Wolbachia reduces the transmission potential of Dengue-infected Aedes aegypti

Ye, Yixin H., Carrasco, Alison M., Frentiu, Francesca D., Chenoweth, Stephen F., Beebe, Nigel W., van den Hurk, Andrew F., Simmons, Cameron P., O'Neill, Scott L., & McGraw, Elizabeth A. (2015) Wolbachia reduces the transmission potential of Dengue-infected Aedes aegypti. PLoS Neglected Tropical Diseases, 9(6), e0003894.

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Abstract

BACKGROUND:

Dengue viruses (DENV) are the causative agents of dengue, the world's most prevalent arthropod-borne disease with around 40% of the world's population at risk of infection annually. Wolbachia pipientis, an obligate intracellular bacterium, is being developed as a biocontrol strategy against dengue because it limits replication of the virus in the mosquito. The Wolbachia strain wMel, which has been introduced into the mosquito vector, Aedes aegypti, has been shown to invade and spread to near fixation in field releases. Standard measures of Wolbachia's efficacy for blocking virus replication focus on the detection and quantification of virus in mosquito tissues. Examining the saliva provides a more accurate measure of transmission potential and can reveal the extrinsic incubation period (EIP), that is, the time it takes virus to arrive in the saliva following the consumption of DENV viremic blood. EIP is a key determinant of a mosquito's ability to transmit DENVs, as the earlier the virus appears in the saliva the more opportunities the mosquito will have to infect humans on subsequent bites.

METHODOLOGY/PRINCIPAL FINDINGS:

We used a non-destructive assay to repeatedly quantify DENV in saliva from wMel-infected and Wolbachia-free wild-type control mosquitoes following the consumption of a DENV-infected blood meal. We show that wMel lengthens the EIP, reduces the frequency at which the virus is expectorated and decreases the dengue copy number in mosquito saliva as compared to wild-type mosquitoes. These observations can at least be partially explained by an overall reduction in saliva produced by wMel mosquitoes. More generally, we found that the concentration of DENV in a blood meal is a determinant of the length of EIP, saliva virus titer and mosquito survival.

CONCLUSIONS/SIGNIFICANCE:

The saliva-based traits reported here offer more disease-relevant measures of Wolbachia's effects on the vector and the virus. The lengthening of EIP highlights another means, in addition to the reduction of infection frequencies and DENV titers in mosquitoes, by which Wolbachia should operate to reduce DENV transmission in the field.

Impact and interest:

11 citations in Scopus
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12 citations in Web of Science®

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ID Code: 88914
Item Type: Journal Article
Refereed: Yes
Keywords: Dengue, Wolbachia, Saliva, Mosquito, Biological Control
DOI: 10.1371/journal.pntd.0003894
ISSN: 1935-2735
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > MEDICAL MICROBIOLOGY (110800) > Medical Virology (110804)
Divisions: Current > Schools > School of Biomedical Sciences
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Funding:
Copyright Owner: Copyright: 2015 Ye et al.
Copyright Statement: 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.
Deposited On: 11 Oct 2015 23:34
Last Modified: 12 Oct 2015 21:57

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