• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.1
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• pp.41-46
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• 2014

Purpose: The spontaneous seroconversion rate of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) virus infection in children is lower than that in adults. However, few studies have investigated the rate of transition from the immune-tolerant to the early immune-clearance phase in children. Methods: From February 2000 to August 2011, we enrolled 133 children aged <18 years who had visited the Department of Pediatrics, Kyungpook National University Hospital. All subjects were in the immune-tolerant phase of HBeAg-positive CHB virus infection. The estimated transition rate into the early immune-clearance phase was calculated using the Kaplan-Meier method. Results: Among the 133 enrolled pediatric CHB virus infection patients in the HBeAg-positive immune-tolerant phase, only 21 children (15.8%) had converted to the early immune-clearance phase. The average age at entry into active hepatitis was $10.6{\pm}4.8$ years. The incidence of transition from the immune-tolerant to the early immune-clearance phase in these children was 1.7 episodes/100 patient-years. When analyzed by age, the estimated transition rate was 4.6%, 7.1%, and 28.0% for patients aged <6, 6-12, >12 years, respectively. Conclusion: In children with CHB virus infection, the estimated rate of entry into the early immune-clearance phase was 28.0% for patients aged 12-18 years, which was significantly higher than that observed for children aged <12 years (11.7%; p=0.001).

• Journal of Korean Academy of Nursing
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• v.29 no.3
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• pp.614-624
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• 1999

The purpose of this study is to determine the effectiveness of routine meatal care on the reduction of catheter-associated urinary tract infection (UTI). The study was carried out on 30 patients with foley catheters in an intensive care unit of a general hospital from September 30 to April 1, 1998. Participants were both male and female. Data were collected from each patients by urinary specimen obtained with aseptic collection technique at the 3rd and the 7th day of the experiment after giving daily mental care with 10% betadine for periods ranging from 1st to 7th day to the experimental group but not to the control group. The results are as follows : 1. The rate of urinary tract infection within the experimental group was 0.0%, at the 3rd day of the experiment and 20.0% at the 7th day, but that of the control group was 20.0% at the 3rd day and 7% at the 7th day. There was a significant difference in urinary tract infection rate between the two groups at the 3rd day but no significant difference at the 7th day. 2. In the control group, the rate of UTI was 0.7% for male and 13.3% for female at the 3rd day, and 6.7% for male and 40% for female at the 7th day. In the experimental group, the rate of UTI was 6.7% for male and 0.0% for female at the 3rd day and 13.3% for male and 20% for female at the 7th day of experiment. There was a no significant difference between male and female. 3. By comparing the rate of UTI to the length of time the urinary catheter was in place, the longer the catheter was in place the more significant was the rate of UTI. 4. Microorganisms isolated in the control group were bacteria for 7 cases and fungus for 3 cases but in the experimental group, only 2 cases of bacteria were isolated.

• Journal of agricultural medicine and community health
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• v.8 no.1
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• pp.66-80
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• 1983

