• Journal of Environmental Health Sciences
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• v.46 no.6
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• pp.710-718
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• 2020

Objectives: We analyzed water in waterscape facilities to investigate contamination levels of water-borne pathogens and four test items (pH, turbidity, residual chlorine, and Escherichia coli) at facilities including play fountains, splash parks, and artificial streams from June to October in Suwon City and in the whole of Gyeonggi-do. Methods: A total of 62 waterscape facility samples were collected from 36 sites and tested for pathogenic Escherichia coli and water-borne viruses that cause hand-foot-and-mouth disease, eye disease, and acute enteritis. Results: None of the water-borne pathogens were detected in waterscape facility samples collected from across Gyeonggi-do that were for pre-inspection for facility management. However, the results of samples from Suwon collected in hot weather and during the school vacation period showed five total inconsistencies in turbidity (four cases) and Escherichia coli (one case). Three out of the four inconsistent samples in turbidity were from the same facility which operated a sand filtration system due to its locational factors close to mountains. Conclusion: We suggest that the waterscape facilities in Gyeonggi-do are managed properly in the respect of microbial contamination and water quality.

• Korean Journal of Environmental Biology
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• v.20 no.3
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• pp.189-196
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• 2002

The direct detection of intestinal pathogens and viruses often requires costly, tedious, and time-consuming procedures. These requirements developed a test to show that the water was contaminated with sewage-borne pathogens by assessing the hygienic quality of water based on indicator microorganisms whose presence indicates that pathogenic microorganisms may also be present. Various groups of microorganisms have been suggested and used as indicator microorganisms. Proposed and commonly used microbial indicators are total coliforms, fecal coliforms, fecal streptococci, Clostridium perfringens, heterotrophic plate count, bacteriophage, and so on. Unfortunately, most, if not all, of these indicators are not ideal because of the sensitivity and resistance to environment stresses and disinfection. However, the development of gene probes and PCR technology may give hope for the discovery of rapid and simple methods toy detecting small number of fecal pathogens in various environments.

• Journal of Environmental Health Sciences
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• v.45 no.5
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• pp.434-442
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• 2019

Objectives: This study was performed in order to report the epidemiological features of a food poisoning outbreak caused by multiple pathogens in a high school in Chungcheongnam-do Province, Korea in April 2019 and to suggest measures to prevent a similar incidence. Methods: A total of 39 patients with diarrhea were examined. Environmental samples were obtained from 6 food handlers, 4 food utensils, 72 preserved foods served during the food poisoning outbreak, 9 door handles, 10 drinking water samples from water dispensers, and 6 ground water samples from water taps. These analyzed to detect viruses and bacteria. Results: Among the 39 patients, 21 cases (53.8%) of enteroaggregative E. coli (EAEC), 7 cases of Staphylococcus aureus (17.9%), and 17 cases of norovirus (43.6%) were positive, and in 16 of the cases a co-infection with at least one other pathogen were observed. EAEC was assumed to be transmitted from contaminated drinking water because it was also detected in the water sample from a water dispenser in the dormitory. Staphylococcus aureus was isolated only in the fecal samples of patients, meaning it was not possible to trace its origin. The genotype of norovirus detected in the drinking water and ground water was consistent with that isolated from patients, and it was determined that the norovirus infection originated from the school's water environment. Conclusions: These findings indicate that a lack of environmental hygiene management related to school meals caused the food poisoning incident. In particular, a lack of management of drinking water, water supply, and personal hygiene should be pointed out. This should be urgently addressed and continuous monitoring should be carried out in the future. In addition, students and staff should be educated and trained to improve their personal hygiene.

• Korean journal of applied entomology
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• v.57 no.4
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• pp.415-423
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• 2018

Aphid is a typical vector that transfers various kinds of viruses to potatoes. Therefore, it is very important to control aphids moving into potato fields. We investigated the seasonal movement pattern of aphids and its virus transmission rates mainly in the three seed potato production regions at highland in Gangwon-do, Korea. In addition, we identified the aphid species with over-wintering eggs collected from barks or twigs of total 57 tree species around potato fields in winter season. The peak time of summer and winter migration of aphid was at the mid-June and the early October, respectively. A 2.8% of total aphid trapped in yellow water-pan trap was turned out PLRV-borne, and the virus transmission rate was 15.4% by Myzus persicae and 9.1% by Macrosiphum euphorbiae. PLRV-borne aphids started to flow in from the late May, and virus transmission rate of aphid trapped in mid-June was the highest with 10.4%. Totally 14 species of aphid eggs wintered in the 17 species of trees including Acer pictum subsp. mono and Acer pseudosieboldianum at the 11 sites. In particular, because it is not certain that Betula platyphylla var. japonica and Yamatocallis hirayamae do transmit potato virus, but they over-wintered in host plants distributed over a wide area, further research on transmission ability is necessary.

