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Overcoming insecticide resistance in Anopheles mosquitoes by using faster-acting solid forms of deltamethrin

Authors :
Jessica Carson
Bryan Erriah
Stephania Herodotou
Alexander G. Shtukenberg
Leilani Smith
Svetlana Ryazanskaya
Michael D. Ward
Bart Kahr
Rosemary Susan Lees
Source :
Malaria Journal, Vol 22, Iss 1, Pp 1-8 (2023)
Publication Year :
2023
Publisher :
BMC, 2023.

Abstract

Abstract Background Controlling malaria-transmitting Anopheles mosquitoes with pyrethroid insecticides is becoming increasingly challenging because of widespread resistance amongst vector populations. The development of new insecticides and insecticidal formulations is time consuming and costly, however. A more active crystalline form of deltamethrin, prepared by heating the commercial crystalline form, previously was reported to be 12-times faster acting against susceptible North American Anopheles quadrimaculatus mosquitoes. Herein the potential for heat-activated deltamethrin dispersed on chalk to overcome various resistance mechanisms amongst five West African Anopheles strains is investigated, and its long-term sustained lethality evaluated. Methods The more active deltamethrin form was generated in a commercial dust containing deltamethrin by heating the material as purchased. Tarsal contact bioassays were conducted to investigate its efficacy, potency, and speed of action against resistant Anopheles populations compared to the commercially available form of deltamethrin dust. Results In all cases, D-Fense Dust heated to generate the more active form of deltamethrin was substantially more effective than the commercially available formulation. 100% of both Banfora M and Kisumu populations were knocked down 10 min post-exposure with no recovery afterwards. Gaoua-ara and Tiefora strains exhibited 100% knockdown within 15 min, and the VK7 2014 strain exhibited 100% knockdown within 20 min. In all cases, 100% mortality was observed 24 h post-exposure. Conversely, the commercial formulation (unheated) resulted in less than 4% mortality amongst VK7 2014, Banfora, and Gaoua-ara populations by 24 h, and Tiefora and Kisumu mosquitoes experienced 14 and 47% mortality by 24 h, respectively. The heat-activated dust maintained comparable efficacy 13 months after heating. Conclusions The heat-activated form of commercial deltamethrin D-Fense Dust outperformed the material as purchased, dramatically increasing efficacy against all tested pyrethroid-resistant strains. This increase in lethality was retained for 13 months of storage under ambient conditions in the laboratory. Higher energy forms of commonly used insecticides may be employed to overcome various resistance mechanisms seen in African Anopheles mosquitoes through more rapid uptake of insecticide molecules from their respective solid surfaces. That is, resistant mosquitoes can be killed with an insecticide to which they are resistant without altering the molecular composition of the insecticide.

Details

Language :
English
ISSN :
14752875
Volume :
22
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Malaria Journal
Publication Type :
Academic Journal
Accession number :
edsdoj.9aade4465744197b310ddcb37b82f17
Document Type :
article
Full Text :
https://doi.org/10.1186/s12936-023-04554-x