An outbreak of Japanese encephalitis caused by genotype Ib Japanese encephalitis virus in China, 2018: A laboratory and field investigation
Open Access
- 26 May 2020
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLoS Neglected Tropical Diseases
- Vol. 14 (5), e0008312
- https://doi.org/10.1371/journal.pntd.0008312
Abstract
Although Japanese encephalitis virus genotype Ib (JEV GIb) has replaced JEV GIII as the dominant genotype in endemic areas of Asia, no JEV GIb has been isolated from JE cases and natural mosquitoes at the same time in an outbreak of JE. In this study, we conducted virological and molecular biological laboratory tests on JE case samples (serum/cerebrospinal fluid) and locally collected mosquito samples from the 2018 JE outbreak in Ningxia, China. The result of JEV IgM antibody detection showed that 96% (67/70) of the suspected cases were laboratory-confirmed JE cases. Of the mosquitoes collected from local environments, 70% (17400/24900) were Culex tritaeniorhynchus of which 4.6% (16 /348 of the pools tested) were positive for JEV, other mosquitoes were negative. JEVs isolated from both the human cases and C. tritaeniorhynchus specimens belong to JEV GIb and are in the same evolutionary clade according to molecular evolution analyses. JEV GIb was detected simultaneously from specimens of JE cases and mosquito samples collected in nature in this study, suggesting that the JE outbreak that occurred in Ningxia in 2018 was due to infection of JEV GIb. Japanese encephalitis virus (JEV) is recognized as an important encephalitis pathogen all over the world. Its genotype is divided into GI-V. In recent years, JEV GIb (a temperate genotype) has gradually replaced GIII as the prevalent strain in JE endemic areas. Although JEV GIb originated from tropical Asia along with JEV GIa, it has rapidly spread for its advantages in wintering and infecting vectors. Although there have been epidemics caused by JEV GI and GIII, there have been no reports of a JE outbreak caused by JEV GIb alone in northeastern Asia. However, a JE outbreak occurred in the Ningxia Hui Autonomous Region in northern China in summer 2018 which was the first outbreak in Ningxia in recent decades. This paper presents a series of laboratory and field studies of this outbreak. The strain isolated from JE cases as well as JEV detected in Culex tritaeniorhynchus collected from local areas in nature all belonged to JEV GIb and were in the same evolutionary clade. This is the first report of a JE outbreak caused by JEV GIb infection in northeastern Asia (latitude 35 ° 14’– 39 ° 23’ N, longitude 104 ° 17’– 107 ° 39’ E), which used to be a low endemic area of JEV GIII.Keywords
Funding Information
- the National Key Research and Development Program (2016YFD0500401)
- The National Science and Technology Major Project of China (2018ZX10711001)
- The National Science and Technology Major Project of China (2018ZX10101-002)
- Study on etiology, pathogenic mechanism and prevention and control of epidemic Japanese encephalitis in ningxia region, Key research project of ningxia science and technology in 2019 (2019BCG01003)
- National Natural Science Foundation of China (31900156)
- the Development Grant of State Key Laboratory of Infectious Disease Prevention and Control (2014SKLID103)
- the Development Grant of State Key Laboratory of Infectious Disease Prevention and Control (2015SKLID505)
This publication has 32 references indexed in Scilit:
- Southernmost Asia Is the Source of Japanese Encephalitis Virus (Genotype 1) Diversity from which the Viruses Disperse and Evolve throughout AsiaPLoS Neglected Tropical Diseases, 2013
- Phylogeography of Japanese Encephalitis Virus: Genotype Is Associated with ClimatePLoS Neglected Tropical Diseases, 2013
- Molecular Detection and Genotyping of Japanese Encephalitis Virus in Mosquitoes during a 2010 Outbreak in the Republic of KoreaPLOS ONE, 2013
- Molecular evidence for the occurrence of Japanese encephalitis virus genotype I and III infection associated with acute Encephalitis in Patients of West Bengal, India, 2010Virology Journal, 2012
- Emergence of Genotype I of Japanese Encephalitis Virus as the Dominant Genotype in AsiaJournal of Virology, 2011
- Emergence of Japanese encephalitis virus genotype V in the Republic of KoreaVirology Journal, 2011
- Genotype V Japanese Encephalitis Virus Is EmergingPLoS Neglected Tropical Diseases, 2011
- Identification and isolation of Genotype-I Japanese Encephalitis virus from encephalitis patientsVirology Journal, 2010
- The Neglected Arboviral Infections in Mainland ChinaPLoS Neglected Tropical Diseases, 2010
- Emerging flaviviruses: the spread and resurgence of Japanese encephalitis, West Nile and dengue virusesNature Medicine, 2004