• Journal of Life Science
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• v.30 no.2
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• pp.178-185
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• 2020

Rice bakanae is a typical seed-borne and seed-transmitted disease caused by infection by Fusarium fujikuroi. Seed disinfection using chemical fungicides (such as benomyl and prochloraz) is most effective in controlling the disease, but the emergence of fungicide-resistant strains has recently been increasing. Slightly acidic hypochlorous acid water (SAHW) is a safe and environmentally friendly disinfectant that has a potent and broad spectrum of antimicrobial activity against viruses, bacteria, and fungi. In this study, we aimed to investigate the effectiveness of SAHW against F. fujikuroi strains, including chemical fungicide-resistant strains, as an alternative to conventional chemical fungicides in the management of bakanae disease. SAHW showed strong but similar levels of antifungal activity among the F. fujikuroi strains with a minimum inhibitory concentration (MIC₉₀) of 5±2.5 ppm of free available chlorine (FAC). In addition, F. fujikuroi cells lost viability completely within 5 min of SAHW treatment due to the lethal damage to cell integrity. When the rice seeds infected by F. fujikuroi were treated with SAHW containing 20±10 ppm of FAC for 12 hr, the efficiencies of seed disinfection and disease control were 95-98% and 90.1-92.6%, respectively. Altogether, our data suggest that SAHW is an effective compound for controlling rice bakanae disease.

• Journal of Environmental Health Sciences
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• v.46 no.5
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• pp.525-531
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• 2020

Objectives: This study was performed to identify the epidemiological features of a food poisoning outbreak in a company cafeteria located in Chungcheongnam-do Province, Korea in June of 2020 and to suggest preventive measures for a similar incidence. Methods: A total of 84 patients with acute gastroenteritis were examined. Environmental samples were obtained from 16 food handlers, six food utensils, 135 preserved foods served over three days and nine menus, and six drinking water samples. These are analyzed to detect viruses and bacteria. Results: Ninety-four out of the 402 people who were served meals (23.4%) predominantly showed symptoms of diarrhea, and the number was over 3 times. Among the 84 patients under investigation, 17 cases (20.2%) were positive for Enteropathogenic E. coli (EPEC) and 18 cases were positive for Clostridium (C.) perfringens (21.4%). Based on the investigation, it was concluded that the main pathogens were EPEC and C. perfringens. For EPEC, it was detected in three of the food service employees and in the preserved food and curry rice. The results of pulsed field gel electrophoresis indicate that all EPEC cases are closely related except for one food service employee. Assuming that isolated EPEC originated from the preserved food, the incubation period is about 25 hours. The origin of the C. perfringens was not determined as it was not detected in the food service employees or environmental samples. Conclusions: This case suggests that food provided in group food service centers must be thoroughly managed. In addition, identifying the pathogens in preserved food is very important for tracing the causes of food poisoning, so food must be preserved in an appropriate condition. To prevent similar food poisoning cases, analyzing cases based on epidemiological investigation and sharing the results is needed.

• Research in Plant Disease
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• v.10 no.3
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• pp.188-193
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• 2004

The symptom expressions such as yellowish and mosaic spots in overwintering barley have been considered to be a damage by cold or water. However, it had revealed that the symptom expressions were caused by viruses throughout three year nationwide surveys. Barley yellow mosaic virus (BaYMV), Barley mild mosaic virus (BaMMV), and Soil-borne wheat mosaic virus (SBWMV) was detected in 2001-2003 and Barley yellow dwarf virus-MA V (BYDV -MA V) from field samples collected on March in 2003. The results of investigation showed that the incidence of BaYMV was more than 70％ and that of BaMMV and SBWMV was 15.7-37.4％ and 0.7-10.1 ％ in three year surveys, respectively. The incidence of BYDV-MAV was approximately 1 ％ in 2003 only. The distribution of BaYMV was relatively uniform throughout barley fields in Korea, but the incidence of the virus in Gyunggi Province was as low as 19％ compared to 65-85％ in the rest of regions. On the other hand, 70％ of BaMMV was found to be in the west south regions of Korea, Jeonbuk and Jeonnam Provinces. Taken together, both BaYMV and BaMMV were thought to be dominant casual agents in overwintering barley by either single or mixed infections. Previous survey data for BaYMV from 1994 to 1996 indicated that the incidence of the virus was approximately 40％ in Jeonbuk, Jeonnam, and Gyungnam Provinces. Thus, comparing with the results from the recent nationwide survey, the incidence of BaYMV had been rapidly increasing in overwintering barley fields in the southern part of Korea.