Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes.

During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing th...

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Bibliographic Details
Published in:PLOS Neglected Tropical Diseases
Main Authors: Yan-Jang S Huang, Susan M Hettenbach, So Lee Park, Stephen Higgs, Alan D T Barrett, Wei-Wen Hsu, Julie N Harbin, Lee W Cohnstaedt, Dana L Vanlandingham
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2016
Subjects:
Arctic medicine. Tropical medicine
RC955-962
Public aspects of medicine
RA1-1270
Arctic
Online Access:https://doi.org/10.1371/journal.pntd.0005038
https://doaj.org/article/24fd5122e4844ac380d9ee6a00caec09
Description
Summary:During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b), GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America.

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