As a part of the epidemiological studies of clonorchiasis in Korea, this study was conducted to evaluate the current endemicity and the natural transition of the Clonorchis infection in Goyang Gun a low endemic area in recent years, prior to the introduction of praziquantel which will eventually influence to the status of the prevalence. The data obtained in this study in 1983 were evaluated for natural transition of the infection in comparison with those obtained 16 years ago in 1967 by the author (Kim, 1974). The areas of investigation, villages and schools surveyed, methods and techniques used in this study were the same as in 1967, except for the contents of the questionnaire for raw freshwater fish consumption by the local inhabitants. 1) The current prevalence rate of Clonorchis infection among the inhabitants was 7.5% on the average out of a total of 479 persons examined. The prevalence rate was 9.0% in the riverside area and 4.2% in the inland area. Among the schoolchildren, the prevalence rate was 1.1% out of a total of 1 319 examined. By area, it was 1.4% in the riverside area and 0.7% in the inland area. By sex, the prevalence rate was 13.3% in the male and 1.3% in the female in the inhabitants and no difference was seen in the schoolchildren. 2) In the natural transition of the infection, the prevalence rate in the inhabitants has decreased from 22.5% in 1967 to 7.5% in 1983, and in the schoolchildren, from 9.5% in 1967 to 1.1% in 1983. The reduction rate was higher in the riverside area than in the inland area. 3) In the prevalence rate by age, 1.2% was seen in the 10-14 age group and gradually increased to 8.1% in the 30-39 age group and reached peak 18.1% in the 40-49 age group. By sex, in the male, the prevalence rates have increased to 31.9% and 33.3% in the 40-49 and 50-59 age groups, respectively and decreased thereafter. In the female, the prevalence rate less than 5% was seen only in between the 10-14 and 30-39 age groups. 4) In the natural transition of the prevalence rate by age, sharp decrease was seen in the male from around 50% in 1967 between 15-19 and 30-39 age groups. The generation over 40s showed less decrease. In the female, the prevalence rate has decreased from 13% in 1967 to 5% in 1983 in the middle age groups and dropped to 0% in the rest of the age groups. 5) The intensity of the infection among clonorchiasis cases by mean EPmg (number of eggs per mg feces) value was 1.4. In the inhabitants, the value was 2.0 in the riverside area and 0.4 in the inland area. While in the schoolchildren, the value was 0.2 in both riverside and inland areas. 6) In the transition of the intensity of the infection, EPmg among the inhabitants has decreased from 3.9 in 1967 to 2.0 in 1983 in the riverside area, and from 2.9 to 0.4 in the inland area. In the schoolchildren, the reduction was similar in both riverside and inland areas resulting from 1.0-1.1 in 1967 to 0.2 in 1983. 7) In the intensity of the infection by age, EPmg 3.4 was peak at the 40-49 age group and 0.2-1.0 was seen in the rest of the age groups. The mean value was 1.5 in the male and 0.6 in the female. 8) In the natural transition of the intensity of the infection, the EPmg has decreased from 2.7 in 1967 to 1.4 in 1983. By age, reduction was seen in all of the age groups, particularly in the young and the old age groups of 50s and over, except in the 40-49 age group in which reverse phenomenon was seen. By sex, it has decreased from 3.5 in 1967 to 1.5 in 1983 in the male and from 1.0 to 0.6 in the female. 9) In the distribution of the clonorchiasis cases by the range of EPmg value, 70.3% of the cases were placed in the range of 0.1-0.9 as the most and 16.2% in 1.0-4.9 as the next. With such figures, those included in the range less than 0.9 as light infection were 78.4% and under 5.0-9.9 up to moderate infection 99.3% of the cases were covered. The cases were distributed up to 20.0-39.9 in the male and to 1.0-4.9 in the female. 10) In the transition of the distribution of the clonorchiasis cases by EPmg, the highest intensity reached up to 60.0-79.9 in 1967 and to 20.0-39.9 in 1983. In the range of light infection, under 0.1-0.9, the distribution in rate was 64.5% in 1967 and 78.4% in 1983. Up to the range of moderate infection, under 5.0-9.9, 91.7% in 1967 and 97.3% in 1983 were seen respectively. 11) In a survey for raw freshwater fish consumption among the local inhabitants,78.3 of the clonorchiasis cases interviewed admitted their experience of the raw consumption. However, those who practised in the past two years were 34.8% 55.6% of those who have such experience in the past professed that they did not practise raw freshwater fish consumption in the past two years. 12) The major cause of the reduction of the raw freshwater fish consumption among the inhabitants were the wide spread water pollution in the locality. The most common reason professed for stopping raw freshwater fish consumption among the inhabitants was the risk of the fluke infection. 13) In animal survey, 3.1% of dogs were found infected with Clonorchis, decreasing from 21.6% in 1967. 14) The distribution of the first intermediate host, Parafossarulus manchouricus has greatly diminished in this locality and found only in two localized ponds. No Clonorchis infection was found from the snails examined. 15) The second intermediate freshwater fish host has been further limited by extended water pollution. No susceptible fish host could be examined. 16) In conclusion, the endemicity of Clonorchis infection in Croyang Gun, low endemic area, has significantly decreased during the past 16 years. The major cause of the regressive transition of the infection was the water pollution of the freshwater system of this locality. This has upset the ecosystems of the intermediate host of Clonorchis sinensis in many areas of waterbodies and further discouraged to a significant extent the local inhabitants from raw freshwater fish consumption.

• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.55-75
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• 1974

