Japanese encephalitis (JE) is a mosquito-borne zoonotic disease that affects approximately 50,000 people annually in Asia, causing 10,000 deaths. Considering the role of pigs as the virus-amplifying host and the economic loss in the swine industry, JE is an important disease for both public and animal health. A nationwide JE virus (JEV) vaccination program has been conducted annually for more than 30 years to prevent severe reproductive disorders in the Korean sow population. Remarkable progress in molecular biology has made it possible to analyze the genome of the vaccine strain at the nucleotide and amino acid levels. However, the scientific record of the current JEV veterinary vaccine has not been reported. Therefore, this article outlines the current JEV vaccine strain used in animals and discusses future directions for developing new veterinary JEV vaccines.
Animals ; Asia ; Asian Continental Ancestry Group* ; Encephalitis Viruses, Japanese ; Encephalitis, Japanese* ; Genome ; Humans ; Korea* ; Molecular Biology ; Swine ; Vaccination ; Vaccines* ; Zoonoses

Several species of animals, including horses and pigs, can be infected with Japanese encephalitis virus (JEV). Wild boars (Sus scrofa) are also considered to be an effective amplifying host for JEV in wild environments. In this study, 288 blood samples were collected from wild boars in eight Korean provinces, and antibodies against JEV were detected using a virus neutralizing assay. The results showed that 66.0% (190/288) of wild boars in Korea had neutralizing antibodies against JEV. We found no significant differences in the seroprevalence of JEV among provinces (p > 0.05). The results indicate that wild boars in Korea have been exposed to JEV, suggesting that these boars may play an important role in amplifying and carrying JEV to other regions of Korea. The result of this study may be helpful for planning preventive measures.
Animals ; Antibodies ; Antibodies, Neutralizing ; Asian Continental Ancestry Group ; Encephalitis Virus, Japanese ; Encephalitis, Japanese ; Horses ; Humans ; Korea ; Lifting ; Seroepidemiologic Studies ; Sus scrofa ; Swine ; Viruses

Multiplex reverse transcription-polymerase chain reaction (mRT-PCR) is currently available in virus detection and defined as the simultaneous amplification of two or more DNA/RNA targets in a single reaction vessel. In this study, we attempted to modify the conventional mRT-PCR technique on a basis of GenomeLab Genetic Analysis System (GeXP). Initially, we optimized the analytical validation of the GeXP analyzer and its design of workflow and simultaneously detected eight arboviruses that related to epidemic encephalitis by verifying the specificity of mRT-PCR with Japanese encephalitis virus(JEV) cell cultures and positive strains identified previously and determining the sensitivity with in vitro-transcribed RNA of serial dilutions. The GeXP system after optimization could amplify the specific fragments related to the viruses and exposed specifically a total of 13 target genes out of eight types of arboviruses at the level of 10(2) copies/microL, and the findings suggest that the novel protocol we developed can be high-throughput and highly specific and sensitive as well as quickness in screening of the encephalitis viruses, and is promising in detection of encephalitis-associated viruses for molecular epidemiological studies.
Arboviruses ; genetics ; isolation & purification ; Encephalitis Virus, Japanese ; genetics ; Encephalitis Viruses ; genetics ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Sensitivity and Specificity

The prM/E gene of DV2 was cloned into the JEV (SA14-14-2 strain) replicon vector which had been constructed previously, and the resulting recombinant plasmid was named pPartialdeltaprM/E. The constructed chimeric clone was linearized and then was transcripted into RNA in vitro. The produced RNA was transfected into BHK-21 cells. Five to seven days later, CPE could be observed on the transfected BHK-21cells, and then the supernatant containing the chimeric virus was collected. The Supernatant was inoculated to BHK-1 cells and C6/36 cells, respectively. CPE could be observed about 4 days post the infection of C6/36cell with the chimeric virus. The results from RT-PCR, IFA, Western blot showed that the virus contained the chimeric RNA and the envelop protein of DV2. However, the chimeric virus could not be passaged in BHK-21 cell. The successful construction of the infectious clone JE/DEN-2 laid the basis for the further research of the DV vaccine.
Animals ; Blotting, Western ; Cell Line ; Cricetinae ; Dengue Virus ; genetics ; Encephalitis Viruses, Japanese ; genetics ; Genetic Vectors ; genetics ; Reassortant Viruses ; genetics ; Recombination, Genetic ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

