Japanese encephalitis virus genotype replacement, Taiwan, 2009-2010.
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ABSTRACT:
SUBMITTER: Chen YY
PROVIDER: S-EPMC3311176 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The residential regions of Yunnan province, canton of Jing Hong, in China were surveyed for Japanese encephalitis virus (JEV) infection in mosquito and swine vectors to determine the frequency of JEV-carrying zoonotic vectors in 2009-2010. A total of 21,500 mosquitoes were collected and divided by species, and brain tissue was collected from 108 stillborn piglets. The infection rates for the different JEV species were 13.2% for Culex tritaeniorhynchus, 2.7% for Anopheles sinensis, 0.7% for Armigeres subalbatus, and 18.5% for stillborn piglets. The complete genomes of two JEV samples that were collected in different seasons and different regions, Yunnan 0901 and Yunnan 0902, were sequenced from a pool of Culex mosquitoes and stillborn piglets that had been collected randomly from several piggeries. Multiple sequence alignment with 24 fully-sequenced genes and 93 complete sequences of the JEV-encoded E gene revealed nucleotide homologies ranging from 97.2-99.6% and 94.5-99.7% in mosquitoes and piglets, respectively, and deduced amino acid homologies ranging from 97.4-98.1% and 96.0-98.2%, respectively. Phylogenetic analyses of the Yunnan 0901 and Yunnan 0902 strains' full-length genomes and E gene sequences indicated that these strains are most closely related to six Chinese SA14-derived viruses, and distantly related to the Australian FU, vellore P20778, and Japanese Ishikawa strains, and the previously isolated YN86-B8639 strains. The phylogenetic relationships based on the full-length genome were similar to those found for the E gene, indicating that phylogenetic analysis of the E gene will be a useful approach for genotyping of JEV, but not to better understand the potential changes in the biological characteristics and genetic relationship of JEV isolates.
| S-EPMC3540924 | biostudies-literature
Project description:BACKGROUND: Several studies have shown that the predominant genotype of Chinese Japanese encephalitis virus (JEV) is evolving from genotype 3 to genotype 1. However, in recent years, almost all genotype 1 isolates were from mosquitoes, and genotype 1 has been less associated with human disease than genotype 3. This study reports the isolation of human genotype 1 JEV and its genetic characteristics to provide additional insights into human JE pathogens that are currently circulating in China. METHODS AND RESULTS: In 2009, 31 cerebrospinal fluid samples were collected from patients living in Yunnan and Shanxi provinces and were used to inoculate Aedes albopictus C6/36 cells for virus isolation. The JEV strains were identified using immunofluorescent assays and the reverse transcription-polymerase chain reaction. Phylogenetic analyses based on the partial capsid/pre-membrane and full envelope (E) sequences were performed using Clustalx 1.8 software. Three JEV isolates were obtained from a 4-year-old girl and a 2-year-old boy living in Yunnan and an 82-year-old woman in Shanxi. The boy had been immunized with one dose of JE live attenuated vaccine. New isolates were grouped into genotype 1. Amino acid sequence for the viral E protein indicated 95% to 100% identity with each other and with other JEV strains. When compared with a consensus sequence of E protein, two amino acid substitutions were found: Ser(E-123)-Asn in the two Yunnan isolates and Lys(E-166)-Arg in the Shanxi isolate. CONCLUSIONS: Our findings indicate that the genotype 1 of JEV is causing human infections in China. Our observation of a previously vaccinated boy developing JE from genotype 1 virus infection also calls for more detailed studies, both in vitro and in vivo neutralization tests as well as active surveillance, to examine the possibility of a lack of complete protection conferred by the live attenuated JE vaccine against genotype 1 virus.
| S-EPMC3026811 | biostudies-literature
Project description:BackgroundJapanese encephalitis (JE) was once epidemic in most areas of China, including Wuhan, a city located in the central part of China. The incidence of JE dramatically decreased due to nationwide immunization with the live attenuated JE virus (JEV) vaccine, and no JE cases were reported during 2005-2008 in Wuhan. In 2009 and 2010, 31 JE cases reoccurred in this area. In this study, we investigated the causes of JE recurrence.Methods and findingsAll JE cases were laboratory-confirmed by detecting the JEV-specific IgM antibody with an IgM-capture enzyme-linked immunosorbent assay (ELISA). All patients were children between 2 months and 9 years of age with a median age of 2 years. Of the 31 cases, 9 had received one or two doses of the JEV vaccine, 11 had not been immunized previously with the JEV vaccine, and 11 had an unclear immunization history. Through reverse transcription polymerase chain reaction (RT-PCR), sequencing, and phylogenetic analysis, two new strains of JEV were isolated from Culex tritaeniorhynchus and identified as genotype 1 JEV, rather than genotype 3, which circulated in this area previously.ConclusionsVaccine failure or missed vaccination may have caused JE recurrence. Local centers for disease control and prevention need to improve immunization coverage, and the efficacy of the JE vaccine needs to be reevaluated in a population at risk for disease.
