• Journal of Preventive Medicine and Public Health
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• v.40 no.4
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• pp.285-290
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• 2007

Objectives : Cases of human brucellosis in Korea have recently increased due to the increasing incidence of bovine brucellosis. The authors conducted this study to elucidate the status of brucellosis through seroepidemiologic study. Methods : We selected our study population from a high risk group. We conducted a questionnaire survey and obtained blood samples to determine the seroprevalence of brucellosis antibodies for 10 days in February, 2005. The titers of brucellosis were measured by the combination of standard tube agglutination test (STA) and enzyme-linked immunosorbent assay (ELISA) test. Results : Our study subjects comprised 1,075 cases: 971 livestock workers, 51 veterinarians, and 53 artificial inseminators. In the STA test, 27 cases (2.5%) had titers of greater than or equal to 1:20. Of 1,068 cases (7 cases were excluded due to previous brucellosis), 7 cases of brucellosis were diagnosed with titers of 1:160, giving a seroprevalence of brucellosis of 0.66%. The seroprevalence in the male group was 0.95%, and that of livestock workers, veterinarians, and artificial inseminators was 0.52%, 4.17%, and 0.00%, respectively. The Spearman's correlation coefficient between the positive rate of bovine brucellosis per capita and household and human brucellosis was 0.806 and 0.744, respectively. The concordance rate between the Korea National Institute of Health and the Gyeongsangbuk-do Institute of Health and Environment by the STA and ELISA tests was 94.7% and 100.0%, respectively. Conclusions : The study results indicated in higher seroprevalence rate among veterinarians than among livestock workers and artificial inseminators. Because veterinarians may be exposed to this high risk, effective working guidelines for veterinarians to guard against brucellosis must be developed. Moreover, more extensive epidemiologic research for laboratory workers and meat handlers is needed.

• Journal of Preventive Medicine and Public Health
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• v.54 no.5
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• pp.370-375
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• 2021

Objectives: The number of cases of hepatitis A virus (HAV) infections has sharply increased in Korea, especially among young adults. In this study, an HAV outbreak in a facility for disabled people was investigated, and we found epidemiological differences both between 2 different generations and between generally abled and disabled groups. Methods: We analyzed the incubation period and attack rate of an HAV outbreak and investigated the prevalence of HAV antibodies among the staff and residents of a facility for the disabled. We performed a retrospective cohort study during the HAV outbreak, which lasted from February 8 to 25, 2019, including examinations of HAV antibody tests and post-exposure HAV vaccination for the staff or residents of the facility. Results: There were 9 confirmed cases in 2 staff members and 7 residents. Among 53 people (30 staff and 23 residents), except for the 9 confirmed cases and 1 staff member with a known history of HAV infection, HAV seroprevalence was seen in 16.7% of the staff under 40 years of age and 95.2% of those over 40 years of age, while the corresponding rates in the residents were 0.0% and 58.8%, respectively. Conclusions: This result implies that it is necessary to prioritize HAV vaccination for vulnerable groups and workers of residential care facilities.

• The Journal of the Korean Society for Microbiology
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• v.17 no.1
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• pp.7-14
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• 1982

A model of induction of neoplasia by viruses has develpoed from experimental studies in animals and in cultured cells and oncogenic transformation of cells is the result of integration of viral genetic information into the cellular DNA. The evidence for these associations was derived primarily from seroepidemiologic investigation. However, data indicating that the relation between HSV-2 and cervical cancer fits the model derived from experimental animal studies are not yet sufficient to draw conclusion with regard to the etiologic role the virus in the development of the neoplasms. In other hand, the K562 tumor cell is highly susceptible target for natural killer cell lysis by the lymphocytes of human and murine periperal blood. The characteristics of this effector cell type has been investigated. A study on natural killer cell mediated cytotoxicity(NKMC) against $^{51}Cr$-K562 as target cell was studed in HSV-2 infected ICR mouse. We have studied for susceptibility of HSV-2 against mouse embryo fibroblast(MEF) cells and NKMC from HSV-2 infected mouse. The results obtained that the mouse embryo fibroblast cells culture, the number and size of the cells were markedly increased and formed a monolayers relatively rapid, and become complete monolayer sheet around 72 hrs. Duration of cytopathic effect on MEF cells was rapid by serial passing of HSV-2. The morphology of the HSV-2 infected cells appear to be mainly round, ovium, spindle form and some of them was forming large giant cells. The NKMC was decrease in mouse with HSV-2 and comparison between effector/target cells ratio as 25:1 and 50:1 respectively, the NKMC was found to be more significantly decreased than normal control we have concluded that the natural killer cell activity of the viral infected mouse was shown as a suppressed during the HSV-2 infection, day 7th and 14th.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.233-238
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• 1996

