• Pediatric Infection and Vaccine
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• v.25 no.3
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• pp.132-140
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• 2018

Purpose: The number of dengue fever cases is rising due to increasing overseas travel. Vaccination makes severe dengue fever in seronegative individuals after vaccination when they exposure to wild-type dengue virus. We investigated the seroepidemiology of the dengue virus for monitoring of Korean dengue virus immunity and establishing the prevention of dengue infection. Methods: The study was based on 446 residual sera collected from 98 infants (2 months to 1 year old), 152 adolescents (13 to 19 years old), 90 adults (20 to 50 years old), and 106 elderly participants (more than 65 years old) for other studies. Antibody levels for dengue virus immunoglobulin G (IgG) in each age group were measured using an enzyme-linked immunosorbent assay (ELISA). For each dengue virus IgG positive or equivocal result, an IgG ELISA was performed for Japanese encephalitis virus. Results: Of the 446 serum samples, only 1 (0.2%) adolescent had a positive result from the dengue IgG antibody test. In the dengue virus IgG antibody test, 14 (3.1%) samples showed equivocal results (10 adolescents and 4 elderly). In the 1 positive case of dengue virus IgG, the Japanese encephalitis IgG test was also positive. In the 14 equivocal cases of dengue virus IgG, there were 6 positive, 3 equivocal, and 5 negative of Japanese encephalitis IgG. Conclusions: The seroprevalence rate of dengue virus was very low in Koreans. This study provides important data for establishing the policy for preventive measures of dengue fever. It will be necessary to continuously monitor for dengue virus immunity.

• Parasites, Hosts and Diseases
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• v.55 no.6
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• pp.607-611
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• 2017

Primary maternal infection with toxoplasmosis during pregnancy is frequently associated with transplacental transmission of the parasite to the fetus. This study was conducted to test the utility of PCR assay to detect recent infections with Toxoplasma in aborted women at various gestational ages who referred to Obstetrics and Gynecology Department of Alavi Hospital in Ardabil during 2014 and 2016. Two hundred women with a history of single or repeated abortion were investigated in this study. Blood samples were tested for specific anti-Toxoplasma IgM and IgG antibodies by ELISA. According to the results, 53.5% of the women under study were positive for anti-Toxoplasma antibodies: 4.0% of them had IgM, 43.0% had IgG, and 6.5% had both IgM and IgG. Subsequently, Nested-PCR analysis was used to detect T. gondii DNA in the placenta of subjects. In 10.5% of the women, the results were positive for 529 bp element of T. gondii. Among them, 5 (23.8%) cases were IgM positive, 1 (4.8%) case was IgG positive, and 11 (52.4%) were both IgM and IgG positive. In 4 (19.0%) patients, none of the antibodies were found to be positive. In total, 16 patients had positive results in both ELISA and PCR methods, and 174 cases had negative results for new infection. The findings of this study revealed that T. gondii might be one of the significant factors leading to abortion, and that the analysis of placenta can be important in order to achieve increased detection sensitivity.

• Parasites, Hosts and Diseases
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• v.47 no.3
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• pp.219-225
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• 2009

The seroprevalence of cryptosporidiosis was examined using patients' sera collected from hospitals located in 4 different areas of the Republic of Korea. ELISA was used to measure antibody titers against Cryptosporidium parvum antigens from a total of 2,394 serum samples, which were collected randomly from patients in local hospitals; 1)Chungbuk National University Hospital, 2) Konkuk University Hospital, 3) local hospitals in Chuncheon, Gangwon-do (province), 4) Jeonnam National University Hospital, from 2002 through 2003. Of the2,394 samples assayed, 34%, 26%, and 56% were positive for C. parvum-specific IgG, IgM, and IgA antibodies, respectively, Positive IgG titers were most common in sera from Jeonnam National University Hospital, Gwangju, Jeollanam-do, and positive IgM titers were most common in sera from Chungbuk National University Hospital, Cheongju, Chuncheonqbuk-do. The seropositivity was positively correlated with age for both the IgG and IgA antibodies but was negatively correlated with age for the IgM antibodies. Western blotting revealed that 92%, 83%, and 77% of sera positive for IgG, IgM, and IgA ELISA reacted with 27-kDa antigens, respectively. These results suggested that infection with Cryptosporidium in hospital patients occurs more commonly than previously reported in the Republic of Korea.

