#NS5 from #Dengue virus serotype 2 can adopt a conformation analogous to its #ZIKV and #JEV homologues (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

NS5 from Dengue virus serotype 2 can adopt a conformation analogous to its ZIKV and JEV homologues.

Abbas El Sahili, Tingjin Sherryl Soh, Jonas Schiltz, Aïcha Gharbi-Ayachi, Cheah Chen Seh, Pei-Yong Shi, Siew Pheng Lim, Julien Lescar

DOI: 10.1128/JVI.01294-19

 

ABSTRACT

Flavivirus non-structural protein 5 (NS5) contains a N-terminal methyltransferase domain (MTase) and a C-terminal polymerase domain (RdRp) fused through a nine-amino acid linker. While the individual NS5 domains are structurally conserved, in the full-length protein, their relative orientations fall into two classes: NS5 from JEV and ZIKV adopt one conformation, while NS5 from DENV3 another. Here, we report a crystallographic structure of NS5 from DENV2 in a conformation similar to the extended one seen in JEV and ZIKV NS5 crystal structures, albeit looser. Substituting DENV2 NS5 linker with DENV1, -3, -4, JEV and ZIKV NS5 linkers had modest or minimal effects on in vitro DENV2 MTase and RdRp activities. Heterotypic DENV NS5 linkers attenuated DENV2 replicon growth in cells, whilst JEV and ZIKV NS5 linkers abolished replication. Thus, JEV and ZIKV linkers likely hindered essential DENV2 NS5 interactions with other viral or host proteins within the virus replicative complex. Overall, this work sheds light on the dynamics of the multifunctional flavivirus NS5 protein and its interdomain linker. Targeting the NS5 linker is a possible strategy for producing attenuated flavivirus strains for vaccine design.

 

IMPORTANCE

Flaviviruses include important human pathogens such as dengue or Zika virus. NS5 is a non-structural protein essential for flavivirus RNA replication, with dual MTase and RdRp enzyme activity and thus constitutes a major drug target. Insights into NS5 structure, dynamics and evolution should inform the development of antiviral inhibitors and vaccine design. We found that NS5 from DENV2 can adopt a conformation resembling NS5 from JEV and ZIKV. Substitution of DENV2 NS5 linker with JEV and ZIKV NS5 linkers abolished DENV2 replication in cells, without significantly impacting in vitro DENV2 NS5 enzymatic activities. We propose that heterotypic Flavivirus NS5 linkers impeded DENV2 NS5 protein-protein interactions that are essential for virus replication.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Flavivirus; Dengue fever; Zika Virus; Japanese Encephalitis virus.

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Lethal #Encephalitis in #Seals with #JEV #Infection, #China, 2017 (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 25, Number 8—August 2019 / Dispatch

Lethal Encephalitis in Seals with Japanese Encephalitis Virus Infection, China, 2017

Xiangdong Li1, Mingming Qiao1, Xiaoyu Deng, Xi Chen, Shengyong Sun, Qian Zhang, Wenjie Zhang, Feifei Tan, Zhe Sun, Xizhao Chen, Ming Sun2  , and Kegong Tian2

Author affiliations: National Research Center for Veterinary Medicine, Luoyang, China (X. Li, F. Tan, Z. Sun, K. Tian); Beijing Anheal Laboratories Co. Ltd, Beijing, China (M. Qiao, X. Deng, Xi Chen, S. Sun, Q. Zhang, W. Zhang, Xizhao Chen, M. Sun); Henan Agricultural University, Zhengzhou, China (K. Tian)

 

Abstract

We isolated Japanese encephalitis virus (JEV) from brain samples of 2 seals with lethal encephalitis at Weihai Aquarium, Weihai, China, in 2017. We confirmed our findings by immunohistochemical staining and electron microscopy. Phylogenetic analysis showed this virus was genotype I. Our findings suggest that JEV might disseminate though infected zoo animals.

Keywords: Japanese Encephalitis Virus; Seals; Wildlife; Encephalitis.

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PD1+CCR2+CD8+ T Cells Infiltrate the #CNS during Acute #JEV #Infection (Virol Sin., abstract)

[Source: Virologica Sinica, full page: (LINK). Abstract, edited.]