The seroepidemiologic studies on antral-ToxopIasma antibody titers were carried out using ELISA and indirect latex agglutination test. Among 899 sera prepared from pregnant women, 39 cases (4.3%) revealed positive reaction and 218 sera from middle school students showed 4 positive reaction (1.8%) by ELISA. By LAT (newly established by National Veterinary Research Institute, Korea), the sera of 7 pregnant women (0.8%) showed positive reaction. When 80 sera showing ≥ 1 :8 by LAT were used for comparing the results obtained from LAT and Toxotest-MT (Eikon Chemical Co., Japans, 7 cases and 8 sera were positive, respectively. All of 11 sera of proven toxoplasmosis patients showed positive reaction in both tests. Overall proportion of agreement between LAT kit and Toxotest-MT was 0.94 (K-index : 0.632, p < 0.01), and LAT was considered to be useful for the screening of toxoplasmosis.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.2
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• pp.134-145
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• 2010

Purpose: The serologic diagnosis of rotaviral infections is not commonly used in clinical practice, but is used in seroepidemiologic studies. In this study, the usefulness of Escherichia coli-expressed recombinant VP6 proteins of group A rotavirus in the serodiagnosis of rotavirus infections by ELISA was evaluated. Methods: The recombinant VP6 proteins of group A rotavirus expressed in E. coli Rosetta II strain were purified and identified. One hundred sera from 22 children (4 healthy neonates, 13 healthy children, and 5 immunocompromised children) who had serial sera samples prior to and after rotavirus infections were provided by the Gyeongsang National University Hospital, a member of the National Biobank of Korea. IgG, IgA, and IgM antibodies against rVP6 were analyzed by ELISA in all of the patients and Western blot analysis in 4 neonates. Results: ELISA tests using rVP6 proteins of group A rotavirus as antigen revealed that IgG, IgA, and IgM antibodies increased after rotaviral infections in most neonates and healthy children. IgG antibodies also increased after rotaviral infections in most immunocompromised children without an adequate increase in IgM or IgA antibodies. Western blot analysis in four neonates revealed very early IgM antibody responses, even in the sera with low optical densities in ELISA tests. Conclusion: Our study showed that ELISA using rVP6 as an antigen is a valid diagnostic tool for seroepidemiologic studies of rotavirus infections and Western blot analysis is a sensitive test in detecting IgG, IgA, and and IgM antibodies in patients with rotavirus infections.

• The Journal of Korean Society of Virology
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• v.27 no.2
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• pp.161-168
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• 1997

The present study was designed to estimate the seroprevalence of NLVs among diarrheagenic children and in healthy adults in Seoul and its vicinity with the use of an EIA and an Western blot (WB) based on recombinant Norwalk virus capsid protein (rNV) and crude virus preparations as antigen. Seroconversion was observed in 34 (83%) of 41 tested using the EIA and in 21 (54%) of 39 using the WB, suggesting that the NLVs with epitopes common to rNV are prevalent in Seoul area. Diarrheal children who were known to have been infected with several other strains of the NLVs showed no significant antibody response to the rNV. Infection with rNV occurred earlier in life: primary infections with rNV were common before the age of 6 months and over 91 % of children had evidence of infection by that age by the EIA. Since the amount of the NLV antigens available for seroepidemiologic surveys is limited, we tried to detect NLV antibody by using crude virus preparations as antigen. One crude virus preparation of a child whose stool yielded genetically distinct NLV revealed the presence of the plural number of bands upon SDS-PAGE, but precipitated only one band (62 kDa) after the WB with a serum (collected 10 days after the onset of symptoms) of another diarrheal child. The WB assay we present in this report revealed that the NLVs are prevalent among Korean population and that the sera contained antibody to a single major structural protein, with molecular sizes of 58 to 62 kDa, compatible with the sizes reported for the Norwalk virus and Snow Mountain agent proteins, respectively. When the results of the WB were compared with those obtained by the EIA, the EIA antibody assay was sensitive enough to detect an antibody rise of as much as 4096-fold but not as specific as the WB. The WB assay presented in this paper will provide a powerful tool to elucidate not only antigenic structures of the NL Vs but also seroepidemiology of the NLV infection. The availability of an unlimited source of antigen will enable a large scale serologic studies that will greatly increase our understanding of the role of NLVs in human enteric illness.