Immunizations are among the most cost-effective and widely used public health interventions. This is a report on the revision of recommendations for immunization in children by the Korean Pediatric Society. The new classification system of immunization and the new definition of each category of immunization were introduced. Immunization and vaccines were divided into 4 groups: 1) vaccines that should be given to all infants and children (BCG, hepatitis B vaccine, DTaP, Td, polio vaccine, Japanese encephalitis vaccine, MMR, varicella vaccine, influenza vaccine [6~23 months of age], and H. influenzae type b vaccine), 2) those recommended to all infants and children, but the decision of administration can be made by parents (pneumococcal conjugate vaccine, hepatitis A vaccine, influenza vaccine [healthy children > or = 24 months of age], rotavirus vaccine, and human papilloma virus vaccine), 3) those that should be given to high risk group (pneumococcal polysaccharide vaccine [high-risk patients > or = 24 months of age], influenza vaccine [high-risk patients > or = 24 months of age], and typhoid vaccine), and 4) those administered for the control of outbreaks or prevention of emerging infectious diseases (all the vaccines that are administered to infants and children can also be administered for the control of outbreaks or prevention of emerging infectious diseases). The immunization schedule recommended by the Korean Pediatric Society is presented. The new edition of the Korean guidelines for immunization in children including detailed descriptions of each vaccine will be published by the end of 2008.
Chickenpox Vaccine ; Child ; Communicable Diseases, Emerging ; Disease Outbreaks ; Encephalitis, Japanese ; Hepatitis A Vaccines ; Hepatitis B Vaccines ; Humans ; Immunization ; Immunization Schedule ; Infant ; Influenza Vaccines ; Influenza, Human ; Measles-Mumps-Rubella Vaccine ; Papilloma ; Parents ; Poliomyelitis ; Public Health ; Rotavirus ; Typhoid Fever ; Vaccination ; Vaccines ; Viruses

The Japanese encephalitis virus (JEV), a member of the Flaviviridae family and Flavivirus genus, is transmitted by mosquitoes. JEV, of which some 35,000 cases are recorded every year, is a positive RNA virus. Two types of JEV vaccines have been developed to prevent the onset of encephalitis in humans, namely formalin-inactivated and liveattenuated vaccines. JEV inactivated vaccines are usually made using the Nakayama-NIH or Beijing-1 strains of the JEV virus. In this study, the immunological response to the Nakayama-NIH and Beijing-1 strains was analyzed as part of the effort to compile basic data which could lead to the selection of a suitable vaccine strain. To this end, the virus titer of Beijing-1 was found to be two-fold higher than that of Nakayama-NIH by plaque assay. Moreover, Beijing-1-induced neutralizing antibodies showed a higher level of titers when confronted by Korean JEV isolates than Nakayama-NIH-induced neutralizing antibodies (1:320 vs. 1:160, respectively). However, as a minimum ratio of 1:10 neutralizing antibody titers are required to protect against JEV infection, both strains in effect exhibited a sufficient level of neutralizing antibody titers. What's more, Beijing-1 was found to induce a somewhat higher cytotoxic T lymphocyte (CTL) response than Nakayama-NIH. Taken together, this can be taken to mean that Beijing-1 may in fact be a more effective vaccine candidate strain when it comes to inducing a high level of protective immunity against JEV infection.
Antibodies, Neutralizing* ; Asian Continental Ancestry Group* ; Culicidae ; Encephalitis ; Encephalitis Virus, Japanese* ; Encephalitis, Japanese* ; Flaviviridae ; Flavivirus ; Humans ; Lymphocytes* ; RNA Viruses ; Vaccines ; Vaccines, Inactivated ; Viral Load