PD1+CCR2+CD8+ T Cells Infiltrate the Central Nervous System during Acute Japanese Encephalitis Virus Infection

Authors: Fang Zhang, Linlin Qi, Tong Li, Xiaojing Li, Dan Yang, Shengbo Cao, Jing Ye, Bin Wei

Research Article / First Online: 18 June 2019

 

Abstract

Japanese encephalitis (JE) is a viral encephalitis disease caused by Japanese encephalitis virus (JEV) infection. Uncontrolled inflammatory responses in the central nervous system (CNS) are a hallmark of severe JE. Although the CCR2–CCL2 axis is important for monocytes trafficking during JEV infection, little is known about its role in CNS trafficking of CD8+ T cells. Here, we characterized a mouse model of JEV infection, induced via intravenous injection (i.v.) and delineated the chemokines and infiltrating peripheral immune cells in the brains of infected mice. The CNS expression of chemokines, Ccl2, Ccl3, and Ccl5, and their receptors, Ccr2 or Ccr5, was significantly up-regulated after JEV infection and was associated with the degree of JE pathogenesis. Moreover, JEV infection resulted in the migration of a large number of CD8+T cells into the CNS. In the brains of JEV-infected mice, infiltrating CD8+ T cells expressed CCR2 and CCR5 and were found to comprise mainly effector T cells (CD44+CD62L−). JEV infection dramatically enhanced the expression of programmed death 1 (PD-1) on infiltrating CD8+ T cells in the brain, as compared to that on peripheral CD8+ T cells in the spleen. This effect was more pronounced on infiltrating CCR2+CD8+ T cells than on CCR2−CD8+ T cells. In conclusion, we identified a new subset of CD8+ T cells (PD1+CCR2+CD8+ T cells) present in the CNS of mice during acute JEV infection. These CD8+ T cells might play a role in JE pathogenesis.

Keywords: Japanese encephalitis virus (JEV) – CD8+ T cell – CCL2 – CCR2 – PD-1

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Fang Zhang and Linlin Qi have contributed equally to this work.

Electronic supplementary material

The online version of this article ( https://doi.org/10.1007/s12250-019-00134-z) contains supplementary material, which is available to authorized users.

 

Notes

Acknowledgements

This work was supported by grants from the Key Research and Development Program of the Ministry of Science and Technology of China (2016YFD500407), Precision Medicine program of Ministry of Science and Technology of China (2016YFC0905902), and the National Natural Science Foundation of China (81630043, 81571552). We thank the Core Facility and Technical Support in the Wuhan Investigate of Virology. We are grateful to Ding Gao and Juan Min for technical support for flow cytometry and mass cytometry, as well as Xuefang An and Fan Zhang for valuable assistance in the animal studies.

Author Contributions

BW and JY conceptualized and designed the study. LLQ, TL and FZ performed the experiments in this study, and analyzed the data. SBC and JY contributed virus strain and virus infection techniques to this study. DY and XJL participated in part of experimental work. FZ wrote the manuscript. All authors read and approved the final manuscript.

 

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Animal and Human Rights Statement

The study was approved by the Animal Ethics Committee of Wuhan Institute of Virology. All institutional and national guidelines for the care and use of laboratory animals were followed.

Keywords: Japanese encephalitis; Viral pathogenesis; Animal models.

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Vector #Mosquito #Ecology and Japanese #Encephalitis Virus Genotype III Strain Detection from #Culex tritaeniorhynchus and #Pig in Huaihua, #China (Vector Borne Zoo Dis., abstract)

[Source: Vector Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

Vector Mosquito Ecology and Japanese Encephalitis Virus Genotype III Strain Detection from Culex tritaeniorhynchus and Pig in Huaihua, China

Chen Chen, Teng Zhao, Yuting Jiang, Chunxiao Li, Gang Wang, Jian Gao, Yande Dong, Dan Xing, Xiaoxia Guo, and Tongyan Zhao

Published Online: 10 Jun 2019 / DOI: https://doi.org/10.1089/vbz.2019.2453

 

