Experimental evaluation of a metofluthrin passive emanator against Aedes albopictus

• Type of Material: Article
• Authors: Olivia Zarella, Emory University; Uche Ekwomadu, Emory University; Yamila Romer, Emory University; Oscar D Kirstein, Emory University; Azael Che-Mendoza, Universidad Autónoma de Yucatán; Gabriela González-Olvera, Universidad Autónoma de Yucatán, Mérida; Pablo Manrique-Saide, Emory University; Gregor Devine, QIMR Berghofer Medical Research Institute; Gonzalo Vazquez Prokopec, Emory University
• Language: English
• Date: 2022-05-10
• Publisher: Public Library of Science (PLoS)
• Publication Version: Final Published Version
• Copyright Statement: © 2022 Zarella et al
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0267278
• Title of Journal or Parent Work: PLoS One
• Volume: 17
• Issue: 5
• Grant/Funding Information: This study was supported by a grant from USAID (AID-OAA-F-16-00094; Devine, PI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
• Keywords: metofluthrin passive emanator; Experimental evaluation
• Research Categories: Environmental Sciences

Abstract

Background With the recent occurrence of locally transmitted Aedes-borne viruses in the continental United States and Europe, and a lack of effective vaccines, new approaches to control Aedes aegypti and Aedes albopictus are needed. In sub-tropical urban settings in the US, Ae. albopictus is a dominant nuisance and arbovirus vector species. Unfortunately, the vector control toolbox against Ae. albopictus is not as well developed as for Ae. aegypti. Here, we evaluate the efficacy, longevity, and range of protectiveness of a novel passive metofluthrin emanator (10% active ingredient in a polyethylene mesh) against Ae. albopictus indoors and outdoors. Methods Four studies were conducted comparing the presence of the metofluthrin emanator to a control lacking emanator with interest in quantifying efficacy by human landing counts. Studies evaluated the effect of an emanator at varying distances from one or more human volunteers indoors and outdoors. Efficacy of emanators over time since activation was also evaluated. Results Mixed-effects models determined that sitting in close proximity to an emanator reduced landings by 89.5% outdoors and by 74.6% indoors. The emanator was determined protective when located immediately next to a human volunteer outdoors but not uniformly protective when located further away. The emanator was protective at all tested distances from the device indoors. Mortality of mosquitoes exposed to metofluthrin emanators was ~2x higher than those who were not exposed in indoor conditions. Finally, a Generalized Additive Model determined that emanators used continuously outdoors lost their effect after 2.5 weeks and stopped inducing paralysis in mosquitoes after 3.8 weeks of use. Conclusions We show strong and lasting efficacy of 10% metofluthrin emanators against field Ae. albopictus both in indoor and outdoor conditions. Metofluthrin emanators can protect people from Ae. albopictus bites, representing a viable option for reducing human-mosquito contacts at home and beyond.