In 2004, 13 mosquito samples and 31 pig blood samples were collected at reveral districts, Gia Lai province for virus isolating. Isolating virus was carried out by Aedes albopictus clone C6/36 cells. Identifying virus was implemented by RT-PCR with generate primers of Alpha, Bunya, Flavi viruses and specific primers of Japanese encephalitis and Nam dinh virus. Result: one Japanese encephalitis virus strain was isolated from pig blood samples at Ia Grai, Gialai and six Nam dinh virus strains were isolated from Clux tritaeniorhynchus, Culex vishnui and Culex gelidus at Chu se, Gia Lai.
Encephalitis, Japanese ; Viruses

Haemagglutination Inhibition Technique was applied to study conversion anti-Japanese encephalitis (JE) virus antibodies in pigs in Hoai Duc, Ha Tay, in 2002. The results showed that antibody conversion in pigs occurs year-round. Vero and C6/36 cells were used to isolate JE virus. From 83 mosquito pools and 30 pig blood samples, 7 JE viruses strains were isolated from mosquito pools, and 4 JE viruses strains were isolated from pig blood samples. These JE viruses strains were isolated either in the epidemic or in the non epidemic season. Sequencing of E gene region of JE virus strains that were isolated from mosquitoes and pigs, circulating of genotype I of JE virus in North Vietnam in 2002
Encephalitis Virus, Japanese ; Encephalitis Viruses ; Encephalitis ; Viruses

The analysis of evolutionary of JE virus in the North Vietnam was examined through 1,000 nucleotides of the envelope gene region encoded the E protein. 9 JE virus strains isolated from Vietnamese patients were sequenced and compared with previous published JE virus strains. The results showed that the Vietnamese strains isolated from human brain between 1986 and 1989 clustered in genotype 3. The strains isolated from mosquitoes and pigs between 2001 and 2002 clustered in genotype 1. The emerging JE virus genotype 1 in the North Vietnam among isolates from mosquitoes and pigs in the last few years was recorded for the first time. But JE virus genotype 1 was not detected among isolates from Vietnamese JE patients so far
Encephalitis, Japanese ; epidemiology ; Viruses

Recently the reverse genetics system contributed to the progresses in the investigation of positive-stranded RNA viruses. Here, we report the successful construction of a stable full-length infectious cDNA clone of the live attenuated JEV vaccine strain SA14-14-2. The eleven kilobase viral RNA genome was reverse transcribed, amplified as four overlapping DNA fragments and successively ligated into the low copy number plasmid pACYC184, which contains the p15A origin of replication. In vitro-transcribed RNAs had a specific infectivity of approximately 104 PFU/microgram RNA, and the resulting virus exhibited growth kinetics and plaque morphology similar to the parental virus in cell culture. The structural and functional integrity of the cDNA clone was stably maintained even after at least 150 generations in Escherichia coli strain TOP10. The cDNA clone was engineered to contain single nucleotide change to create a XhoI site and knock out a XbaI site (A to C at nt 9134) acting as a genetic marker. This genetic marker was retained in the recovered progeny virus. Our results suggest that the instability of the full-length infectious JEV cDNA clone can be overcome by employing low copy number plasmid pACYC184. This infectious JEV cDNA clone will aid future studies of pathogenesis, virulence, and replication. Furthermore, it will facilitate the development of SA14-14-2 based recombinant vaccines.
Asian Continental Ancestry Group* ; Cell Culture Techniques ; Clone Cells* ; DNA ; DNA, Complementary* ; Encephalitis Virus, Japanese* ; Encephalitis, Japanese* ; Escherichia coli ; Family Characteristics ; Genetic Markers ; Genome ; Humans ; Kinetics ; Parents ; Plasmids* ; Replication Origin ; Reverse Genetics ; RNA ; RNA Viruses ; RNA, Viral ; Vaccines, Synthetic ; Virulence