Abstract

The Japanese encephalitis virus (JEV), a mosquito-borne zoonotic pathogen, is the major cause of viral encephalitis worldwide. An investigation of mosquito species diversity, JEV infection rate, and seasonal population fluctuations of Culex tritaeniorhynchus in Huaihua County, Hunan Province, China, revealed the distribution of vector mosquito populations and genotypes and molecular characteristics of current, common JEV strains in this region. Research on mosquito species diversity in different habitats in Huaihua revealed that local community composition was relatively simple, including five species from four genera (two Culex spp., one Anopheles sp., one Aedes sp., and one Armigeres sp.). Cx. tritaeniorhynchuswas clearly the dominant species comprising 94.2–98.6% of all specimens and was always the most common species captured in paddy fields, pigpens, and human dwellings. The seasonal abundance of Cx. tritaeniorhynchus was relatively even, with a single seasonal peak in late August. Two Huaihua JEV strains isolated from the mosquito and pig were highly congruent. The genetic affinities were determined by analyzing capsid/premembrane (C/PrM) and envelope (E) gene variation. The results showed that they were of genotype III and most closely related to the live, attenuated vaccine strains SAl4-14-2 and SA14 and JaGAr01. The Huaihua E protein shares high similarity (mosquito 98.8% and pig 97.6%) at the nucleotide level with the SA14-14-2 vaccine. Although we found that the E gene sequences of the Huaihua JEV mosquito strain and pig strain have 11 and 15 amino acid site substitutions compared with the SAl4-14-2 vaccine, key sites that associated with JEV’s antigenic activity and neurovirulence were unchanged. The SA14-14-2 vaccine should therefore be effective in preventing JEV infection in the Huaihua region.

Keywords: Japanese Encephalitis Virus; Mosquitoes; Culex spp.; Pigs; China.

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#Decreases in Both the #Seroprevalence of Serum #Antibodies and #Seroprotection against #Japanese #Encephalitis Virus among Vaccinated #Children (Virol Sin., abstract)

[Source: Virologica Sinica, full page: (LINK). Abstract, edited.]

Decreases in Both the Seroprevalence of Serum Antibodies and Seroprotection against Japanese Encephalitis Virus among Vaccinated Children

Authors: Ran Wang, Lyu Xie, Na Gao, Dongying Fan, Hui Chen, Peigang Wang, Hongning Zhou, Jing An

Research Article / First Online: 25 March 2019

 

Abstract

The incidence of Japanese encephalitis (JE) has significantly decreased in China due to JE vaccines. In this study, we investigated the post-JE vaccination seroprevalence and protection provided by vaccinated sera against Japanese encephalitis virus (JEV) to elucidate the persistence and waning of antibodies to JEV among JE-SA14-14-2-vaccinated children. A total of 300 serum samples were collected from vaccinated children aged 3–10 years in Zhaotong, Yunnan, China. The seroprevalence of anti-JEV antibodies was determined by enzyme-linked immune sorbent assay and plaque reduction neutralization test. The highest seropositivity of 82% was observed in vaccinated children during the first 0.5–1.5 years after booster vaccination. Then, the seropositivity began to decline and remained lower than the original level observed in the 0.5–1.5-year group. An association was found between the waning of seroprevalence and elapsed time of the post-booster vaccination. Similarly, the neutralizing antibody (nAb) titres gradually decreased over time, and the levels showed a positive correlation with the protective efficacy in mice. This finding suggests that nAbs play an important role in the antiviral process and that the nAb titre is an adequately credible parameter for evaluating the protective efficacy induced by the JE vaccine. Our results provide data that clarify the persistence and waning of antibodies to JEV, which may help elucidate the pathogenesis of JE.

Keywords: Japanese encephalitis virus (JEV) – SA14-14-2 – Seroprevalence – Neutralizing antibodies – Waning of antibody

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Ran Wang and Lyu Xie have contributed equally to this work.

 

Electronic supplementary material

The online version of this article ( https://doi.org/10.1007/s12250-019-00099-z) contains supplementary material, which is available to authorized users.

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Notes

Acknowledgements

This work was supported by grants from the National Natural Science Foundation of China (81471957, 81772172, 81671971, U1602223 and 81871641) and a grant from the Open Research Projects of Key Laboratory of Beijing Ditan Hospital, Capital Medical University (DTKF201705). These funding sources played no part in the decision to publish, data analysis, or writing of the manuscript.

Author Contributions

RW designed and performed the experiments, analysed the data and wrote the manuscript; LX collected serum samples, demographic information from the vaccinated children and informed consent; NG analysed the data. DF contributed reagents and materials; HC and PW helped with the experiments; HZ designed the research and organized the collaboration; JA principally designed the experiments, revised the manuscript, organized the collaboration and directed the project. All authors read and approved the final manuscript.

 

Compliance with Ethical Standards

Conflict of interest

The authors declare that there are no competing interests.

