Evaluating the feasibility of using insecticide quantification kits (IQK) for estimating cyanopyrethroid levels for indoor residual spraying in Vanuatu

Abstract

BackgroundThe quality of routine indoor residual spraying (IRS) operations is rarely assessed because of the limited choice of methods available for quantifying insecticide content in the field. This study, therefore, evaluated a user-friendly, rapid colorimetric assay for detecting insecticide content after routine IRS operations were conducted.MethodsThis study was conducted in Tafea Province, Vanuatu. Routine IRS was conducted with lambda cyhalothrin. Two methods were used to quantify the IRS activities: 1) pre-spray application of small felt pads and 2) post-spray removal of insecticide with adhesive. The insecticide content was quantified using a colorimetric assay (Insecticide Quantification Kit [IQK]), which involved exposing each sample to the test reagents for 15 mins. The concentration of insecticide was indicated by the depth of red colour.ResultsThe IQK proved simple to perform in the field and results could be immediately interpreted by the programme staff. The insecticide content was successfully sampled by attaching felt pads to the house walls prior to spraying. The IRS operation was well conducted, with 83% of houses being sprayed at the target dose (20 – 30 mg AI/m2). The average reading across all houses was 24.4 ± 1.5 mg AI/m2. The results from the felt pads applied pre-spray were used as a base to compare methods for sampling insecticide from walls post-spray. The adhesive of Sellotape did not collect adequate samples. However, the adhesive of the felt pads provided accurate samples of the insecticide content on walls.ConclusionThe IQK colorimetric assay proved to be a useful tool that was simple to use under realistic field conditions. The assay provided rapid information on IRS spray dynamics and spray team performance, facilitating timely decision making and reporting for programme managers. The IQK colorimetric assay will have direct applications for routine quality control in malaria control programmes globally and has the potential to improve the efficacy of vector control operations.

DDT-based indoor residual spraying suboptimal for visceral leishmaniasis elimination in India

“…Samples to determine the concentration of DDT delivered to walls during IRS were collected from wall surfaces using 5-cm 2 Bostik tape discs, as described by Russell et al (51). Briefly, two discs per sample (10 cm 2 in total) were placed onto the wall surface and rubbed firmly.…”

Identification of Optimal Frequencies to Determine Alpha-Cypermethrin Using Machine Learning Feature Selection Techniques

“…Furthermore, IRS operators can become sensitised to QA methods used and focus spray efforts on filter papers, providing artificial results. Alternative methods such as the Insecticide Quantification Kit (IQK) have been developed and used in a few field surveys [4].…”

Determination of the amount of insecticide picked up by mosquitoes from treated nets

“…5). [26,27,32,33,38,44,45]. As the new combined tools are introduced, detection of active ingredients that actually come into contact with mosquitoes and cause the greatest mortality might be additionally used in assessing the effectiveness of interventions.…”

“…Various high-tech techniques, such as high performance liquid chromatography (HPLC) and gas chromatography (GC) are often used for measuring the amounts of pyrethroids but are reliant on sophisticated laboratory-based equipment and need both expertise and experience to utilize [26,27,28]. More recently, colorimetric tests have been developed and used for detection of pyrethroids [29,30,31,32] and carbamates [33], as well as biosensors using glutathione-S-transferase for pyrethroids [34,35,36] and DDT [37], and DDT dipstick assays [38] on fabrics and IRS. To date these methods have not been used to detect insecticides on exposed mosquitoes.…”