Experimental huts trial of the efficacy of pyrethroids/piperonyl butoxide (PBO) net treatments for controlling multi-resistant populations of Anopheles funestus s.s. in Kpomè, Southern Benin

Akoton, Romaric; Tchigossou, Genevieve M.; Djègbè, Innocent; Yessoufou, Akadiri; Atoyebi, Seun M.; Tossou, Eric; Zeukeng, Francis; Boko, Pélagie; Irving, Helen; Adéoti, Razack; Riveron, Jacob M.; Wondji, Charles S.; Moutaïrou, Kabirou; Djouaka, Rousseau

doi:10.12688/wellcomeopenres.14589.1

Cited by 18 publications

(20 citation statements)

References 55 publications

(89 reference statements)

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“…To mitigate the negative impacts of higher levels of insecticide resistance, a new generation of mosquito insecticide-treated nets (ITNs) has been developed with a combination of pyrethroids and a synergist, piperonyl butoxide (PBO). Some studies have found PBO effective in increasing mortality in resistant mosquitoes in southern Benin [ 14 , 24 , 25 ]. However, additional studies in different locations or in different years are still useful to better characterize the spatial and temporal landscape of resistance occurrence.…”

Section: Introductionmentioning

confidence: 99%

Intensity and mechanisms of deltamethrin and permethrin resistance in Anopheles gambiae s.l. populations in southern Benin

Sagbohan¹,

Kpanou²,

Ossè³

et al. 2021

Parasites Vectors

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Background Insecticide resistance is threatening the effectiveness of efforts to control malaria vectors in Benin. This study explores the levels and mechanisms of insecticide resistance in An. gambiae s.l. to pyrethroids. Methods Larvae were collected from August 2017 to July 2018 in five communes in southern Benin (Adjohoun, Allada, Bohicon, Cotonou, and Porto-Novo) representing diverse ecological regions, and were reared in Benin’s insectary. Two- to five-day-old female mosquitoes from each district were exposed to multiple doses of deltamethrin and permethrin (1×, 2×, 5×, and 10×) using the WHO insecticide resistance intensity bioassay. The effect of pre-exposure to the synergist, piperonyl butoxide (PBO), was also tested at different pyrethroid doses. Molecular allele frequencies of kdr (1014F) and ace-1R (119S) insecticide resistance mutations and levels of detoxification enzymes were determined for mosquitoes sampled from each study area. Results An. gambiae s.l. were resistant to pyrethroid-only exposure up to 10× the diagnostic doses in all the study sites for both deltamethrin and permethrin. Mortality was significantly higher in An. gambiae s.l. pre-exposed to PBO followed by exposure to deltamethrin or permethrin compared to mosquitoes exposed to deltamethrin or permethrin only (p < 0.001). The difference in mortality between deltamethrin only and PBO plus deltamethrin was the smallest in Cotonou (16–64%) and the greatest in Bohicon (12–93%). The mortality difference between permethrin only and PBO plus permethrin was the smallest in Cotonou (44–75%) and the greatest in Bohicon (22–72%). In all the study sites, the kdr resistance allele (1014F) frequency was high (75–100%), while the ace-1 resistance allele (G119S) frequency was low (0–3%). Analysis of the metabolic enzymatic activity of An. gambiae s.l. showed overexpression of nonspecific esterases and glutathione S-transferases (GST) in all study sites. In contrast to the PBO results, oxidase expression was low and was similar to the susceptible An. gambiae s.s. Kisumu strain in all sites. Conclusion There is high-intensity resistance to pyrethroids in southern Benin. However, pre-exposure to PBO significantly increased susceptibility to the pyrethroids in the different An. gambiae s.l. populations sampled. The use of PBO insecticide-treated bed nets may help maintain the gains in An. gambiae (s.l.) control in southern Benin. Graphical Abstract

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Section: Introductionmentioning

confidence: 99%

Intensity and mechanisms of deltamethrin and permethrin resistance in Anopheles gambiae s.l. populations in southern Benin

Sagbohan¹,

Kpanou²,

Ossè³

et al. 2021

Parasites Vectors

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“…In a bid to ensure the success of malaria control strategies, studies have been conducted on different approaches to managing resistance development. Several evidences had supported the use of Piperonyl Butoxide incorporation with pyrethroids to eliminate detoxifying enzymes mediated resistance to pyrethroid on mosquito population [9].…”

