Volatile pyrethroids as a potential mosquito abatement tool: A review of pyrethroid-containing spatial repellents

Abstract

Ongoing difficulties with successful urban mosquito management highlights the need to find novel management strategies to reduce the impact of mosquito vectors. To date, urban mosquito management can be summarized as dependent on the theme of recruiting the public to invest in their own protection. This effort takes the form of source reduction education programs and accompanying personal protection guidelines. However, the topical repellents that form the cornerstone of our personal protection guidelines are available in equal measure with spatial repellents. Spatial repellents commonly include volatile pyrethroids as active ingredients, which easily transition into a vapor phase, that are formulated into mosquito coils, vaporizers, emanators, or heated mats. These formulations are available on the global market. Consumers frequently choose spatial repellents, and existing literature indicates this choice has merits. This predicament forces integrated vector management to adapt to and understand tools that consumers selectively employ. At present, there is little information differentiating the effects of vapor-active pyrethroids from the contact efficacies we recognize from well-utilized pyrethroids. To address this, volatile pyrethroids need to have their multiple effects identified, defined, and described to maximize their utility for preventing mosquito biting and, thus, pathogen transmission. This article reviews the known utility of volatile pyrethroids in the context of repellency, acute symptoms, toxicity, and sublethal effects, and provides an overview of the evaluation methods used with volatile pyrethroids.