A Chlorfenapyr Mixture Net Interceptor® G2 Shows High Efficacy and Wash Durability Against Resistant Mosquitoes in West Africa

Overview

Journal PLoS One

Specialties General Medicine
Science

Date 2016 Nov 17

PMID 27851828

Citations 64

Authors

Raphael NGuessan

Abibatou Odjo

Corine Ngufor

David Malone

Mark Rowland

Affiliations

Soon will be listed here.

Abstract

Background: Malaria control through use of long-lasting insecticidal nets (LN) is threatened by the selection of anopheline mosquitoes strongly resistant to pyrethroid insecticides. To sustain future effectiveness it is essential to identify and evaluate novel insecticides suitable for nets. Mixtures of two insecticides with contrasting mode of action have the potential to kill resistant vectors and restore transmission control provided the formulation can withstand regular washing over the net's life span.

Method: The efficacy of a novel mixture LN, Interceptor® G2, that combines the pyrrole chlorfenapyr and pyrethroid alpha-cypermethrin was evaluated under controlled household conditions (experimental hut trial) and by laboratory bioassay against pyrethroid resistant An. gambiae in Benin before and after standardized washing. Comparison arms included standard alpha-cypermethrin LN, nets hand-treated with chlorfenapyr-only and untreated nets.

Results: The chlorfenapyr-alphacypermethrin LN demonstrated improved efficacy and wash resistance compared to a standard alpha-cypermethrin LN against pyrethroid resistant mosquitoes (resistance ratio 207). In experimental hut trial alpha-cypermethrin LN killed only 20% (95% CI 15-26%) of host-seeking An. gambiae whilst mixture LN killed 71% (95% CI 65-77%). Mixture LN washed 20 times killed 65% (95% CI 58-71%), and thus intensive washing reduced efficacy by only 6% (95% CI 1.3-11%). The chlorfenapyr net killed 76% (95% CI 70-81%). Personal protection and blood feeding inhibition did not differ between mixture and pyrethroid LN; however, the mixture LN was 2.5 (95% CI: 2.1-3.1) times more protective than untreated nets. Standard WHO cone bioassays conducted during day time hours failed to anticipate field efficacy but overnight tunnel tests successfully predicted mixture LN and chlorfenapyr net efficacy in field trials.

Conclusion: Interceptor® G2 LN demonstrates the potential to control transmission and provide community protection over the normal lifespan of long lasting nets where standard pyrethroid LN show signs of failing due to resistance.

Citing Articles

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Efficacy of PermaNet Dual compared to Interceptor G2 and PermaNet 3.0 in experimental huts in Siaya County, western Kenya.

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Laboratory evaluation of the regeneration time, efficacy and wash-resistance of PermaNet Dual (a deltamethrin-chlorfenapyr net) against susceptible and pyrethroid-resistant strains of Anopheles gambiae sensu lato.

Syme T, Ndombidje B, Todjinou D, Ariori V, Ngufor C PLoS One. 2024; 19(8):e0298513.

PMID: 39208123 PMC: 11361417. DOI: 10.1371/journal.pone.0298513.

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