Estimating the effects of variation in viremia on mosquito susceptibility, infectiousness, and R0 of Zika in Aedes aegypti.

Zika virus (ZIKV) is an arbovirus primarily transmitted by Aedes mosquitoes. Like most viral infections, ZIKV viremia varies over several orders of magnitude, with unknown consequences for transmission. To determine the effect of viral concentration on ZIKV transmission risk, we exposed field-derive...

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Bibliographic Details
Published in:PLOS Neglected Tropical Diseases
Main Authors: Blanka Tesla, Leah R Demakovsky, Hannah S Packiam, Erin A Mordecai, Américo D Rodríguez, Matthew H Bonds, Melinda A Brindley, Courtney C Murdock
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2018
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Online Access:https://doi.org/10.1371/journal.pntd.0006733
https://doaj.org/article/aa41050b0bf04f08b11a07ac45eda1f6
Description
Summary:Zika virus (ZIKV) is an arbovirus primarily transmitted by Aedes mosquitoes. Like most viral infections, ZIKV viremia varies over several orders of magnitude, with unknown consequences for transmission. To determine the effect of viral concentration on ZIKV transmission risk, we exposed field-derived Ae. aegypti mosquitoes to four doses (10(3), 10(4), 10(5), 10(6) PFU/mL) representative of potential variation in the field. We demonstrate that increasing ZIKV dose in the blood-meal significantly increases the probability of mosquitoes becoming infected, and consequently disseminating virus and becoming infectious. Additionally, we observed significant interactions between dose and days post-infection on dissemination and overall transmission efficiency, suggesting that variation in ZIKV dose affects the rates of midgut escape and salivary gland invasion. We did not find significant effects of dose on mosquito mortality. We also demonstrate that detecting virus using RT-qPCR approaches rather than plaque assays potentially over-estimates key transmission parameters, including the time at which mosquitoes become infectious and viral burden. Finally, using these data to parameterize an R0 model, we showed that increasing viremia from 10(4) to 10(6) PFU/mL increased relative R0 3.8-fold, demonstrating that variation in viremia substantially affects transmission risk.