Animal and Human Rights Statement

All animal experiments were performed under approval of the Institutional Animal Care and Use Committee of Chinese Capital Medical University. All animal experiments were performed under diethyl ether anaesthesia, and all efforts were made to minimize suffering. This study was performed in strict accordance with institutional review board approval from the Ethics Committee of Yunnan Institute of Parasitic Diseases, China. Written informed consent for serum sample collection was obtained from the parents or legal guardians on behalf of the vaccinated children. Their guardians completed questionnaires including demographic information and their integrated JE vaccination history. According to records from the local Centre for Disease Control and Prevention, these children had received two doses of the SA14-14-2 JE vaccine (Chengdu Institute of Biological Products, China).

Keywords: Japanese Encephalitis; Vaccines; China; Seroprevalence.

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#Immunogenicity and #safety of #measles- #rubella #vaccine co-administered with attenuated Japanese #encephalitis SA 14–14–2 vaccine in infants aged 8 months in #China: a non-inferiority RCT (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

Immunogenicity and safety of measles-rubella vaccine co-administered with attenuated Japanese encephalitis SA 14–14–2 vaccine in infants aged 8 months in China: a non-inferiority randomised controlled trial

Yan Li, MD, Susan Y Chu, PhD, Chenyan Yue, MD, Kathleen Wannemuehler, PhD, Shuyun Xie, MD, Fubin Zhang, MD, Yamin Wang, MD, Yuxi Zhang, MD, Rui Ma, MD, Yumin Li, MD, Zhiping Zuo, MD, Lance Rodewald, MD, Qiyou Xiao, MD, Zijian Feng, MD, Huaqing Wang, MD, Zhijie An, MD

Published: March 01, 2019 / DOI: https://doi.org/10.1016/S1473-3099(18)30650-9

 

Summary

Background

In China, measles-rubella vaccine and live attenuated SA 14–14–2 Japanese encephalitis vaccine (LJEV) are recommended for simultaneous administration at 8 months of age, which is the youngest recommended age for these vaccines worldwide. We aimed to assess the effect of the co-administration of these vaccines at 8 months of age on the immunogenicity of measles-rubella vaccine.

Methods

We did a multicentre, open-label, non-inferiority, two-group randomised controlled trial in eight counties or districts in China. We recruited healthy infants aged 8 months who had received all scheduled vaccinations according to the national immunisation recommendations and who lived in the county of the study site. Enrolled infants were randomly assigned (1:1) to receive either measles-rubella vaccine and LJEV simultaneously (measles-rubella plus LJEV group) or measles-rubella vaccine alone (measles-rubella group). The primary outcome was the proportion of infants with IgG antibody seroconversion for measles 6 weeks after vaccination, and a secondary outcome was the proportion of infants with IgG antibody seroconversion for rubella 6 weeks after vaccination. Analyses included all infants who completed the study. We used a 5% margin to establish non-inferiority. This trial was registered atClinicalTrials.gov ( NCT02643433).

Findings

1173 infants were assessed for eligibility between Aug 13, 2015, and June 10, 2016. Of 1093 (93%) enrolled infants, 545 were randomly assigned to the measles-rubella plus LJEV group and 548 to the measles-rubella group. Of the infants assigned to each group, 507 in the measles-rubella plus LJEV group and 506 in the measles-rubella group completed the study. Before vaccination, six (1%) of 507 infants in the measles-rubella plus LJEV group and one (<1%) of 506 in the measles-rubella group were seropositive for measles; eight (2%) infants in the measles-rubella plus LJEV group and two (<1%) in the measles-rubella group were seropositive for rubella. 6 weeks after vaccination, measles seroconversion in the measles-rubella plus LJEV group (496 [98%] of 507) was non-inferior to that in the measles-rubella group (499 [99%] of 506; difference −0·8% [90% CI −2·6 to 1·1]) and rubella seroconversion in the measles-rubella plus LJEV group (478 [94%] of 507) was non-inferior to that in the measles-rubella group (473 [94%] of 506 infants; difference 0·8% [90% CI −1·8 to 3·4]). There were no serious adverse events in either group and no evidence of a difference between the two groups in the prevalence of any local adverse event (redness, rashes, and pain) or systemic adverse event (fever, allergy, respiratory infections, diarrhoea, and vomiting). Fever was the most common adverse event (97 [19%] of 507 infants in the measles-rubella plus LJEV group; 108 [21%] of 506 infants in the measles-rubella group).

Interpretation

The evidence of similar seroconversion and safety with co-administered LJEV and measles-rubella vaccines supports the co-administration of these vaccines to infants aged 8 months. These results will be important for measles and rubella elimination and the expansion of Japanese encephalitis vaccination in countries where it is endemic.

Funding

US Centers for Disease Control and Prevention, US Department of Health and Human Services; China–US Collaborative Program on Emerging and Re-emerging Infectious Diseases.