| S-EPMC3541373 | biostudies-literature
Project description: Not available
| S-EPMC2953986 | biostudies-literature
Project description:Japanese encephalitis (JE) is a global public health issue that has spread widely to more than 20 countries in Asia and has extended its geographic range to the south Pacific region including Australia. JE has become the most important cause of viral encephalitis in the world. Japanese encephalitis viruses (JEV) are divided into five genotypes, based on the nucleotide sequence of the envelope (E) gene. The Muar strain, isolated from patient in Malaya in 1952, is the sole example of genotype V JEV. Here, the XZ0934 strain of JEV was isolated from Culex tritaeniorhynchus, collected in China. The complete nucleotide and amino acid sequence of XZ0934 strain have been determined. The nucleotide divergence ranged from 20.3% to 21.4% and amino acid divergence ranged from 8.4% to 10.0% when compared with the 62 known JEV isolates that belong to genotype I-IV. It reveals low similarity between XZ0934 and genotype I-IV JEVs. Phylogenetic analysis using both complete genome and structural gene nucleotide sequences demonstrates that XZ0934 belongs to genotype V. This, in turn, suggests that genotype V JEV is emerging in JEV endemic areas. Thus, increased surveillance and diagnosis of viral encephalitis caused by genotype V JEV is an issue of great concern to nations in which JEV is endemic.
| S-EPMC3130007 | biostudies-literature
Project description:Japanese encephalitis virus Genome sequencing and assembly
| PRJNA855038 | ENA
Project description: Not available
| S-EPMC3204761 | biostudies-literature
Project description:The virulence of genotype I (GI) Japanese encephalitis virus (JEV) is under debate. We investigated differences in the virulence of GI and GIII JEV by calculating asymptomatic ratios based on serologic studies during GI- and GIII-JEV endemic periods. The results suggested equal virulence of GI and GIII JEV among humans.
| S-EPMC5652437 | biostudies-literature
Project description:BackgroundJapanese encephalitis virus (JEV) is an arthropod-borne virus causing serious public health issues in Asia. JEV consists of five genotypes and recent studies have shown the emergence of JEV genotype I (GI) and its replacement of genotype III (GIII). Using an archival JEV collection, we investigated the molecular evolution of JEV in Vietnam over the last 48 years (1964-2012) in humans, mosquitoes, and pigs, within the global context.MethodsThe nine JEV isolates from humans, pigs, and mosquitoes sequenced in this study and 29 sequences available in GenBank were used to analyze the envelope (E) protein of the Vietnamese JEVs. A collection of 225 cerebrospinal fluid specimens from patients with suspected Japanese encephalitis (JE) was also tested and genotyped with real-time RT-PCR.ResultsThe 38 E genes identified with sequencing and nine Vietnamese JEV strains genotyped with real-time RT-PCR, belonging to two lineages, evolved in accordance with those in the rest of the world. The first GIII strain was detected in humans in Vietnam in 1964, and in mosquitoes in 1979, whereas GI strains were first detected in humans and mosquitoes in 1990 and 1994, respectively. After 2004, GI was the only genotype detected in Vietnam, demonstrating that the GIIII strains had been displaced by GI strains. Five haplotypes were identified in the Vietnamese JEVs, with SKSS predominant. The S123N and S123R substitutions in the E protein were already present in the Vietnamese JEVs.ConclusionThis study describes the long evolutionary history of JEV in Vietnam over 34 years, which correlates well with the global evolution of JEV. The Vietnamese GIII strains have been replaced by GI strains in mosquitoes, pigs, and humans. The predominant haplotypes of the Vietnamese strains support this genotype displacement in Vietnam. Further surveillance is required to confirm the disappearance of the GIII strains in nature and the emergence of new pathogens causing encephalitis in Vietnam, after the long-term use of JEV vaccines in that country.
| S-EPMC4417254 | biostudies-literature
Project description:Historically, Japanese Encephalitis virus (JEV) genotype III (GIII) has been responsible for human diseases. In recent years, JEV genotype I (GI) has been isolated from mosquitoes collected in numerous countries, but has not been isolated from patients with encephalitis. In this study, we report recovery of JEV GI live virus and identification of JEV GI RNA from cerebrospinal fluid (CSF) of encephalitis patients in JE endemic areas of China. Whole-genome sequencing and molecular phylogenetic analysis of the JEV isolate from the CSF samples was performed. The isolate in this study is highly similar to other JEV GI strains which isolated from mosquitoes at both the nucleotide and deduced amino acid levels. Phylogenetic analysis based on the genomic sequence showed that the isolate belongs to JEV GI, which is consistent with the phylogenetic analysis based on the pre-membrane (PrM) and Glycoprotein genes. As a conclusion, this is the first time to isolate JEV GI strain from CSF samples of encephalitis patients, so continuous survey and evaluate the infectivity and pathogenecity of JEV GI strains are necessary, especially for the JEV GI strains from encephalitis patients. With respect to the latter, because all current JEV vaccines (live and inactivated are derived from JEV GIII strains, future studies should be aimed at investigating and monitoring cross-protection of the human JEV GI isolates against widely used JEV vaccines.
| S-EPMC3002311 | biostudies-literature