CHAPTER 1 - Arthropod repellents in public health

Abstract

This chapter will briefly review the role, types of arthropod repellents, and discuss their important role in personal protection from vectors and vector-borne diseases. Applying repellents to exposed skin provides personal protection from bites and will reduce the risk of contracting arthropod-borne diseases. Studies have been conducted to investigate whether the use of repellents can reduce the incidence of such diseases at a population level in endemic regions, but further work is needed to fully quantify their benefit as a sustainable public health measure. One limiting factor to the efficacy of arthropod repellents is the bite avoidance behavior adopted by individuals, particularly in terms of appropriate and regular application of repellents that some studies have shown to be suboptimal. A further consideration is the means by which arthropod repellents are assessed and compared, which is discussed. For the user, a repellent formulation must demonstrate an effective dose to completely prevent arthropod bites, which is easily achieved by the user, and the four most widely available active ingredients do have this property if present in sufficient concentrations in a marketed formulation, in many countries being controlled by regulatory agencies. Having achieved a high level of repellency, this should be sustained for a reasonable time before reapplication, which is dependent upon not only the dose of repellent formulation applied, but also a host of other environmental factors. This aspect is explored in the text and implications for manufacturers and users of arthropod repellent products are discussed.