• Korean Journal of Microbiology
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• v.35 no.1
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• pp.82-88
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• 1999

In this study, to evaluate newly developed Japanese encephalitis (JE) vaccine candidate CJ50003, we assessed its immunogenicity along with a previously commercialized inactivated JE Biken vaccine. The CR0003 viral antigens produced in Vero cells were administered suhcutaneouly to mice either with alum-adjuvanled or free form. The ELISA titers and neutralizing (NEUV antibody titers accounting for major protective immunity in JE were determined. Mice given alum-adjuvanted vaccine had a 10 times higher antigen-specific NEUT antibody response than did those which {lad received free antigens. This NEUT antibody response was maintained until day 168 with NEUT titer more than 1:160. Even with the 0.5 ng of alum-adjuvanted antigen dose, NEUT titer was induced more than 1:10 which is considered as an evidence for seroconversion and protection. Thc mice immune sera had a similar rate of cross-reactivity against three different viral antigens, Nakayama-NlH, P3 and SA14; as determined by ELISA assay. In a mice challenge model, vaccination with the GI50003 conferred more protection than with commercialized Biken vaccine against Nakayama virus. These data demonstrated that CJ50003 vaccine candidate has an excellent prophylactic efficacy and implicated it has a strong potential for further development and commercialization.

• Parasites, Hosts and Diseases
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• v.29 no.1
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• pp.67-86
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• 1991

In order to determine the seasonal prevalence and population dynamics of Culex tritaeniorhynchus in relation to the epidemics of Japanese encephalitis, and ecology of these vector mosquito in Kyungpook Province, Korea, studies were con- ducted during the Period of 7 years from 1984 to 1990. Cx. tritaeniorhynchus first collected in June between 4th and 28th, and trapped in large numbers during the period from mid-August to early September, showed a simple sharply pointed one-peaked curve. There was a gradual decrease from mid-September, with a very small number of them collected until early October in every year. The average number of Cx. tritaeniorhynchus rapidly decreased after 1985, and the number became particularly low in 1989. The highest population density, which was observed in August during the initial three years, was found to be delayed in the following years, accompanied by a decrease in the number of mosquitoes. In the trend of nocturnal activity of Cx. tritaeniorhynchus, with oncoming darkness they become very active, gradually decreasing in activity toward mid night, but slightly increasing toward dawn. The immature stages of Cx. tritaeniorhynchus were first found in rice fields contributing to peak adult densities in mid-July. The highest average densities of Cx. trisaeniorhynchus was 14,900 per m2 on mid-August 19th. The larval Cx. tritaeniorhynchus showed high resistance levels and resistance ratios against 5 organophosphorus compounds. In the adult horisontal life table characteristics of Kyungsan colonies of Cx. tritaeniorhynchus under insectary condi- tions, life expectancy was 28.3 days for males and 59.8 days for females. The net reproductive rate was 7.8 and generation time was 25.6 days.

• 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.

• 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.

• Korean Journal of Veterinary Service
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• v.27 no.3
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• pp.281-288
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• 2004

As all other intensively farmed domestic species, most mortality in ostriches is closely to rearing conditions. While ostriches is also highly sensitive to stress, species-specific infectious disease play only a minor role. But investigation of ostrich's disease is not peformed almost in Korea. The study was performed to investigate the titers of antibody for Newcastle disease(ND), Infectious bronchitis(IB), Egg drop syndrome '76(EDS), Avian influenza(AI), salmonellosis, Mycoplasma gallisepticum infection(MG), Mycoplasma synoviae infection(MS), Infectious bursal disease(IBD), Brucellosis, Toxoplasmosis, Japanese encephalitis(JE), Porcine parvovirus infection, Encephalomyocarditis and Porcine reproductive respiratory syndrome (PRRS). The results obtained in the 62 ostrich sera slaughtered in Gyeongbuk province were summarized as follows: The average of antibody positive rates to ND, IB, EDS, AI(H9Nl), JE, Porcine parvovirus infection and Encephalomyocarditis by HI test were $75.8\%,\;100\%,\;0\%,\;0\%,\;51.6\%,\;50\%\;and\;56.5\%$ respectively. The antibody positive rates to salmonellosis, MG, MS by plate agglutination test were $12.9\%,\;25.8\%,\;and\;0\%$ respectively. Antibodies to disease agent such as IBD and AI by agar gel precipitation(AGP) test, Brucellosis by tube agglutination, toxoplasmosis by latex agglutination test and PRRS by IFA were all negative.

