• 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.

• The Journal of the Korean Society for Microbiology
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• v.1 no.1
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• pp.3-3
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• 1958

• Journal of Preventive Medicine and Public Health
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• v.20 no.1 s.21
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• pp.137-146
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• 1987

The following facts have been identified as a result of epidemiological trend and characteristic of Japanese Encephalitis in Korea for the last 20 years. First: The Epidemiological period which was ten-year and three-year in the past has been disappeared following the start of immunization program at 1970. Second: The Incidence rate was much higher in the south and West areas than northeast area of Korea. City and Province with the highest incidence rate was Chungcheong Nam Province and Cholla Buk Province. Third: Regardless of scope of prevalence, the main season that 90 percent of total incidence occurrs in one month from mid-August through mid-September. Fourth: The number of case by age was that 80 percent of total patients is children aged $3{\sim}15$. Recently there is an increase in the number of patients who are elderly people. Fifth: The study on the ecological conditions of mosquito including wintering and effectiveness of immunization for Japanese Encephalitis and duration on antibody should be done. Sixth: There has been no case of Japanese Encephalitis for the last three years since 1984 mainly due to disinfecting to eradicate mosquitos, immunization for vulnerable group of people aged $3{\sim}15$, individual precaution not to be bitten by mosquito, improvement of environment sanitation. While there has been no case of Japanese Encephalitis during last three years, there is possibility that Japanese Encephalitis becomes prevalent again anytime since its virus has been isolated continuously from the natural reservoirs.

• Korean Journal of Veterinary Research
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• v.10 no.2
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• pp.59-66
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• 1970

Studies were conducted on the survey of HI antibody abortion and stillbirth from J.E. virus in swine for 1968-1969 in Korea HI antibody against J.E. virus showed postive in June or July and reached 80~100 percent of postive in August or September and J.E. virus strains were isolated from the brain material of the aborted piglets.

• The Journal of Korean Society of Virology
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• v.26 no.2
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• pp.191-204
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• 1996

The characterization of the 5 Korean isolates (K96P10, K94P05, K91P55, K87P39, and K82P01) of Japanese encephalitis virus (JEV) was compared with JE virus prototype Nakayama-NIH (NKY-NIH) using prM/M and envelope gene sequences of the JEV genome and phylogenetic analysis. The antigenic analysis of these viruses were done by the cross-hamagglutination inhibition (HI) test using polyclonal antibodies against Korean isolates and NKY-NIH. The sequence homology of the Korean isolates and NKY-NIH ranged between 87.4 % - 95.6 % at the nucleotide level and between 98.2 % - 97.2 % at the amino acid level over the E nucleotides compared. Alignment of E protein amino acid sequences revealed that residue positions E89, E129, E221, E244, E327, E366, E459, and E477 characterized the Korean strains. According to phylogenetic analysis bases on the E nucleotide, there are at least 2 genetic types of JEV existing in Korea and Korean strains were distinct from NKY-NIH. However, the cross HI test results of all the Korean isolates were serologically no different from NKY-NIH strain.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1580-1587
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• 2012

Japanese encephalitis virus (JEV) envelope (E) protein holds great promise for use in the development of a recombinant vaccine. Purified recombinant E (rE) protein may be useful for numerous clinical applications; however, there are limitations in using the Escherichia coli expression system for producing high-quality rE protein. Therefore, in this study, the yeast expression system was used to generate the rE protein. For protein production using the yeast system, the full-length JEV E gene was cloned into Pichia pastoris. SDS-PAGE and immunoblotting analysis demonstrated that the rE protein had a molecular mass of 58 kDa and was glycosylated. The predicted size of the mature unmodified E protein is 53 kDa, suggesting that post-translational modifications resulted in the higher molecular mass. The rE protein was purified to greater than 95% purity using combined ammonium sulfate precipitation and a SP-Sepharose Fast Flow column. This purified rE protein was evaluated for immunogenicity and protective efficacy in mice. The survival rates of mice immunized with the rE protein were significantly increased over that of Hyphantria cunea nuclear polyhedrosis virus E protein (HcE). Our results indicate that the rE protein expressed in the P. pastoris expression system holds great promise for use in the development of a subunit vaccine against JEV.

