Development and optimization of the Suna trap as a tool for mosquito monitoring and control

Abstract

BackgroundMonitoring of malaria vector populations provides information about disease transmission risk, as well as measures of the effectiveness of vector control. The Suna trap is introduced and evaluated with regard to its potential as a new, standardized, odour-baited tool for mosquito monitoring and control.MethodsDual-choice experiments with female Anopheles gambiae sensu lato in a laboratory room and semi-field enclosure, were used to compare catch rates of odour-baited Suna traps and MM-X traps. The relative performance of the Suna trap, CDC light trap and MM-X trap as monitoring tools was assessed inside a human-occupied experimental hut in a semi-field enclosure. Use of the Suna trap as a tool to prevent mosquito house entry was also evaluated in the semi-field enclosure. The optimal hanging height of Suna traps was determined by placing traps at heights ranging from 15 to 105 cm above ground outside houses in western Kenya.ResultsIn the laboratory the mean proportion of An. gambiae s.l. caught in the Suna trap was 3.2 times greater than the MM-X trap (P < 0.001), but the traps performed equally in semi-field conditions (P = 0.615). As a monitoring tool , the Suna trap outperformed an unlit CDC light trap (P < 0.001), but trap performance was equal when the CDC light trap was illuminated (P = 0.127). Suspending a Suna trap outside an experimental hut reduced entry rates by 32.8% (P < 0.001). Under field conditions, suspending the trap at 30 cm above ground resulted in the greatest catch sizes (mean 25.8 An. gambiae s.l. per trap night).ConclusionsThe performance of the Suna trap equals that of the CDC light trap and MM-X trap when used to sample An. gambiae inside a human-occupied house under semi-field conditions. The trap is effective in sampling mosquitoes outside houses in the field, and the use of a synthetic blend of attractants negates the requirement of a human bait. Hanging a Suna trap outside a house can reduce An. gambiae house entry and its use as a novel tool for reducing malaria transmission risk will be evaluated in peri-domestic settings in sub-Saharan Africa.

Eave Screening and Push-Pull Tactics to Reduce House Entry by Vectors of Malaria

“…33 It was baited with an attractive five-compound odor blend released from nylon strips, 28,30 augmented with carbon dioxide (CO 2 ) produced by the fermentation of molasses. 38 Fresh odor baits were provided at the start of the experiment and left in place throughout the entire trial as previous studies have shown that the strips remain attractive for at least 52 nights after impregnation.…”

“…The Suna trap was hung outside the house, next to the door, suspended from the overhanging roof with a nylon line, with the air inlet positioned at 30 cm above ground level. 33 Field experiment II. In the second field experiment, conducted in October and November 2014, cotton net fabric was used for eave screening instead of wire mesh.…”

“…[29][30][31] An ongoing large-scale intervention study explores the potential of mass-trapping malaria vectors to reduce malaria transmission on an island community in western Kenya. 32 By actively removing mosquitoes from the peridomestic environment, attractant-baited traps can provide a dual-protective effect: 1) a direct effect by reducing house entry of mosquitoes that would otherwise have entered 16,33 and 2) an indirect effect by reducing the average mosquito's life span and by depleting mosquito populations through daily removal trapping. 34,35 A pilot experiment in which a human-occupied house in a semifield setup was fully screened (eaves and other openings) and equipped with an attractant-baited trap hanging outside the house indicated that this approach could dramatically reduce house entry of malaria vectors and enhance attractant-baited trap catches.…”

Combining malaria control with rural electrification : social and behavioural factors that influenced the design, use and sustainability of solar-powered mosquito trapping systems (SMoTS) for malaria elimination on Rusinga Island, western Kenya

“…Trapped mosquitoes cannot escape and they eventually die due to lack of water and food. The Suna trap has been described elsewhere (Hiscox, Otieno et al 2014). Figure 6 shows a cross-sectional diagram of a Suna trap.…”

“…Because the 5-component odour bait and carbon dioxide mimic was expected to attract and remove a constant fraction of the malaria vector each day, it was considered that the continuous presence of the odour-baited traps was more important in controlling malaria than maximum daily efficacy. The new odour combination was released from small nylon strips suspended inside the cone of the Suna trap (Hiscox, Otieno et al 2014). …”