• Proceedings of the Microbiological Society of Korea Conference
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• 2003.05a
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• pp.83-86
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• 2003

Major advances in positive-sense RNA virus research have been facilitated by the development of reverse genetics systems. These systems consist of an infectious cDNA clone that encompasses the genome of the virus in question. This clone is then used as a template for the subsequent synthesis of infectious RNA for the generation of synthetic viruses. However, the construction of infectious cDNA for the Japanese encephalitis virus (JEV) has been repeatedly thwarted by the instability of its cDNA. As JEV is an important human pathogen that causes permanent neuropsychiatric sequelae and even fatal disease, a reliable reverse genetics system for this virus is highly desirable. The availability of this tool would greatly and the development of effective vaccines as well as facilitate studies into the basic biology of the virus, including the molecular mechanisms of viral replication, neurovirulence, and pathogenesis. We have successfully constructed a genetically stable infectious JEV cDNA containing full-length viral RNA genome. Synthetic RNA transcripts generated in vitro from the cDNA were highly infectious upon transfection into susceptible cells, and the cDNA remained stable after it had been propagated in E. coli for 180 generations. Using this infectious JEV cDNA, we have successfully expressed a variety of reporter genes from the full-length genomic and various subgenomic RNAs in vitro transcribed from functional JEV cDNAS. In summary, we have developed a reverse genetics system for JEV that will greatly facilitate the research on this virus in a variety of different fields. It will also be useful as a heterologous gene expression vector and aid the development of a vaccine against JEV.

• The Journal of Korean Society of Virology
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• v.27 no.2
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• pp.197-207
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• 1997

To investigate the NS4 region of JEV, NS4 cDNA of K94P05 (JEV strain isolated from Korea in 1994) was amplified by RT-PCR and analyzed by sequencing PCR product. Genomic size of NS4 was 1212bp and nucleotide sequence was compared with that of other JEV strains. Nucleotide homology between JaOAr582 and K94P05 was 91.1% and that between Beijing and K94P05 was 89.8%, respectively. But the nucleotide sequence of E region of JaOAr582 and K94P05 showed 97.0% homology and that of Beijing and K94P05 did 95.8% homology. NS4 protein was expressed as a form of fusion protein by a prokaryotic expression system. The induced fusion product showed a lower molecular weight than predicted size and remained insoluble. The NS4 protein might be cleavaged by E. coli protease. Concluding above results, high hydrophobicity of the NS4 protein supported the fact that this protein played a role as a membrane component and the poor nucleotide sequence conservativity among JEV strains suggested that this region might be important to adapt each viral growth environment.

• Korean Journal of Veterinary Service
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• v.46 no.2
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• pp.115-122
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• 2023

This study was performed to investigate the distribution of mosquito vectors related to the zoonotic disease in Daejeon. Samples were taken using a blacklight trap once a month from March to November 2021 at the slaughterhouse in Daejeon. A total of 820 mosquitoes were captured and classified into 5 genera and 8 species. Among the collected mosquitoes, 319 (38.9%) and 295 (35.93%) were Aedes vexans nipponii and Culex pipiens pallens, respectively, making them the dominant species. The overall number of mosquitoes collected started to increase from May and reached the largest value of 329 (40.12%) in June. Trapped mosquitoes are created 72 pools by environmental condition and by species. The pools were tested by PCR methods for 7 zoonotic pathogens. Flavivirus-positive products were confirmed by DNA sequencing. Japanese encephalitis viruses were detected in 3 pools collected from cow lairage (Culex pipiens pallens) in May, cow by-product processing room (Aedes vexans nipponii) in June and cow lairage (Mansonia uniformis) in June. Culex flavivirus were detected in 4 pools. Based on the results of this study, it is considered that continous surveillence of mosquitoes in livestock assembly facilities (slaughterhouse) should be performed for controlling mosquito populations and mediating disease spread by mosquitoes.

• Pediatric Infection and Vaccine
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• v.23 no.1
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• pp.1-9
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• 2016

The Zika virus, a flavivirus related to dengue and Japanese encephalitis was discovered in the Zika forest in Uganda, 1947. Since Zika virus was first reported in Brazil in May 2015, infections have occurred in at least 40 countries, especially in the Americas. Zika virus infection usually is asymptomatic or causes mild illness, but may be related to severe clinical manifestations, particularly microcephaly and Guillain-$Barr{\acute{e}}$ syndrome. Although the possibility of autochthonous Zika virus transmission in South Korea is low, the imported cases and Zika virus-transmitting mosquito should be adequately monitored and promptly managed. In addition, enhancing preparedness for Zika virus infection are needed.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.365-368
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• 1992

1988년부터 1990년 6월까지 전국의 양돈장에서 수집된 돼지 유사산 태아 74복에서 바이러스성 원인체 분리 및 혈청학적 진단을 수행하였던 바 다음과 같은 결과를 얻었다. 공시한 74복의 유사산 태아중 44복의 태아 흉강액에서 면역 globulin이 검출되어 전염성 질병감염에 의한 유사산으로 추정되었다. 이중 37%가 바이러스성 유사산으로 나타났으며 유사산의 원인체별 분포를 살펴보면 돼지 파보바이러스가 21%로 가장 높았으며, 뇌심근염 바이러스가 11%, 일본뇌염 바이러스가 9% 등의 순으로 나타났다. 한편 돼지 콜레라바이러스 및 오제스키병 바이러스에 의한 유사산이 각각 1건씩 검출되었으며 동일 유사산 태아에서 2가지 병원체가 중복감염된 예도 관찰되었다.