Keywords: Measles; Rubella; Japanese encephalitis; Vaccines; China.

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New #strains of Japanese #encephalitis virus circulating in #Shanghai, #China after a ten-year hiatus in local #mosquito #surveillance (Parasit Vectors, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Parasit Vectors. 2019 Jan 9;12(1):22. doi: 10.1186/s13071-018-3267-9.

New strains of Japanese encephalitis virus circulating in Shanghai, China after a ten-year hiatus in local mosquito surveillance.

Fang Y1, Zhang Y2, Zhou ZB1, Xia S1, Shi WQ1, Xue JB1, Li YY1, Wu JT1.

Author information: 1 National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 20025, People’s Republic of China. 2 National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 20025, People’s Republic of China. zhang1972003@163.com.

 

Abstract

BACKGROUND:

Continuous vector pathogen surveillance is essential for preventing outbreaks of mosquito-borne diseases. Several mosquito species acting as vectors of Japanese encephalitis virus (JEV), dengue virus, Zika virus, malaria parasites and other pathogens are primary mosquito species in Shanghai, China. However, few surveys of human pathogenic arboviruses in mosquitoes in Shanghai have been reported in the last ten years. Therefore, in this study, we evaluated mosquito activity in Shanghai, China during 2016 and tested for the presence of alphaviruses, flaviviruses, orthobunyaviruses and several parasitic pathogens.

RESULTS:

Five pooled samples were JEV-positive [4/255 pools of Culex tritaeniorhynchus and 1/256 pools of Cx. pipiens (s.l.)] based on analysis of the NS5 gene. Alphaviruses, orthobunyaviruses, Plasmodium and filariasis were not found in this study. Phylogenetic and molecular analyses revealed that the JEV strains belonged to genotype I. Moreover, newly detected Shanghai JEV strains were genetically close to previously isolated Shandong strains responsible for transmission during the 2013 Japanese encephalitis (JE) outbreak in Shandong Province, China but were more distantly related to other Shanghai strains detected in the early 2000s. The E proteins of the newly detected Shanghai JEV strains differed from that in the live attenuated vaccine SA14-14-2-derived strain at six amino residues: E130 (Ile→Val), E222 (Ala→Ser), E327 (Ser→Thr), E366 (Arg→Ser/Pro), E393 (Asn→Ser) and E433 (Val→Ile). However, no differences were observed in key amino acid sites related to antigenicity. Minimum JEV infection rates were 1.01 and 0.65 per 1000 Cx. tritaeniorhynchus and Cx. pipiens (s.l.), respectively.

CONCLUSIONS:

Five new Shanghai JEV genotype I strains, detected after a ten-year hiatus in local mosquito surveillance, were genetically close to strains involved in the 2013 Shandong JE outbreak. Because JEV is still circulating, vaccination in children should be extensively and continuously promoted. Moreover, JEV mosquito surveillance programmes should document the genotype variation, intensity and distribution of circulating viruses for use in the development and implementation of disease prevention and control strategies.

KEYWORDS: Culex pipiens; Culex tritaeniorhynchus; Japanese encephalitis; Mosquito-borne diseases; SA14-14-2

PMID: 30626442 DOI: 10.1186/s13071-018-3267-9

Keywords: Japanese Encephalitis; Arbovirus; Mosquitoes; China; Shanghai; Culex spp.

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Analysis of #Zika virus neutralizing #antibodies in normal healthy #Thais (Sci Rep., abstract)

[Source: Scientific Reports, full page: (LINK). Abstract, edited.]

Article | OPEN | Published: 21 November 2018

Analysis of Zika virus neutralizing antibodies in normal healthy Thais

Wannapa Sornjai,  Janejira Jaratsittisin,  Prasert Auewarakul,  Nitwara Wikan &  Duncan R. Smith

Scientific Reports, volume 8, Article number: 17193 (2018)

 

Abstract

Zika virus (ZIKV) infections have been reported from all over Thailand, but the number of reported cases remains low, suggesting a degree of immune protection against ZIKV infection. To address this possibility, the presence of ZIKV neutralizing antibodies was determined in serum from 135 healthy Thai adults with a plaque reduction neutralization test (PRNT), and a number of samples were subsequently analyzed for the presence of neutralizing antibodies to dengue virus (DENV) and Japanese encephalitis virus (JEV). Results showed that 70.4% (PRNT50 ≥ 10), 55.6 (PRNT50 ≥ 20) or 22.2% (PRNT90 ≥ 20) of the samples showed neutralizing antibodies to ZIKV. Detailed analysis showed no association between the presence of neutralizing antibodies to other flaviviruses (DENV, JEV) and the presence of ZIKV neutralizing antibodies. These results suggest that the level of ZIKV neutralizing antibodies in the Thai population is enough to dampen the transmission of the virus in Thailand.

