• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1120-1125
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• 2022

Japanese encephalitis virus (JEV), the causative agent of Japanese encephalitis (JE), is an importantly zoonotic, vector-borne virus widely prevalent in Asia. Although JE has been well controlled in China, its prevalence remains a huge threat to the pig industry as well as human health. Herein, we report on our molecular and serological investigations of JEV among pigs from different regions in Hunan Province of China from 2019 to 2021. Collectively, 19.27% (583/3026, 95% Confidential Interval (CI) 17.86-20.68) of sampled pigs were positive for JEV IgG antibody as revealed by indirect enzyme-linked immunosorbent assay, and the seroprevalence of JEV among pigs was significantly associated with the development stage and breeding scale (p < 0.01). Meanwhile, 10.99% (42/382, 95% CI 7.86-14.13) of tissue samples of pigs with suspected clinical symptoms of JE and 23.44% (15/64, 95% CI 13.06-33.82) of mosquito batches were JEV-positive via reverse polymerase chain reaction. In addition, the complete E gene sequences of 14 JEV strains identified in this study were amplified and sequenced. Phylogenetic analysis showed that all 14 JEV strains belonged to genotype I-b and displayed a distinct genetic relationship to the present JEV vaccine strain (SA14-14-2). In conclusion, our results revealed not only the severe prevalence of JEV in Hunan Province, but also that JEV I-b might be the predominant genotype in Hunan Province, suggesting therefore that effective measures for JE control are urgently needed.

• Korean Journal of Veterinary Research
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• v.62 no.3
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• pp.19.1-19.6
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• 2022

Japanese encephalitis virus (JEV) and Akabane virus (AKAV) are mosquito-borne viruses that cause encephalitis and reproductive disorders in horses and cattle, respectively. There is no treatment for JEV or AKAV infections in animals. Therefore, we evaluated the antiviral activity of 18-mer amphipathic peptides in the 1b-4/21-C series on JEV and AKAV using Vero cells in vitro and evaluated their effects on JEV in mice. Of 6 peptides, 1b-4/21-C12 had the lowest IC₅₀ of 0.313 against JEV and its use as an antiviral against JEV and AKAV was examined. The IC₅₀ of 1b-4/21-C12 against JEV and AKAV was 0.78 and 1.14 µM, respectively. Mice treated with 5 or 2 mg/kg of 1b-4/21-C12 had 32% and 16% survival rates, respectively, and the surviving mice treated with 1b-4/21-C12 began to gain weight beginning 8 days post challenge with the virulent Nakayama strain. Moreover, 20 µM 1b-4/21-C peptide had no cytotoxic effects on Vero cells. Our in vitro and in vivo results indicate that 1b-4/21-C12 has antiviral activity against enveloped JEV and AKAV and might be useful as a therapeutic substance.

• IMMUNE NETWORK
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• v.12 no.2
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• pp.48-57
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• 2012

Acute viral encephalitis caused by neurotrophic viruses, such as mosquito-borne flaviviruses, is an emerging and re-emerging disease that represents an immense global health problem. Considerable progression has been made in understanding the pathogenesis of acute viral encephalitis, but the immune-pathological processes occurring during the progression of encephalitis and the roles played by various molecules and cellular components of the innate and adaptive systems still remain undefined. Recent findings reveal the significant contribution of Toll-like receptors (TLRs) and regulatory $CD4^+$ T cells in the outcomes of infectious diseases caused by neurotrophic viruses. In this review, we discuss the ample evidence focused on the roles of TLRs and $CD4^+$ helper T cell subsets on the progression of acute viral encephalitis. Finally, we draw attention to the importance of these molecules and cellular components in defining the pathogenesis of acute viral encephalitis, thereby providing new therapeutic avenues for this disease.

• Toxicological Research
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• v.13 no.3
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• pp.275-279
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• 1997

The acute toxicity of the combined vaccine (KGCC-95VI) for the prophylaxis against Japanese encephalitis and Hantaan virus infection. recently developed by Korea Green Cross Corporation, was investigated. KGCC-95VI was administered to the Balb /c mice in two routes, orally and subcutaneously, and into the New Zealand White rabbits subcutaneously. $LD_{50}$ was not accessible as there were no deaths in the group treated even at a dose 800 times the expected clinical dose in both animal species. Between the treated and control groups there were no statistically significant differences in body weight changes and clinical signs during the 14-day observation period, and no pathological gross findings. Accordingly KGCC-95VI is considered not to have the acute toxicity in mice and rabbits.

• Toxicological Research
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• v.13 no.4
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• pp.353-357
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• 1997

The possibility of the allergic encephalomyelitis caused by the combined vaccine (KGCC95VI) for the prophylaxis against Japanese encephalitis and Hantaan virus infection, recently developed by Korea Green Cross Corporation, was investigated in the Hartley guinea pigs. The KGCC-95VI was administered to the guinea pigs subcutaneously to sensitize the animals three times at one month intervals. There were no clinical signs or gross pathological findings. There were no abnormal histopathological findings at cerebrums, cerebellums, brain stems and the spinal cords. The concentration of myelin basic protein was 1.10 ng/dose quantified by ELISA, which met the guide4ine of below 2 ng/ml/dose recommended by American Society of Health -System Pharmacists(AHPS) Drug Information. Accordingly, the KGCC-95VI is considered not to induce any allergic immune responses which may lead to the experimental allergic encephalomyelitis.