Transovarial transmission of cytoplamic polyhedrosis virus in the silkworm was studied by observing the phenomena of induction, interference and virulence enhancement in the larvae from moths inoculated with hexagonal Polyhedra of cytoplasmic polythedrosis virus. The experimental results obtained are as followings. 1. The effect of inoculation with tetragonal polyhedra of cytoplasmic polyhedrosis virus on the rate of infective induction with hexagonal polyhedron virus and with hexagonal plus tetragonal polyhedron viruses in the larvae from moths infected with hexagonal polyhedron virus was studied. Infection rate was higher by 40 to 60 percent in the larvae from infected female group than in tile larvae from noninfected female group. 2. In the studies of the effect of formalin-feeding on the induction of infection with hexagonal polyhedron virus, infection rate was higher by 40 percent in the larvae from infected female group than in the larvae from noninfected female group. However, there was no significant difference in the infection rates between the two formalin-concentration groups. 3. The effect of cold treatment on the induction of infection with hexagonal polyhedron virus was studied. Infection rate was higher by 50 percent in the larvae from infected female group than ill the larvae from noninfected female group. No difference was found in the infection rates of the two treatment groups of 12 and 48 hours. 4. The phenomena of induction and interference were studied by observing rate of infection with hexagonal polyhedron virus induced by the inoculation with tetragonal polyhedron virus. The degree of interference of primary hexagonal polyhedron virus by secondary tetragonal Ployhedron virus was increased as the dosage of secondary virus was increased. At the concentration of 1${\times}$10$\^$8/m1 of the secondary virus, the degree of interference was similar to. that of control group. On the other hand, infection with tetragonal polyhedron virus at low concentration was interfered by the primary virus. At the concentration of 1N10f/m1 of tetragonal polyhedron virus, however, the rate of infection with tetragonal polyhedron virus was increased sharply, which is still lower by 30 percent than that of control group. 5. In the studies of induction and virulence enhancement, based on the 1ate of mixed infection with hexagonal and tetragonal polyhedron viruses, the highest difference of infection rate between experimental group and control group exceeded 40 percent when the concentration of tetragonal polyhedron virus was 1${\times}$10$\^$7/m1. However, the infection rate of control group was not affected by concentrations of tetragonal polyhedron virus.

• Journal of Preventive Medicine and Public Health
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• v.20 no.1 s.21
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• pp.129-136
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• 1987

To determine the hepatitis 8 virus infection rate of the medical school students and appropriate time for immunization with hepatitis B vaccine,355 students in the 1st, 2nd and 3rd grades of Medical School of Kyungpook National University who had not been vaccinated and volunteered to participate in this study were tested for HBsAg, anti-HBs and anti-HBc with radioimmunoassay method (Abbott Lab. kit). A questionnaire was administered to ask the history of transfusion, acupuncture and surgery. HBsAg positive students were retested 16 months after the initial test. Overall HBsAg positive rate was 6.8% and the age adjusted rate for male (7.2%) was higher than that for female (4.9%). Anti-HBs positive rate was 35.3% (36.1% for male, 37.9% for female) and anti-HBc positive rate was 45.5% (46.5% for male,44.7% for female). Overall hepatitis B virus (HBV) infection rate was 49.1% and the infection rate for male (50.3%) was slightly higher than that for female (46.5%). HBsAg positive rate and infection rate were increased as the grade increased but it was attributed to the age distribution of the students. HBaAg positive rate for 20 years old students was 1.7%; 21 years, 6.6%; 22 years, 6.1%; 23 years, 12.2%; and 24 years and older, 6.4%. HBV infection rate showed an increasing trend as age increased; 45.8% for 20 years,41.5% for 21 years, 49.5% for 22 years, 55.5% for 23 years and 59.6% for 24 years and older. The age differences in HBsAg positive rates and HBV infection rates did not reach the statistical significance level of 0.05. However, these findings and similar age differences in HBsAg positive rates and HBV infection rates observed in other study suggest that there is a significant age differences. Study of the same age group in other schools and different social classes is warranted to confirm the age difference. Clarification of the reason for such differences would provide a clue to identify the major route of HBV transmission in this age group. Among 26 HBsAg positive students in the initial test, only one student was active hepatitis patient. Out of 24 students who had follow-up test after 16 months 22 students were positive for HBaAg and two students became HBsAg negative and anti-HBs positive. It is obvious that nearly one-half of the medical school students were infected with HBV before 20 years of age and the HBV infection occurs in medical school. Thus, it is recommended to test all the students for HBV infection soon after the admission to the medical school and immunize all the susceptible students with hepatitis B vaccine and give booster as they start to practice at a hospital.

• Korean Journal of Veterinary Service
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• v.24 no.2
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• pp.133-138
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• 2001

Cryposporidium species have a wide host range. These coccidian parasites are found in close association with epithelial cells of many species of animals including mm. The gastrointestinal tract is most commonly affected in young ruminants and this parasite is thought to be considerable importance in calf diarrhea complex. Major outbreaks of cryptosporidiosis have been reported in calves, lambs, pigs and others including avian species. Cryptosporidiosis is transmitted by oocysts of Cryptosporidium species. Because cryptosporidiosis is common infection among animals, early literature considered it a zoonosis. Human infections contracted from calves, cats, and horse feces. However, the resrvoir host is longer considered the major source of infection. Mild cases of disease have been reported in farm workers. Immunosuppressed, very young and very old persons should avoid contact with this parasite because it may cause severe diarrhea. In order to detect of Crytosporidium sp infection from feces of cattle and pigs at Chonbuk Iksan and Kunsan area, sedimentation and modified acid fast stain were applied. The positive rate of Cryptosporidium sp infection from 1, 176 of cattle and 267 of pigs were 0.5 % and 16.8%, respectively. According to area in Iksan and Kunsan, the positive rates were 0.4% and 0.9% from cattle, and 18.9% and 12.1% from pigs, respectively. In cattle, positive detection rate was 0.6% in milking cows but not in Korean cattle.

