wMel limits #zika and #chikungunya virus #infection in a #Singapore #Wolbachia-introgressed #Aedes aegypti strain, wMel-Sg (PLoS

(Source: PLoS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.)

OPEN ACCESS / PEER-REVIEWED / RESEARCH ARTICLE

wMel limits zika and chikungunya virus infection in a Singapore Wolbachia-introgressed Ae. aegypti strain, wMel-Sg

Cheong Huat Tan , PeiSze Jeslyn Wong , Meizhi Irene LI, HuiTing Yang, Lee Ching Ng , Scott Leslie O’Neill

Published: May 19, 2017 / https://doi.org/10.1371/journal.pntd.0005496 / This is an uncorrected proof.

Abstract

Background

Zika (ZIKV) and Chikungunya (CHIKV) viruses are emerging Aedes-borne viruses that are spreading outside their known geographic range and causing wide-scale epidemics. It has been reported that these viruses can be transmitted efficiently by Ae. aegypti. Recent studies have shown that Ae. aegypti when transinfected with certain Wolbachia strains shows a reduced replication and dissemination of dengue (DENV), Chikungunya (CHIKV), and Yellow Fever (YFV) viruses. The aim of this study was to determine whether the wMel strain of Wolbachia introgressed onto a Singapore Ae. aegypti genetic background was able to limit ZIKV and CHIKV infection in the mosquito.

Methodology/Principal findings

Five to seven-day old mosquitoes either infected or uninfected with wMel Wolbachia were orally infected with a Ugandan strain of ZIKV and several outbreak strains of CHIKV. The midgut and salivary glands of each mosquito were sampled at days 6, 9 and 13 days post infectious blood meal to determine midgut infection and salivary glands dissemination rates, respectively. In general, all wild type Ae. aegypti were found to have high ZIKV and CHIKV infections in their midguts and salivary glands, across all sampling days, compared to Wolbachia infected counterparts. Median viral titre for all viruses in Wolbachia infected mosquitoes were significantly lower across all time points when compared to wild type mosquitoes. Most significantly, all but two and one of the wMel infected mosquitoes had no detectable ZIKV and CHIKV, respectively, in their salivary glands at 14 days post-infectious blood meal.

Conclusions

Our results showed that wMel limits both ZIKV and CHIKV infection when introgressed into a Singapore Ae. aegypti genetic background. These results also strongly suggest that female Aedes aegypti carrying Wolbachia will have a reduced capacity to transmit ZIKV and CHIKV.

Author summary

Zika (ZIKV) and Chikungunya (CHIKV) viruses are emerging Aedes-borne viruses that are spreading outside their known geographic range and causing wide-scale epidemics. It has been shown that these viruses can be transmitted efficiently by Aedes aegypti. Recent studies have shown that Ae. aegypti when transinfected with certain Wolbachia strains shows a reduced replication and dissemination of several arboviruses, including dengue and yellow fever viruses. This study examines the effect of the wMel strain of Wolbachia in Singapore’s Ae. aegypti on susceptibility of these mosquitoes to ZIKV and CHIKV and finds that there is very strong inhibition of replication and dissemination of both viruses in mosquitoes that contain Wolbachia. Results from this study strongly suggest that female Ae. aegypti carrying Wolbachia will have a reduced capacity to transmit ZIKV and CHIKV. This indicates that establishment of Wolbachia in Ae. aegypti populations should reduce transmission of these viruses and presents a potential control measure in this setting.

_____

Citation: Tan CH, Wong PJ, LI MI, Yang H, Ng LC, O’Neill SL (2017) wMel limits zika and chikungunya virus infection in a Singapore Wolbachia-introgressed Ae. aegypti strain, wMel-Sg. PLoS Negl Trop Dis 11(5): e0005496. https://doi.org/10.1371/journal.pntd.0005496

Editor: Ann M. Powers, Centers for Disease Control and Prevention, UNITED STATES

Received: April 6, 2016; Accepted: March 15, 2017; Published: May 19, 2017

Copyright: © 2017 Tan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the paper and its Supporting Information files.

Funding: This study was funded by the Ministry of Finance, Singapore under the Reinvestment Fund (New approaches in dengue surveillance and control) as part of NEA’s feasibility study to determine the potential of Wolbachia as a biological control tool to suppress local Ae. aegypti population. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

–

Keywords: Chikungunya Fever; Zika Virus; Aedes Aegypti; Singapore; Wolbachia.

——-