• Korean Journal of Veterinary Service
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• v.26 no.1
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• pp.11-18
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• 2003

A total of 1,024 sera were collected from cattle(227), pigs(465), chickens(257) and dogs(75) raised or slaughtered in Daejeon metropolitan city from April to September 2002. Japanses encephalitis virus(JEV) antibodies in sera were detected by the haemagglutination inhibition test. The prevalence rates of JEV antibodies were 99.1 %, 54.0 %, 63.0 % and 98.7 % in cattle, pigs, chickens and dogs, respectively. In case of cattle and dogs, the monthly antibody-positive rates were as high as 85.7∼100.0 % and there were no differences among six months. In case of pigs, the monthly antibody-positive rate showed the lowest in April(6.4 %) and the highest in July(100.0 %) and it remained above 50 % during the summer-time. In case of chickens, the monthly antibody-positive rate was 100.0 % in July & August, 80.5 % in June, 40.0 % in May, 7.5 % in September and 5.0 % in April in order and there were distinct differences in seasons.

• Korean Journal of Veterinary Service
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• v.35 no.3
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• pp.169-174
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• 2012

Japanese encephalitis virus (JEV) is one of the main causes of viral encephalitis in human and animals. For over 30 years, a live attenuated JEV vaccine strain has been used in the veterinary field, and it is required to conduct quality evaluation studies on the commercial vaccines. For the quality control of live attenuated JEV vaccine, we investigated the nucleotide sequence similarity of prME gene derived from five JEV vaccines commercially available in pigs in Korea. The Vero cells infected with JEV vaccines showed specific cytopathic effect, which was characterized by rounding and detached cells. In the phylogenetic analysis, all of the vaccine strains showed a close relationship with the original vaccine seed strain (Anyang 300) and clustered into the genotype 3. In comparison of the nucleotide and deduced amino acid sequences of prME genes with the original strain, all JEV vaccine strains showed high amino acid similarity ranging from 98.9% to 99.5%, but had several point mutations, probably due to high mutation rates of viral RNA polymerase by several virus passages. Even though the current JEV vaccine strains have been maintained and produced for a long period of time, the genetic characterization of them have been rarely changed. However, since the mid 1990's, molecular epidemiology of JEV has been changed sharply from genotype 3 to genotype 1 in Korea, further studies on new vaccine strains to genotype 1 is required for more effective prevention in the field.

• Molecules and Cells
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• v.21 no.1
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• pp.112-120
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• 2006

It has been suggested that defective interfering (DI) RNA contributes to the persistence of Japanese encephalitis virus (JEV). In this study, we characterized molecular and biological aspects of the DI RNA and its relation to viral persistence. We identified a homologous DI virus intimately associated with JEV persistence in Vero cells. The production of DI RNA during undiluted serial passages of JEV coincided with the appearance of cells refractory to acute infection with JEV. We also established a Vero cell clone with a persistent JEV infection in which the DI RNA coreplicated efficiently at the expense of helper virus. The infectious virus yield of the clone fluctuated during its growth depending upon the amount of DI RNA accumulated in the previous replication cycle. Identification of the corresponding negative-sense RNA of the DI RNA indicated that the DI RNA functioned as a replication unit. Most of the DI RNA molecules retained their open reading frames despite a large deletion, encompassing most of the prM, the entire E, and the 5' half of the NS1 gene. Taken together, these observations suggest that the generation of homologous DI RNA during successive JEV acute infections in Vero cells probably participates actively in persistent JEV infection.

• Annals of Clinical Neurophysiology
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• v.16 no.1
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• pp.35-38
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• 2014

Japanese-B viral encephalitis (JE) usually has a monophasic illness pattern. A 45-year-old woman in an altered mentality had improved over 1 month. About 1 week after the initial improvement, the patient became comatose with aggravated EEG and MRI findings. Assays of cerebrospinal fluid and serum were positive for the IgM antibody to Japanese-B virus. After intravenous immunoglobulin (IVIG) infusion, the patient recovered. We report a patient with JE who showed a biphasic illness pattern and recovered after IVIG therapy.

• The Journal of the Korean Society for Microbiology
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• v.3 no.1
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• pp.51-65
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• 1968

The site of the synthesis of Japanese encephalitis virus(JEV) in the actinomycin-treated and infecter PS Y15 cells(a porcine kidney stable cell line) was observed by the immunofluorescent antibody technique, acridine orange staining, and the autoradiographic analysis. In the parallel studies by immunofluorescent technique and acridine orange staining it the infected cells, Viral protein(as an antigen) and viral RNA were detected at the same site of cytoplasm. In the autoradiographic analysis, the cytoplasmic labeling of $^3H$-uridine was due to the synthesis of JEV-RNA, while the nucleolus and nucleus were not involved. In the autoradiographic studies on the secton of infected cells, the $^3H$-uridine was frequently incorporated around the cytoplasmic vacuoles. This localization of labeling agreed with the site of acridine orange positive granules. The results suggest that the syntheses of the viral RNA and viral protein occurred in the similar site of cytoplasm of the infected cells, and also the virus particles seem to be assembled in the sites of the viral RNA and protein syntheses.