• Parasites, Hosts and Diseases
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• v.33 no.1
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• pp.27-36
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• 1995

Comparative epidemiological studies on vector reservoir animals of tsutsugamushi disease were carried out in between south coast (the highest endemic) areas and east coast flow endemicl areas in October 1993. Fauna of field rodents and their population densities were not different between two areas. Antibody positive rate of Apodemus agrarius sera was higher in east coast (43.2% in south coast and 63.6% in east coast). High correlation (r = 0.87) was shown between antibody positive rate of A. osrwiur sera and population density of the vector mites (Leptotrombidium scutellare and 1. pnllidunl). L. scutellare was predominant in south coast, showing 110.6 chigger index (74.9% of the total chiggersl , whereas L. pcllidum was predominant in east coast, showing 126.3 chigger index (60.4% of the total). As higher population density of 1. scutellare was found in south coast where the prevalence rate of tsutsugamushi disease is the highest, it is believed that L. scutellare is more important vector species than L. pallidum which may result from more frequent vector-human contact.

• Journal of the Korean Society of Radiology
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• v.85 no.3
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• pp.682-690
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• 2024

Acute necrotizing encephalopathy (ANE) is a rare immune-mediated complication of a viral infection commonly involving the bilateral thalamus and has been reported mainly in children. Here, we describe the MRI findings of coronavirus disease 2019 (COVID-19)-associated ANE in two pediatric patients, including a 7-year-old girl with fever and mental change, and a 6-year-old girl with fever and generalized seizures. Brain MRI revealed symmetrical T2 fluid attenuated inversion recovery high-signal intensity lesions in the bilateral thalamus with central hemorrhage. In one patient, the thalamic lesions showed a tri-laminar pattern on the apparent diffusion coefficient map. This report emphasizes the importance of creating awareness regarding these findings in patients with COVID-19, particularly in children with severe neurological symptoms. Furthermore, it provides a literature review of several documented cases of COVID-19 presenting with bilateral thalamic hemorrhagic necrosis, suggesting a diagnosis of ANE.

• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.113-120
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• 1986

Soybeans collected from different locations in Korea were planted for tests of seed transmission of soybean mosaic virus (SMV). The percentage of seed transmission ranged from 20.5 to 29.5% in 14 seedlots including soybean cultivar Namhe and 12 to 19% in other 44 seedlots. However, no seed transmission of SMV was observed in soybean cultivar Younkiyongho. SMV was detected from embryo and cotyledon of soybean seeds. The infection of SMV was highly detected from premature seeds than from fully mature seeds, and higher from seeds harvested from plants infected before June 20 than plants infected around July 20 and August 20. No significant relationship was observed between seed transmission of SMV and mottling of seeds. The incidence of soybean mosaic disease followed by one month after peak of aphid population. The number of aphids was less on leaves of soybeans with short and dense trichomes whereas it was higher on leaves of soybean with long and sparse trichomes. Generally, the number of aphids was decreased on leaves with long and dense trichomes as the growth progressed. Soybean cultivar Columbus and 14 cultivars were susceptible, Chief and 14 cultivars were moderate, but Jangbaek and 17 other cultivars were resistant to SMV when inoculated with one isolate of SMV.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.419-423
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• 2015

Small brown planthopper (SBPH), Laodelphax striatellus, gives a lot of damage to the rice by insect vector of rice stripe virus (RSV). This study compared the RSV acquisition and infection rates according to wing form, sex, and life stage of SBPH. The RSV acquisition rate in macropterous and brachypterous was 60.7% and 63.1%, respectively. The RSV acquisition rate by sex was 61.9% in female and 52.2% in male. However, there was no difference in significance. The RSV acquisition rate of nymphs and adults was 51.2% and 58.7%, respectively. The RSV infection rate by wing form was 53.3.% in macropterous and 48.2% in brachypterous. According to life stage, nymphs was 38.2% and adults was 42.6%. There was no difference in significance. On the other hand, female and male of RSV infection rate was 50.5% and 22.3%, respectively. There was a significant difference. Additionally, developmental periods of SBPH by RSV infection, the longest when inoculated with RSV-infected SBPH in healthy rice, while the shortest when inoculated healthy SBPH in healthy rice.

