 17.0 statistical package. RESULTS: The awareness rate of brucellosis, Q fever and Enterohemorrhagic Escherichia coli (EHEC) were 83.9%, 18.5%, 62.7% among cattle slaughterhouse workers. The awareness rate of zoonoses among the workers involved in slaughtering and the handlers of residual products was lower than other workers. The awareness rate of zoonoses tended to increase as the school career. In the correct awareness rate of the transmission of zoonoses, 'transmission by tick bite', 'person to person' and 'air transmission' were lower than other transmission items. The most common reason why cattle slaughterhouse workers think that it is difficult to prevent zoonoses was the ignorance of how to prevent. CONCLUSIONS: An educational program is needed for the cattle slaughterhouse workers on zoonoses especially Q fever. And publicity activities about prevention of infection are needed for high risk groups.

Seroprevalence and Risk Factors of Brucellosis among Slaughterhouse Workers in Korea / 예방의학회지

OBJECTIVES: The incidence of zoonoses in Korea has increased recently. However, the study of high risk groups for zoonoses has not been conducted to date in Korea. Thus, we did this study to obtain data on brucellosis among slaughterhouse workers in Korea. METHODS: We evaluated the structure of slaughterhouses and the process of slaughtering by reviewing the relevant literature and doing field studies. We visited 73 slaughterhouses and 62 residual products handle houses across the country. In addition, we conducted a questionnaire survey of the work activities, and obtained blood samples in order to determine the seroprevalence and risk factors of brucellosis. The titers of brucellosis antibodies were measured using the standard tube agglutination test (SAT). We diagnosed subjects as seropositive for Brucellosis if the titers were more than 1:160. The data collected was evaluated using SPSS ver. 17.0. RESULTS: We included 1,503 subjects and obtained 1,482 blood samples among them: 849 workers involved in slaughtering, 351 handlers of residual products, 190 inspectors and their assistants, and 92 grading testers and their assistants. The seroprevalence of brucellosis among the slaughterhouse workers was 0.8% (95% CI=0.4-1.5). Broken down, the seroprevalence of brucellosis among the workers involved in slaughtering was 0.7% (95% CI=0.3-1.6), the handlers of residual products was 1.7% (95% CI=0.7-3.9) respectively. Risk factors for contracting brucellosis among slaughterhouse workers were being splashed with cattle blood around the mouth, cattle secretions around the body and not putting on protective apron while at work. CONCLUSIONS: An educational program is needed for high risk groups on zoonoses about the prevention of infection. Thus, effective working guidelines for workers who participate in the slaughter of animals must be developed in order to protect them from zoonoses.