• Korean Journal of Health Education and Promotion
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• v.27 no.3
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• pp.49-57
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• 2010

Objectives: This study was conducted to investigate the occurrence and possible risk factors of enterobiasis among children in kindergartens. Methods: A total of 3,921 children were examined from 36 kindergartens in Ulsan, Korea. The parents were asked to complete questionnaires and to detect Enterobius vermicularis infection using the anal swab technique. Results: The overall rate of being positive for E. vermicularis egg was 7.8% ranged from 0 to 29.0%. The infection rate was related to age, gender, thumb sucking, pre-medication of anthelmintics, employment status of mother and number of siblings. The risk factors significantly associated with E. vermicularis infection were gender(OR 1.628), thumb sucking(OR 1.643), pre-medication of anthelmintics(OR 0.614), employment status of mother(OR 0.574) and number of siblings(OR 0.388). Conclusion: We propose that E. vermicularis infection screening among children in kindergartens should be continued on a regular basis. In addition, more intensive control program should be developed and applied to children.

• Research in Plant Disease
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• v.19 no.2
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• pp.114-117
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• 2013

To facilitate their spread, plant viruses have developed several methods for dispersal including insect and seed transmission. While insect transmission requires virus stability against insect digestion, seed-transmitted viruses have to overcome barriers to entry into embryos. Bean pod mottle virus (BPMV) is transmitted through seed at levels typically below 0.1%, but co-infection with Soybean mosaic virus (SMV) enhanced the seed transmission rate of BPMV in one experiment. In contrast, the rate of SMV seed transmission was not affected by BPMV co-infection. In a second preliminary study, the rate of SMV transmission was lower in an isoline of Williams 82 that contained a null mutation for the Kunitz trypsin inhibitor gene than in Williams 82. In this preliminary study, we observed that factors such as protease inhibitor expression and dual infection may affect the frequency of seed transmission of BPMV and SMV.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.19 no.2
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• pp.137-170
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• 2015

In this paper, we propose and analyze three viral infection models with humoral immunity including an eclipse stage of infected cells. The incidence rate of infection is represented by bilinear incidence and saturated incidence in the first and second models, respectively, while it is given by a more general function in the third one. The neutralization rate of viruses is giv0en by bilinear form in the first two models, while it is given by a general function in the third one. For each model, we have derived two threshold parameters, the basic infection reproduction number which determines whether or not a chronic-infection can be established without humoral immunity and the humoral immune response activation number which determines whether or not a chronic-infection can be established with humoral immunity. By constructing suitable Lyapunov functions we have proven the global asymptotic stability of all equilibria of the models. For the third model, we have established a set of conditions on the threshold parameters and on the general functions which are sufficient for the global stability of the equilibria of the model. We have performed some numerical simulations for the third model with specific forms of the incidence and neutralization rates and have shown that the numerical results are consistent with the theoretical results.

• Korean Journal of Veterinary Service
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• v.16 no.2
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• pp.91-96
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• 1993

In order to monitor the parasites, fecal samples were taken from turkey (n=157), helmeted guineafowl(n=149), pheasant(n=190) and duck(n=190) in Chonbuk province. The identification of the parasites were determined by the fecal examination using the fluatation method and microscopical examination. The results were obtained as follows；1. The detection rate oi the parasites from 4 species of poutry was 47.2%(n=324 heads) out of 686 heads. 2. The identification rate was 85.9% in helmeted guineafowl, 63.2% in pheasant, 44.6% in turkey and 3.2% in duck, in order. 3. The mixed infection rate such as single, double, triple and quadrupl was 25.4%(174 heads), 14.1%(97 heads), 7.3%(50 heads) and 0.4%(3 heads), respectively. 4. The parasites isolated were identified as Capillaria spp. in 225 heads, Eimeria spp in 169 heads, Heterakis gallinarum in 116 heads, Ascaridia galli in 16 heads, Hymenolepis spp. in 3 heads and Strongyloides avium in 1 head, in order.