Keywords: Zika Virus; Dengue Fever; Seroprevalence; Thailand.

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Changing #Geographic #Distribution of #JE Virus Genotypes, 1935–2017 (Vector Borne Zoo Dis., abstract)

[Source: Vector Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

Changing Geographic Distribution of Japanese Encephalitis Virus Genotypes, 1935–2017

Xiaoyan Gao, Hong Liu, Xiaolong Li, Shihong Fu, Lei Cao, Nan Shao, Weijia Zhang, Qianying Wang, Zhi Lu, Wenwen Lei, Ying He, Yuxi Cao, Huanyu Wang, and Guodong Liang

Published Online: 12 Sep 2018 / DOI: https://doi.org/10.1089/vbz.2018.2291

 

Abstract

Japanese encephalitis virus (JEV) is a representative virus of the JEV serogroup in genus Flavivirus, family Flaviviridae. JEV is a mosquito-borne virus that causes Japanese encephalitis (JE), one of the most severe viral encephalitis diseases in the world. JEV is divided into five genotypes (G1–G5), and each genotype has its own distribution pattern. However, the distribution of different JEV genotypes has changed markedly in recent years. JEV G1 has replaced G3 as the dominant genotype in the traditional epidemic areas in Asia, while G3 has spread from Asia to Europe and Africa and caused domestic JE cases in Africa. G2 and G5, which were endemic in Malaysia, exhibited great geographical changes as well. G2 migrated southward and led to prevalence of JE in Australia, while G5 emerged in China and South Korea after decades of silence. Along with these changes, JE occurred in some non-traditional epidemic regions as an emerging infectious disease. The regional changes in JEV pose a great threat to human health, leading to huge disease burdens. Therefore, it is of great importance to strengthen the monitoring of JEV as well as virus genotypes, especially in non-traditional epidemic areas.

Keywords: Japanese Encephalitis; Flavivirus.

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An #Outbreak of Japanese #Encephalitis in Adults in Northern #China, 2013: A Population-Based Study (Vector Borne Zoo Dis., abstract)

[Source: Vector-Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

An Outbreak of Japanese Encephalitis in Adults in Northern China, 2013: A Population-Based Study

Li Xiaolong, Gao Xiaoyan, Fu Shihong, Wang Huanyu, Lu Zhi, He Ying, Lei Wenwen, and Liang Guodong

Published Online: 9 May 2018 / DOI: https://doi.org/10.1089/vbz.2017.2251

 

Abstract

Background:

A Japanese encephalitis (JE) epidemic occurred in 2013 in China. The aim of this study was to determine the spatial–temporal pattern of JE cases in adults occurring in 2013, as well as identify potential hotspots of incidences in the afflicted regions in China.

Methods/Principal Findings:

To generate a spatial–temporal pattern of JE cases in China, epidemiological and demographic data between 2011 and 2013 were collected. Our results indicate that the total number of JE cases in 2013 was significantly higher compared with those in 2011 and 2012. While the incidence of JE in individuals aged less than 15 years decreased in 2013, the incidence rate increased substantially in those aged 15 years and older. The population aged over 40 years was associated with the greatest increase of JE. Demographic analysis revealed a consistent increase in the proportion of JE cases aged 15 years and older in 2013 (42%) compared with that in 2012 (15%). In addition, JE cases from areas located between 35°N, 114°E and 40°N, 120°E in northern China were found to account for 27.17% of total JE cases nationwide in 2013, compared with 2.21% and 3.13% in 2011 and 2012, respectively. In these northern regions, the group aged 15 years and older represents the predominant population with JE, accounting for 73% of total cases. Further cluster analysis identified a large number of hotspots of JE in adults (>15 years of age) in northern China.

Conclusions/Significance:

Unlike the JE epidemics primarily in children below 15 years old in southern China, a significant outbreak of JE occurred in northern China in 2013, with the older age groups being the primary population affected. The increasing incidence of JE in adults has become an important public health issue and poses a new challenge to the successful prevention and control of JE in China, as well as other countries in East Asia.

Keywords: Japanese Encephalitis; China.

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