The development of an ivermectin-based attractive toxic sugar bait (ATSB) to target Anopheles arabiensis

Abstract

BackgroundAn increasing number of countries in sub-Saharan Africa are moving towards malaria-elimination, mostly thanks to successful vector control campaigns. However, elimination has proven challenging, resulting in the persistence of malaria transmission. It is now accepted that in order to eliminate malaria, new complementary vector control approaches must be developed. This study describes the development of a sugar-baited resting place containing a toxic dose of ivermectin for the control of Anopheles arabiensis.ResultsDose response experiments were performed in insectary conditions to determine the LD90 of ivermectin against An. arabiensis. Over 95% of An. arabiensis were knocked down 48 h post-sugar feeding on 10% sucrose solutions containing 0.01% ivermectin. When investigating different juices as attractants, it was observed that An. arabiensis preferred orange, watermelon and commercial guava juice over pawpaw, tomato, mango or banana, but were most likely to feed on simple 10% sugar solution. Using recycled materials, different bait prototypes were tested to determine the best design to maximize sugar feeding. Baits that offered a resting place for the mosquito rather than just a surface to sugar feed were more likely to attract An. arabiensis to sugar feed. The optimized prototype was then placed in different locations within a screen-house, colour-coded with different food dyes, containing competing vegetation (Ricinus communis) and experimental huts where humans slept under bed nets. Around half of all the released An. arabiensis sugar fed on the sugar baits, and approximately 50% of all sugar fed mosquitoes chose the baits close to outdoor vegetation before entering the huts.ConclusionsIvermectin is an effective insecticide for use in sugar baits. The design of the sugar bait can influence feeding rates and, therefore, efficacy. Sugar baits that offer a resting surface are more efficient and sugar feeding on the baits is maximized when these are placed close to peri-domestic vegetation. Attractive toxic sugar baited resting places may provide an additional vector control method to complement with existing strategies.

Behavioural and Electrophysiological Responses of Female Anopheles gambiae Mosquitoes to Volatiles from a Mango Bait

“…gambiae, show are attracted to certain plants (Gouagna et al 2010;Manda et al 2007;Mauer and Rowley 1999;Müller et al 2011). In addition to other plant parts such as flowers and leaves, female mosquitoes showed an obvious attraction to the odors of fruits (Hien et al 2016;Müller et al 2011;Yu et al 2017) and fruit juices (Tenywa et al 2017). This is consistent with our results as An.…”

“…Recently, attractants from fruit juice were used to lure mosquitoes to an insecticide as a development of ATSB (Beier et al 2012). Tenywa et al (2017) reported that Anopheles spp. mosquitoes were attracted to juice from subtropical fruits such as guava, mango and banana.…”

Controlling mosquitoes with semiochemicals: a review

“…Current commercial traps are expensive and bulky as they require a CO 2 source and usually contain foul smelling synergists. Alternative traps made from recycled materials [108], such as buckets (for example the Gravid Aedes Trap) [109] and sticky traps, using products available in the home, such as castor oil [110], need further investigation as these can provide a low-cost and practical solution for vector control in developing countries. The focus of most of the research has primarily been on single olfactory compounds or blends containing less than five compounds.…”

Attractive toxic sugar baits for controlling mosquitoes: a qualitative study in Bagamoyo, Tanzania

“…An attractive-toxic sugar bait was developed and tested inside a biodome at the Ifakara Health Institute [ 11 ]. The prototype tested in the semi-field demonstrated an ability to attract at least 50% of the free flying Anopheles arabiensis and that these were most likely to choose to feed on a sugar bait placed outdoors amidst vegetation although it would also feed indoors if humans were protected by a bed net [ 11 ]. The ATSBs that were distributed contained 0.01% ivermectin in 10% sugar solution, and its structure was made using 100% recycled materials readily available in rural Tanzania (Fig.…”