• Korean journal of applied entomology
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• v.20 no.3 s.48
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• pp.135-145
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• 1981

Vegetables including Chinese cabbage and radish have been grown in alpine areas such as Muju, Namweon, Jinan and Jangsu during the shortage period of vegetables. The incidence of various diseases, environmental factors such as temperatures and rainfalls, and aphid populations as virus vector were observed at 10-day intervals from July to September in those areas. Disease incidence showed no significant difference among locations. Major diseases in Chin ese cabbage were bacterial soft rot, white spot, downy mildew, mosaic virus, Alternaria leaf spot and Fusarium seedling blight. Major diseases in radish were virus, white rust, black rot, root rot, leaf spot and Fusarium seedling blight. Disease incidence reached peak on Aug. 20 with $27\%$ infection in radish and with $20\%$ infection in Chinese cabbage during the growing season, and declined thereafter. Percentage of infection in each growth stage showed $25\%$ at root thickening stage and $26\%$ at the harvest time in radish; and the head formation stage, $24\%$ at the harvest time. The data indicate that disease incidence in radish increased rapidly at late growing stage and progressively increased in Chinese cabbage Seedling blight caused by Fusarium sp. and root rot caused by Aphanomyces sp. were also observed in those areas. Cool and wet weather appeared to be favorable for disease incidences during the rainy period of growing season although average temperature was about $25^{\circ}C$. Populations of aphids were lower in the alpine vegetable growing area than that of flat areas. Aphids as virus vectors from total aphids collected were $73.5\%$ or 289 virus vectors /993 total aphids in Namweon and $18.1\%$ or 31 virus vectors/171 total aphids in Muju. The most prerevalent species of aphids was Myzus persicae Sulz.

• Research in Plant Disease
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• v.16 no.2
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• pp.115-120
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• 2010

In this study, changes in virus disease occurrence and yield were monitored in conventional cropping system(rice-barley) and soybean-barley double cropping system in virus-prone area for 5 years. Also, changes in the density of Polymyxa graminis, a fungal vector, was investigated. In assay tests, mixed infection of Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV) was observed. Disease severity was in the range of 7~9 in conventional cropping system. In continuous cropping of soybean-barley and 3-yearfallow land, disease severity also was around 7. However, disease severity was reduced to medium level (5) when barley cultivation was paused for one or two years in soybean-barley cropping. When barley cultivation was paused for a year, the density of P. graminis, a fungal vector for BaYMV and BaMMV, reduced in barley root and soil. Similarly, barley growth was also enhanced by adopting fallow seasons. Compared with the fifth year of conventional cropping, the number of tillers per $m^2$ was increased by 158 when barley cultivation was paused for an year in soybean-barley cropping. When soybean and barley were cultivated continuously or complete fallow period was extended to three years, plant height and the number of tillers of barley were decreased. Yield components of barley in soybean-barley cropping were superior to those in rice-barley cropping. Compared with the fifth year of conventional cropping and soybean-barley cropping, culm length of barley was 1.3~2.3 cm higher and the number of tillers per $m^2$ was 36~90 higher when barley cultivation was paused for one or two years. However, those in continuous cropping of soybean-barley and 3-year-fallow land were lower compared with conventional cropping. Similarly, yield was increased when barley cultivation was paused for one or two years in the third, forth, and fifth years when compared with conventional cropping.

• Tuberculosis and Respiratory Diseases
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• v.39 no.1
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• pp.62-72
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• 1992

Background: T-cell mediated cellular immunity has been suggested as an important mechanism in mycobacterial infection and imbalance between helper/inducer and suppressor/cytotoxic T-cell has been suggested as an important immunological abnormality in the pathogenesis of tuberculosis in human. Method: To determine whether there is any difference in T-cell mediated immunity in the pathogenesis of pulmonary and extra pulmonary tuberculosis, total numbers of WBC&lymphocytes were counted and helper/inducer and suppressor/cytotoxic cells were calculated by flow cytometry. Blastogenesis after stimulation with Concanavalin-A, Phytohemagglutinin and PPD were measured by $^3H$-thymidine uptake. PPD skin test was performed as an in vivo test. Results: 1)There was no significant difference in the size of PPD skin test between pulmonary and extrapulmonary tuberculosis groups. 2)Number of total lymphocytes significantly decreased in tuberculosis patients compared with healthy control group. But there was no significant difference between pulmonary and extrapulmonary tuberculosis groups. 3) Number of HLA-DR and Interleukin-2 receptor (+) cells were significantly increased in tuberculosis patients. But there was no significant difference between pulmonary and extra pulmonary tuberculosis groups. 4) There was no significant difference in the numbers of WBC, $T_3$, $T_4$ and $T_8$ lymphocytes and $T_4/T_8$ ratio between tuberculosis patients and healthy controls. 5) There was no significant difference in the blastogenesis after stimulation with specific and non-specific blastogens between tuberculosis patients and healthy controls. 6) The percentage and absolute number of $T_4$ lymphocyte were significantly correlated with the size of PPD skin test. (r=0.689 and 0.598). Conclusion: From these results, it is concluded that there was no difference in T-cell mediated immunity between pulmonary and extra pulmonary tuberculosis group. But, because it is suspected that there might be some difference in the role of T-cell mediated immunity in the pathogenesis of pulmonary and extra pulmonary tuberculosis or even among the extrapulmonary tuberculosis patients, further studies would be required.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.591-594
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• 2009