• Journal of Preventive Medicine and Public Health
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• v.35 no.2
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• pp.129-135
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• 2002

Objective : The primary objective of this study was to estimate the prevalence of HBsAg-positives in the late 1990's among Korean adults. In addition, we evaluated the association of age, a residential area, a vaccination rate, a family history of chronic liver diseases and a past history of acute liver disease with the seropositivity of HBsAg, and estimated the prevalence of chronic HBV infection by follow-up for 6 month or more. Methods : A total of 10 areas, six metropolitan and four small cities, were selected. In each cities, one health screening center was selected for recruitment of study subjects. The study subjects were enrolled from a general health examination program that is provided by medical insurance companies. Questionnaires on various risk factors were administered to the study subjects. Sera was drawn and tested for HBsAg by radioimmunoassay. HBeAg and ALT were also tested for those of HBsAg positive. The HBsAg positives was retest for HBsAg 6 months later Results : Among the study subjects (n= 1816), the seroprevalence of HBsAg was 5.5% (95% CI=4.5%-6.6%), 7.4% in men (95% CI=5.8-9.4) and 3.6% in women (95% CI=2.5-5.0). A past history of acute liver disease and a family history of chronic liver diseases was shown to be risk factors for HBsAg positivity. Among the 31 HBsAg-positives, negative seroconversion rate was estimated to be 3.2%, Thus, prevalence of chronic HBV infection was estimated to be 5.3% (95% CI=3.7-6.6). Conclusion : In this study, the HBsAg seroprevalence rate was lower than that of the other studies in 1980's, particularly in young adult and women. Considering the public health importance of liver cancer and chronic liver diseases, the further effort is needed to prevent and reduce the HBV infection.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.232-239
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• 1997

Purpose: The incidence of hepatitis A virus(HAV) infection has markedly decreased in the last 20 years due to industrialization and improvements in the standard of living and hygiene in Korea. The reduction in seroprevalence rates indicates infection potential for young adult population, and a need for vaccinations in high-risk adults and children groups has been suggested. In this study we evaluated the seroprevalence rates and natural infection rates of hepatitis A in children and adolescent to obtain the basic data for vaccination of hepatitis A. Methods: A total of 334 children and adolescent subjects below 20 years old in Kyonggi-do province were examined for HAV antibody and seroprevalence rates in each age group was investigated. In 584 elementary school students residing in Kyonggi-do province, serum samples collected in 1993 and 1996 from the same subjects for investigation of natural seroconversion rates. Method of testing antibody was enzyme immunoassay. Results: 1) The seropositive rate of HAV in 334 subjects aged below 20 years old was 5.4%. According to age, the seropositive rates were 27.3% in infant group, 0.0% in 1~4 year-old group, 0.0% in 5~9 year-old group, 2.9% in 10~14 year-old group and 15.0% in 15~19 year-old group. 2) In the study of 584 elementary school children, only one subject showed seropositive in 1993, and in 1996 three different subjects showed seropositive results(0.5%); the natural seroconversion rate during 3 years was 0.5%. 3) The seroprevalence rates of below 20 year-old subjects reported in previous studies were 63.8% in 1979 and 47.3% in 1989 while the present study showed the rate at 5.4%. Conclusion: Since natural antibody formation is rarely occurring, there is a high risk for apparent hepatitis A infection in adults. Therefore vaccination in high risk groups is essential at present, and in order to reduce the chance for hepatitis A infection in adults, vaccination in children may be needed.