Spatial Repellents for Arbovirus Control

Overview

Dengue viruses are the most medically important arthropod-borne pathogens worldwide, with transmission occurring in most tropical and sub-tropical regions. An estimated 390 million infections occur yearly. Although, there are considerable ongoing efforts to develop a vaccine, vector control remains the only option for reducing dengue virus (DENV) transmission and disease burden. The recent emergence of Aedes-borne Zika (ZIKV) and Chikungunya viruses (CHIKV) highlight need for novel vector control tools. The goal of this project is to determine the efficacy of a spatial repellent (SR) product (active ingredient transfluthrin) for reducing contact between household residents and vector mosquitos and as a result reduce DENV, ZIKV, and/or other Aedes-borne virus transmission. Henceforth the investigators will designate the combined risk of Aedes-borne dengue, Chikungunya, Zika virus transmission by (DCZV). Spatial repellency is used here as a general term to refer to a range of insect behaviors caused by airborne chemicals that reduce contact between people and disease vectors. This can include movement away from a chemical stimulus, and interference with host detection (attraction-inhibition) and/or feeding response.

Protection provided by this product will be measured using entomological and virological approaches, comparing entomological indices will be measured through standard household monitoring of Aedes aegypti population densities, while DCZV transmission will be measured through door-to-door surveillance for active dengue disease and through serological monitoring for DCZV exposure in a randomized cluster trial. The investigators will establish a cohort of 3,400 persons, primarily children 2-12 years of age and adults who have not been previously infected with DCZV who will provide annual blood samples when they are healthy (longitudinal cohort), whereas in the same clusters the investigators expect to monitor up to 27,500 residents for active dengue disease (febrile surveillance cohort). The cohort will be monitored for a period of 2 years. The use of spatial repellents has never been tested on a large scale to reduce disease and could change vector control practices worldwide, reducing the amount of chemical insecticides applied and also prevent the development of insecticide resistance. The investigators plan to implement a short questionnaire to determine levels of acceptability and perceived efficacy amongst participating households. The project will be carried out in the Amazonia City of Iquitos, Peru, which has a well-established infrastructure for studying urban dengue fever. The study will generate rigorous evidence, documenting and evaluating the impact of SR products on human infection rates, to be considered and used by academia, industry and public health key stakeholders at the global, regional, national and/or local level and drive efforts to acquire full recommendation of SR products for inclusion in disease control programs.