Acute and massive death was noted in 10-week-old chickens, broiler breeder, housed in the floor pens. The number of dead chickens exceeded 20 birds each day. Grossly, fibrinous peritonitis with adhesion of mesenteries and intestinal organs was noted. The ceca were enlarged, expanded, and thickened with congestion. Cecal lumen was distended with a caseous core composed of serous, fibrinopurulent, and hemorrhagic exudates with desquamated masses of epithelial cells. The liver had multifocal white irregular necrotic foci surrounded by a raised ring. Light and electron microscope revealed Histomonas meleagridis in the liver with its characteristic structures and not in the intestinal mucoca and submucosa. In this case, the examination of parasite, larvae and egg was conducted more carefully; however, we could not find eggs or worms of Heterakis gallinarum in the dead or live chickens and earthworms in the soils of floor pens. Therefore, we concluded that an outbreak of blackhead disease probably occurred by direct transmission of histomonads from chickens to chickens in this case.

• Parasites, Hosts and Diseases
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• v.33 no.4
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• pp.383-386
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• 1995

Schistosomiasis is a snail-transmitted trematodiasis acquired by immersion in water which contains the cercariae. In Korea, six imported cases of urinary schistosomiasis by Schistosomc haematobium and one case of imported cerebral schistosomiasis by S. mansoni were reported. Herein we report a case of S. monsoni infecting rectum of a 46 year-old Korean male, who had been to Saudi Arabia for two years. On colonoscopy for routine physical check up, a 0.4 cm polyp in the rectum was detected and biopsy was done. Microscopically, rectal mucosa showed several granulomas which were composed of macrophages, Iymphocytes, neutrophils and eosinophils. The center of each granuloma showed an ovoid egg often containing miracidium. The eggs measured 130 × 60 ㎛ in average size. They had yellowish-brown transparent shell loth the characteristic lateral spille. This is the 8th imported case of schistosomiasis in Korea and the second one infected by S. mansoni. Key words: Schistosomc mansoni, rectum, Korea, imported case.

• Journal of agricultural medicine and community health
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• v.43 no.4
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• pp.258-269
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• 2018

Objectives: There was an outbreak of foodborne and waterborne disease among high school students at Okcheon in June, 2018. First attack occurred June $5^{th}$ but seven days later it was notified. The purpose of this investigation was to evaluate the pathogen of outbreak and cause of delayed notification. Methods: First, we did a questionnaire survey for 61 cases and 122 controls to find what symptoms they had and whether they ate foods or drank water from June $2^{nd}$ to June $12^{th}$. Second, we investigated the environment of cafeteria and drinking water. Third, we examined specimen of cases and environment to identify bacteria or virus. Results: Attack rate of this outbreak was 7.8%. Drinking water was strongly suspected as a source of infection in questionnaire survey but we could not find the exact time of exposure. Norovirus was identified in specimen of cases (2 students), drinking water (at main building and dormitory) and cafeteria (knife, dishtowel, hand of chef) Conclusions: We decided norovirus as the pathogen of this outbreak based on the clinical features of cases with diarrhea vomiting, abdominal pain and recovery within 2 or 3 days after onset, outbreak due to drinking water and microbiologic examination, And the cause of delayed notification might be the non-existence of the nurse teacher at that time and the lack of understanding of teachers on immediate notification under the outbreak. To prevent the delayed notification, notification system about outbreak of foodborne and waterborne disease in school is needed to be improved.