• The Journal of Korean Society of Virology
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• v.30 no.1
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• pp.11-18
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• 2000

Since $Hantavax^{TM}$, formalin inactivated Hantaan virus vaccine (10,240 ELISA units/ml), has been developed in 1990 to prevent against haemorrhagic fever with renal syndrome (HFRS) caused by Hantaan or Seoul virus, it has been commercially available in Korea. Twenty-one healthy people were booster shot once and twice after primary basic vaccination with $Hantavax^{TM}$. Seroconversion rates were measured by immunofluorescent antibody technique (IFAT), enzyme-linked immunosorbent assay (ELISA), high density composite particle agglutination (HDPA), and plaque reduction neutralization test (PRNT). Seroconversion rates of 21 vaccinees at one year after primary basic vaccination were 52.3%, 95.2%, 0.0%, 47.6%, and 28.6%, and 13 vaccinees at one month after 1st booster vaccination were 100%, 100%, 30.7%, 100% and 100% by IFAT, ELISA (IgG, IgM), HDPA and PRNT, respectively. Seroconversion rates declined slightly by twenty months, and they were 84.6%, 92.3%, 0.0%, 84.6% and 69.2% by IFAT, ELISA (IgG, IgM), HDPA and PRNT, respectively. Seroconversion rates of 9 vaccinees at three months after 2nd booster vaccination were 100%, 100%, 0.0%, 100%, and 88.9%, and 16 vaccinees at one year after the 2nd booster vaccination were 87.5%, 93.8%, 0.0%, 87.5% and 81.3% by IFAT, ELISA (IgG, IgM), HDPA and PRNT, respectively. Based on the above result $Hantavax^{TM}$ has proved a vigorous anamnestic response after the 1st and the 2nd booster vaccination and has persisted higher fluorescence, agglutination and neutralizing antibody titers in vaccinees.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.15 no.2
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• pp.85-90
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• 2012

Purpose: Commercial enzyme-linked immunosorbent assay (ELISA) kits have been considered less reliable for children than for adults. The aim of this study was to compare four ELISA kits and in-house immunoblotting based on the analysis of anti-H. pylori-IgG antibody reactivity. Methods: A total of 399 serum samples were collected at the GNU Hospital during 1998-1999. All sera were tested using ELISA and immunoblotting. Statistically significant differences were determined by the $x^2$ test. Results: The overall seropositivity rates using GAP IgG, Genedia IgG, HM-CAP, Pyloriset EIA-G, and immunoblotting were 13.0%, 25.1%, 18.3%, 15.8%, and 62.9%, respectively. Immunoblotting showed a higher seropositivity rate than did all four ELISA kits in all age groups. Genedia IgG had the highest seropositivity among the ELISA kits. The seropositivity rate for children aged 13 to 18 months was lowest, and that of children aged 15 years was highest (90.0%). The seropositivity rate for children aged 7 months to 5 years was significantly lower than that for children aged 6 to 15 years among the four ELISA kits (p<0.0001) and immunoblotting (p=0.02). Conclusion: Immunoblotting is the most sensitive test for detection of anti-Helicobacter pylori IgG antibodies among the serological tests in this study. These results emphasize the need for standardization when commercial ELISA tests are used in different nations or in young age groups. Immunoblotting could be a suitable noninvasive assay for serodiagnosis and seroepidemiologic study of H. pylori infection in Korean children.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.1
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• pp.281-283
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• 2016

The Cholangiocarcinoma is a. The risk of development of cholangiocarcinoma, generally a rare type of a liver tumor, increases during infection of Opisthorchiasis. For this reason the timely detection of Opisthorchiasis is important for Cholangiocarcinoma prevention. There are many studies which concern the detection of pathogenesis of Opisthorchis viverrini infection but a little known about Opisthorchis felineus. In this study we investigate a correlation of the eggs which are found in a faeces and are comparable with a serum Ig G and Ig M antibody level that were detected with ELISA test in a large group of patients. The result is showing positive correlation between evidence of the Opisthorchis felineus eggs that were found in a faeces and antibody Ig G and Ig M level in a serum. Moreover the combination of two methods can improve the Opisthorchiasis diagnostic: the serum antibody and faeces investigation of eggs.

