A multi-country non-inferiority experimental hut evaluation of DuraNet® Plus, an alpha-cypermethrin and piperonyl butoxide treated net, for control of pyrethroid-resistant malaria vectors in West and Central Africa

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Abstract Background Pyrethroid-piperonyl butoxide (PBO) nets enhance malaria vector control by counteracting metabolic resistance mechanisms in malaria vectors through the synergistic action of PBO. DuraNet® Plus is an alpha-cypermethrin and PBO incorporated net developed Shobikaa Impex Private Limited. This study assessed its entomological efficacy relative to a standard pyrethroid-only net (DuraNet®) and an established pyrethroid-PBO net (Olyset® Plus), in support of WHO prequalification. Methods Experimental hut trials were conducted at three ecologically and entomologically distinct sites with pyrethroid-resistant vector populations: Covè, Benin ( Anopheles gambiae s.l.), Mibellon, Cameroon ( An. funestus ), and M’bé, Côte d’Ivoire ( An. gambiae s.l.). Each net type was tested unwashed and after 20 standardized washes. Primary outcomes included 24-hour mosquito mortality and blood-feeding inhibition. DuraNet® Plus was evaluated for non-inferiority to Olyset® Plus and superiority over DuraNet® using combined washed and unwashed data, in line with WHO guidelines. WHO bioassays confirmed pyrethroid resistance and assessed the role of cytochrome P450 enzymes. Chemical analyses measured pyrethroid and PBO retention after washing. Results DuraNet® Plus consistently induced higher mosquito mortality than Olyset® Plus across all sites (Benin: 29.5% vs. 14.9%, OR = 2.81, 95% CI: 2.34–3.38, NIM = 0.468; Cameroon: 27.8% vs. 22.2%, OR = 1.81, 95% CI: 1.32–2.49, NIM = 0.619; Côte d’Ivoire: 19.5% vs. 12.0%, OR = 2.28, 95% CI: 1.85–2.80, NIM = 0.373), with all odds ratios exceeding the WHO-defined non-inferiority margins. DuraNet® Plus also met non-inferiority criteria for blood-feeding inhibition compared to Olyset® Plus (Benin: OR = 0.23, 95% CI: 0.18–0.28, NIM = 1.345; Cameroon: OR = 0.66, 95% CI: 0.50–0.87, NIM = 1.324; Côte d’Ivoire: OR = 0.58, 95% CI: 0.48–0.69, NIM = 1.404). In addition, DuraNet® Plus was superior to DuraNet® in both mosquito mortality and blood-feeding inhibition across all study sites (p < 0.05). Susceptibility bioassays confirmed high frequencies of pyrethroid resistance across all three sites, with varying levels of P450 enzyme involvement. Chemical analysis showed higher retention of alpha-cypermethrin and PBO in DuraNet® Plus after 20 washes compared to Olyset® Plus. Conclusion DuraNet® Plus showed strong entomological efficacy and wash durability against pyrethroid-resistant malaria vectors across varied settings in West and Central Africa. It met WHO non-inferiority criteria compared to Olyset® Plus and was superior to a pyrethroid-only ITN, supporting its inclusion among WHO-prequalified products. These findings underscore its potential role in vector control strategies in areas affected by metabolic pyrethroid resistance.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.