Section: Introductionmentioning

confidence: 99%

Evidence of Metabolic Resistance in Pyrethroid Resistant Aedes aegypti Population from Lagos, Nigeria

2020

PAJOLS

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Background: Pyrethroid resistance in Aedes aegypti is of major concern to the control of several arboviral infections. The major mechanisms of Pyrethroid resistance in mosquitoes are target-site insensitivity and elevation in the activity of detoxification enzymes. In this study, we assessed the susceptibility status of Aedes aegypti population from Lagos to Pyrethroid and the impact of metabolic enzymes on resistance development. Methods: Larvae of Aedes aegypti were collected from differ ent habitats in Lagos Mainland Local Government Area, Lagos state. Adult mosquitoes of 2-5 days were exposed to diagnostic dose of permethrin and Deltamethrin using the CDC method. Synergist assay was done with pre-exposure of samples to PBO before exposure to insecticide. Esterase and GST activities were measured using standard protocol. Regression Probit was used to compute the KDT50 and KDT95. Analysis of variance was used to compare the difference in mean of enzymes activities. Results: Aedes aegypti population from the study location is resistant to permethrin (33% ) and Deltamethrin (80%) within the diagnostic time. PBO pre-exposure increases percentage knockdown from 33% to 82% and 80% to 87% for permethrin and Deltamethrin respectively. The activity of GST was higher (P<0.05) in permethrin exposed mosquitoes in comparison with unexposed. Conclusion: A robust insecticide resistance management (IRM) plan in Lagos should take into consideration strategies for addressing the effects of metabolic enzymes in resistance development .

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“…gambiae and Culex quinquefasciatus in Benin [22]. Another study conducted in Southern Benin showed that the combined permethrin-PBO net was not a solution to control the pyrethroid-resistant Anopheles coluzzii [23]. Therefore, pyrethroid-PBO mixture nets could not always be a promising strategy against pyrethroid-resistant malaria vector populations.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of DawaPlus 3.0 and DawaPlus 4.0, deltamethrin–PBO combination nets against pyrethroid-resistant Anopheles culicifacies in experimental huts in India

Gunasekaran

Vijayakumar

Subramanian

et al. 2020

Malar J

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Background: The development of resistance in vectors is one of the major impediments for malaria control. Adding synergists to insecticides has proven to be an alternative choice for controlling resistant mosquitoes. DawaPlus 3.0 and DawaPlus 4.0 are new long-lasting insecticidal nets (LLINs) in which deltamethrin and a synergist, piperonyl butoxide (PBO) are added into filaments and their efficacy was tested against resistant malaria vector, Anopheles culicifacies in experimental huts in India. Methods: The performance of two trial nets in terms of deterrence induced exiting, blood-feeding inhibition and mortality of An. culicifacies was compared with DawaPlus 2.0 and untreated net. Results: There was a significant reduction in entry, blood feeding and mortality (p < 0.05) and increase in exit rates of An. culicifacies in the treatment arms compared to untreated arm. But, both candidate LNs washed 20 times could not perform better than the washed reference net (DawaPlus 2.0). Cone bioassay results showed that all the treatment arms (both washed and unwashed) produced < 80% mortality of An. culicifacies before and after hut evaluation. Conclusions: DawaPlus 3.0 and DawaPlus 4.0 with their current specification may not be as effective as required to control the resistant vector, An. culicifacies, in east-central India.

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Experimental huts trial of the efficacy of pyrethroids/piperonyl butoxide (PBO) net treatments for controlling multi-resistant populations of Anopheles funestus s.s. in Kpomè, Southern Benin

Cited by 18 publications

References 55 publications

Intensity and mechanisms of deltamethrin and permethrin resistance in Anopheles gambiae s.l. populations in southern Benin

Intensity and mechanisms of deltamethrin and permethrin resistance in Anopheles gambiae s.l. populations in southern Benin

Evidence of Metabolic Resistance in Pyrethroid Resistant Aedes aegypti Population from Lagos, Nigeria

Evaluation of DawaPlus 3.0 and DawaPlus 4.0, deltamethrin–PBO combination nets against pyrethroid-resistant Anopheles culicifacies in experimental huts in India

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