Entomological Efficacy of Aerial Ultra-Low Volume Insecticide Applications Against Aedes aegypti (Diptera: Culicidae) in Mexico

Abstract

A cluster-randomized controlled trial quantified the entomological efficacy of aerial ultra-low volume (AULV) applications of the insecticide chlorpyrifos against Aedes aegypti in Puerto Vallarta, México, during November–October 2017. The trial involved 16 large (1 × 1 km) clusters distributed between treatment-control arms. Primary endpoint was the abundance of Ae. aegypti indoors (total adults, females, and blood-fed females) collected using Prokopack aspirators. After four consecutive weekly cycles of AULV, all adult Ae. aegypti infestation indices were significantly lower in the treatment arm (OR and IRR ≤ 0.28). Efficacy in reducing indoor Ae. aegypti increased with each weekly application cycle from 30 to 73% (total adults), 33 to 76% (females), and 45.5 to 89% (blood-fed females). Entomological indices remained significantly lower in the treatment arm up to 2 wk after the fourth spraying round. Performing AULV spraying can have significant and lasting entomological impact on Ae. aegypti as long as multiple (ideally four) spray cycles are implemented using an effective insecticide.

Sterile Insect Technique (SIT) against Aedes Species Mosquitoes: A Roadmap and Good Practice Framework for Designing, Implementing and Evaluating Pilot Field Trials

“…Ground or aerial adulticiding with ultra-low volume (ULV) spraying of pyrethroid or carbamate insecticides is usually employed during public health emergencies to reduce further human disease transmission. Depending on the Aedes species present, indoor or outdoor residual treatments can affect vector densities [68]. In some contexts, when the natural population of Aedes remains high all year long and where there is no evidence of insecticide resistance [69], adulticiding may be neccessary to reduce the wild population preceding the sterile male releases.…”

Mosquito Excito-Repellency: Effects on Behavior and the Development of Insecticide Resistance

“…Vector control programs have favored insecticides to control adults, mainly based on ultralow-volume (ULV) space application for outdoors in open spaces due to the ease of covering large areas in the shortest possible time and thermal fog indoors [26][27][28]. Aerial ultralowvolume (AULV) applications are also being tested in México [29]. Targeted indoor residual spraying (IRS, TIRS) is another control method with evidence of efficacy in México [30].…”