Guidelines for efficacy testing of spatial repellents

Overview

 The term ‘spatial repellency’ is used here to refer to a range of insect behaviours induced by airborne chemicals that result in a reduction in human–vector contact and therefore personal protection. The behaviours can include movement away from a chemical stimulus, interference with host detection (attraction inhibition) and feeding response.

While many household insecticide products, such as mosquito coils, have been used for personal protection, most are based on the insecticidal activity (knock-down and mortality) of the active ingredient.

These guidelines are designed to extend those already recommended by WHO for testing the efficacy of household insecticide products. Expansion of those guidelines was required in order to promote and facilitate the discovery and development of novel active ingredients (AIs) with inherent spatial repellent properties for public health purposes and for further standardization of evaluation procedures for spatial repellency.

The document provides guidance and describes steps for laboratory testing and for semi-field and field evaluations of spatial repellent products (technical materials and formulated products) designed to provide protection in a specific space (indoor and/or outdoor) against mosquitoes. With some modifications, the guidelines can be used to determine the efficacy and personal protectiveness of candidate products against other flying nuisance pests. These guidelines may have to be modified when proof of principle is established (i.e. the public health value of spatial repellents for vector-borne disease control) and as new methods for assessing the spatial repellency of such products become available.

These guidelines are designed for using AIs that have already undergone safety assessment, including toxicity by inhalation. Nevertheless, any adverse-effects or undesirable characteristics observed during laboratory studies and field trials should be recorded and reported.