Trapping and killing performance of a PermaNet 2.0 hybrid trapping bednet : an experimental hut evaluation.

Background: There is an increase in malaria morbidity and mortality in sub-Saharan Africa since 2015, from 212 million cases and 429 000 deaths in 2015 to 241 million cases and 627 000 deaths in 2020 mainly because of resistance to insecticide used in malaria vector control tools. Consequently, failure to mitigate this phenomenon can result in an even more increase of disease burden, potentially reversing some of the substantial gains made in controlling malaria over the last decade. Therefore, advancing innovative approaches is the only sustainable way to fight malaria.

Methods: Taking advantage of the behavior of mosquitoes around the net, which is almost 70-90% concentrated on the roof, we have developed a two-compartment mosquito bednet, the so-called T-Net for mass mosquito trapping and killing. In the current study, we investigated in an experimental hut trial, the efficacy of trapping-LLINs (T-LLINs) against Anopheles gambiae s.l. in a insecticide resistance context. Five different arms have been considered in this study including three positive control arms e.g. PermaNet 2.0 LLIN, Tsara boost LLIN and Interceptor generation 2 (IG2) LLIN), one negative control arm using insecticide-free bednet, and one candidate arm using a hybrid-treated T-Net made with PermaNet 2.0 LLIN mounted with an insecticide-free compartment (T-LLIN).

Results: The highest average daily mortality was recorded with the T-LLIN. In total, 678 mosquitoes were killed by T-LLIN among the 760 collected, i.e. 89.2%. Out of these, 317 were found in the trap compartment, representing 46.75% of mortality directly attributable to the mechanical effect of this net. This added value made it possible to quantify the increased in the killing effect that this net would have over the positive control arms: this would be 52% higher than the killing effect of PN2.0, 25.2% higher than that of Tsara boost and 23% higher than that of IG2.

Conclusion: The current study shows potential to maximize the efficiency of the WHO-recommended LLINs by an addition of an insecticide-free trap compartment on top of the net.