• Korean Journal of Veterinary Research
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• v.57 no.1
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• pp.31-36
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• 2017

Japanese encephalitis (JE) is an important zoonosis caused by the mosquito-transmitted JE virus (JEV), which is a causative agent of reproductive failure in pregnant sows. Detection of JEV antibodies in swine is performed by hemagglutination inhibition (HI), virus neutralization (VN), and the plaque reduction neutralization test (PRNT). The most stringent PRNT is the 90% endpoint PRNT ($PRNT_{90}$). These conventional assays are difficult to carry out in diagnostic laboratories with insufficient instruments or cell culture systems. An alternative assay that is easily conducted and time efficient is required. In this study, we improved the indirect enzyme-linked immunosorbent assay (I-ELISA) with clarified antigen for the detection of JEV antibodies. The I-ELISA results obtained from 175 swine serum samples were compared with HI, VN, and $PRNT_{90}$ results. The sensitivity of I-ELISA was 91.8%, 95.0%, and 94.7% compared with HI, VN, and $PRNT_{90}$ results, respectively. The specificity of I-ELISA was 92.2%, 94.7%, and 94.7% compared with HI, VN, and $PRNT_{90}$ results, respectively. Moreover, the I-ELISA results were significantly correlated with the HI (r = 0.93), VN (r = 0.95), and $PRNT_{90}$ (r = 0.92) results. These results suggest that the improved I-ELISA is useful for serosurveillance of JEV in swine.

• Korean Journal of Microbiology
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• v.30 no.2
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• pp.115-123
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• 1992

A total of453 wilci hats inhabiting in Korea were captured ancl .he IgG antibodies againstJapanese Encephalitis Virus(J1IV) were detected by the heniagglut:nation inhibition te5t. 35501' the 453 blood sera showecl positive reaction to JEV with titers of I0 up to 40. Positiverates of male and kniale hats were 70.0'%1 anel 78.1'k. rcspectivclv. Positive ratci accordingto area were 74.7%) in Chungnan~. 72.h'\ulcorner6 in Kangwon and 74.3'"; in C'hungbuk. the resultbof which indicated no dil'krencc in areii. Whereas positive ratus according to hats specie5were 87.5(% f i ~ rC i..cpc~rtilios upernns. fi~llowedb y 83 3'%, k)r Mpoii.\ i ~ ~ : t r u ~ i tci.i~lis~. ~75l.0. '\4 1 forRhitrolol~h.\ '||'&'||',rurn~uic,r~unal ncl 59.6'!41 for Minioprc,ru.s schrc~ibersii.I t was Ibund by incli rrctini~nunofluorosce~icae nd clectron microscope techniques that the virus particles 01. JEVcould infect the brain of a Korean wilcl bats and proliferatn ill the brain cells.he brain cells.

• KSBB Journal
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• v.13 no.3
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• pp.231-237
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• 1998

An attenuated Japanese encephalitis virus (JEV) clone SA-14-14-2(Vero) was obtained through successive adaptation of a primary cell adapted strain, SA-14-14-2(PDK) to Vero cell, a continuous line of monkey kidney cells. The virus titer reached above the 107 plaque forming unit (pfu) per mL of culture supernatant with 3 passages in Vero cells and was maintained close to this level in the further passages. The optimum temperature for the virus growth was $35^{\circ}C$. Growth pattern of the virus indicated that optimum time for the virus harvest is 4 days post infection and the virus accomplished rapid initial propagation even in medium containing no serum supplement. The roller bottle (RB) system and the spinner flask (SF) system using micro-carrier (Cytodex-1) for the JEV cultivation were explored. When RB, SF, and T-flask culture system were compared, there was no significant difference in virus yield. Furthermore, the results indicated that virus could be harvested multiple times from 3 days to 9 days post infection; neither severe cytopathic effect (CPE) in the infected cells nor the decrease in the titer was observed on duration of 9 days.

• The Journal of the Korean Society for Microbiology
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• v.3 no.1
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• pp.43-49
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• 1968

Japanese encephalitis(JE) shows its explosive epidemicity in the temperate zone of Asia but little is known on the overwintering mechanism. One of the hypotheses on the overwintering mechanism is that the virus overwinters in the hibernating animals. There has been no report on the proliferation of JE virus(JEV) or antibody formation in the snakes. The purpose of this experiment is to explore the mutual relationship between JEV and snake and to clarify whether JEV proliferates and induce antibody formation in snakes. Three species of non-poisonous common snakes were employed. Precipitation test was carried out after injecting calf serum and, HI and neutralization tests were done by injecting JEV into the snakes. The gamma globulin fraction of pre- and post-injection serum were compared by paper chromatography. According to the results, precipitating antibody reaction to calf serum could be observed only at $4^{\circ}C$. It was failed to demonstrate HI antibody formation but neutralizing antibody could be detected in one of the 9 snakes. Although antibody could not be detected in test-tube, tile result of paper chromatography shows the remarkable increase of gamma globulin fraction after the injection. Above results are strongly indicating the antibody formation in the snakes.