DETERMINING A DIAGNOSTIC DOSE OF PIRIMIPHOS-METHYL FOR AEDES AEGYPTI USING TREATED BOTTLES1

There is a pressing need for innovative strategies to control arboviruses transmitted by Aedes aegypti. The modification of indoor residual spraying to target Ae. aegypti is one such strategy. A clinical trial quantifying the epidemiologic impact of targeted indoor residual spraying for Ae. aegypti control used a product with pirimiphos-methyl as the active ingredient in the city of Mérida, Mexico. To monitor the susceptibility of local Ae. aegypti populations over the course of the trial, we calculated a diagnostic dose for pirimiphos-methyl using the Centers for Disease Control and Prevention bottle assay. Two independent laboratories tested a series of 8 concentrations of pirimiphos-methyl, eliciting a range of mortality between 0% and 100% in an insecticide-susceptible reference strain of Ae. aegypti. The results suggested a diagnostic dose of 25 μg/ml at a diagnostic time of 30 min. This diagnostic dose of pirimiphos-methyl was used to monitor pirimphos-methyl susceptibility in Ae. aegypti throughout the trial.