• Parasites, Hosts and Diseases
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• v.59 no.6
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• pp.565-572
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• 2021

Toxoplasma gondii ME49 infections are typically diagnosed by serological tests. However, serological diagnosis of RH strain-induced toxoplasmosis remains unknown. In order to develop seradiagnosis of above 2 kinds of infections, we generated recombinant virus-like particles (VLPs) displaying the T. gondii rhoptry protein 4 (ROP4) and evaluated their potential in T. gondii ME49 or RH strain infection diagnostics. Mice were orally infected with either the tachyzoites of T. gondii (RH) or cysts of T. gondii (ME49) at various dosages, and sera were collected at regular intervals. ELISA-based serological tests were performed to assess IgG, IgM, and IgA antibody responses against ROP4 VLP antigen and tissue lysate antigen (TLA). Compared to TLA, IgG, IgM, and IgA levels to ROP4 VLP antigen were significantly higher in the sera of T. gondii RH-infected mice 1 and 2 week post-infection (PI). T. gondii-specific IgG antibody was detected at 1, 2, 4, and 8 week PI in the T. gondii ME49-infected mice with infection dose-dependent manner. These results indicated that the ROP4 VLP antigen was highly sensitive antigens detecting T. gondii RH and ME49 antibodies at an early stage.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.387-391
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• 1986

Serum samples from 51 patients with clinically suspected typhoid fever were tested for immunoglobulin G (IgG), IgM and IgA antibodies against the whole bacteria antigen of Salmonella typhi by an enzyme-linked immunosorbent assay. The levels of IgG and IgA antibody to-whole bacteria antigen were higher in the culture-proven patients than in controls. The levels of IgM antibody to- whole bacteria antigen showed better discrimination between culture negative patients and controls than those of IgG or IgA antibody to-whole bacteria antigen. The enzyme-linked immunosorbent assay was much more sensitive than the Widal test. It would be a useful tool for the diagnosis of typhoid fever with a single serum sample.

• Biomedical Science Letters
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• v.5 no.2
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• pp.147-153
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• 1999

The changes of antibody titer were observed in rats which were experimentally infected with Echinostoma hortense metacercaria. Serum levels of IgG and IgM were measured by enzyme-linked immunosorbent assay (ELISA). The mean absorbance values obtained for specific-IgG were from 0.130$\pm$0.014 (mean$\pm$S.D.) to 0.480$\pm$0.073. The peak appeared in the 4th week after infection, then declined slowly during the 5th and 6th week, although mild elevation apperared in the 8th week. The mean absorbance values of specific-IgM were detected from 0.160$\pm$0.034 to 0.409$\pm$0.084. The peak value (0.409$\pm$0.084) was on the 14th day after infection, then declined on the 8th week. Results showed that the assay could be used for detection of E. hortense infection in experimentally infected rats or laboratory experiments where evidence of infection is required.

• The Journal of the Korean Society for Microbiology
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• v.21 no.2
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• pp.205-210
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• 1986

Serological investigations for the leptospirosis on hospitalized patients in Choonchun Sungsim Hospital during the periods from August to November 1985 and 841 inhabitants of Kangwondo area including Choonchun, Choonsung, Inje, Chulwon, Hwachun, Gosung, Taibaik, Samchuk and Yangju area were carried out. 1. Among 58 hospitalized patients who were suspected as leptospirosis, 10 patients were detected to have antibody against Leptospira. All of positive sera had the highest antibody titer against serogroup Icterohemorrhagiae and most positive sera were also reactive to serogroup Australis and Canicola. Antibody titer of positive sera detected by microscopic agglutination(MA) test were ranging from 1 : 40 to 1 : 2,560. Antibody titer detected by ELISA method were higher than those detected by MAT(ELISA 1 : 400$\sim$1 : 25,600) and IgM titer of positive sera were generally higher than IgG titer. 2, Of 841 inhabitants in 8 area of Kangwondo, 17 persons (2,02%) possessing antibody against Leptospira were detected by ELISA method, IgG titer in positive sera were generally higher than IgM titer. Persons possessing antibody to Leptospira were distributed in both sex and in various age group, and no significant regional and occupational fluctuations were obserbed.