Efficacy of broflanilide (VECTRON™ T500), a new meta-diamide insecticide, for indoor residual spraying against pyrethroid-resistant malaria vectors

Ngufor, Corine; Govoétchan, Renaud; Fongnikin, Augustin; Vigninou, Estelle; Syme, Thomas; Akogbéto, Martin; Rowland, Mark

doi:10.1101/2020.11.06.367961

Cited by 4 publications

(4 citation statements)

References 30 publications

(44 reference statements)

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“…This will suggest a lack of correlation between the efficacy of Pirikool® 300CS on cement substrates in laboratory bioassays compared to experimental hut studies demonstrating longer residual efficacy with the latter compared to the former. This lack of correlation between laboratory cone bioassays and experimental hut in situ wall cone bioassays on cement substrates was also observed in studies involving another IRS insecticide under development [ 26 ]. Although the cement block substrates and cement wall plaster of the experimental huts were prepared using the same cement-sand ratio, there may be some differences in porosity or texture which could have contributed to the differences in residual efficacy of Pirikool® 300CS in both studies.…”

Section: Discussionmentioning

confidence: 73%

Pirikool® 300 CS, a new long-lasting capsule suspension formulation of the organophosphate insecticide pirimiphos-methyl for indoor residual spraying against pyrethroid-resistant malaria vectors

Fongnikin¹,

Odjo²,

Akpi³

et al. 2022

PLoS ONE

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Background Indoor residual spraying (IRS) using a capsule suspension formulation of the organophosphate insecticide, pirimiphos-methyl, has provided substantial malaria control in many communities in Africa. However, only one brand of this product has been recommended by the World Health Organisation for IRS. To help increase the diversity of the portfolio of IRS insecticides and offer suitable options to procurers and malaria vector control programmes, additional product brands of this highly effective and long-lasting insecticide formulation for IRS will be needed. Methods We evaluated the efficacy of Pirikool® 300CS, a new capsule suspension formulation of pirimiphos-methyl developed by Tianjin Yorkool, International Trading, Co., Ltd in standard WHO laboratory bioassays and experimental hut studies. The efficacy of the insecticide applied at 1000mg/m2 was assessed in laboratory bioassays for 6 months on cement, plywood and mud block substrates and for 12 months in cement and mud-walled experimental huts against wild free-flying pyrethroid-resistant Anopheles gambiae sensu lato in Covè, Benin. Actellic® 300CS, a WHO-recommended capsule suspension formulation of pirimiphos-methyl was also tested. WHO cylinder tests were performed to determine the frequency of insecticide resistance in the wild vector population during the hut trial. Results The vector population at the hut station was resistant to pyrethroids but susceptible to pirimiphos-methyl. Overall mortality rates of wild free-flying pyrethroid-resistant An. gambiae (s.l.) entering Pirikool®300CS treated experimental huts during the 12-month trial were 86.7% in cement-walled huts and 88% in mud-walled huts. Mortality of susceptible An. gambiae (Kisumu) and pyrethroid-resistant An. gambiae s.l. (Covè) mosquitoes in monthly wall cone bioassays on Pirikool® 300CS treated hut walls remained over 80% for 10–12 months. The laboratory bioassays corroborated the hut findings with Pirikool® 300CS on mud and wood block substrates but not on cement block substrates. Conclusion Indoor residual spraying with Pirikool® 300CS induced high and prolonged mortality of wild pyrethroid-resistant malaria vectors for 10–12 months. Addition of Pirikool®300CS to the current portfolio of IRS insecticides will provide an extra choice of microencapsulated pirimiphos-methyl for IRS.

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Section: Discussionmentioning

confidence: 73%

Pirikool® 300 CS, a new long-lasting capsule suspension formulation of the organophosphate insecticide pirimiphos-methyl for indoor residual spraying against pyrethroid-resistant malaria vectors

Fongnikin¹,

Odjo²,

Akpi³

et al. 2022

PLoS ONE

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“…colluzi and ~ 55% An. gambiae ss and is highly resistant to pyrethroids with high levels of kdr (> 80%) and overexpressed P450 enzymes [19].…”

Section: Study Areamentioning

confidence: 99%

Mosquito ShieldTM, a transfluthrin passive emanator, protects against pyrethroid-resistant Anopheles gambiae s.l in central Benin

Fongnikin,

Ahoga,

Ndombidje

et al. 2024

Preprint

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Background: Spatial repellents can provide personal and household protection against biting vector mosquitoes by volatising repellents into the air within a given area. Mosquito ShieldTM is a transfluthrin passive emanator undergoing evaluation for malaria control. Studies evaluating its entomological impact against different local malaria vector populations would help guide its deployment in endemic countries. Methods: We performed a two-arm single-blinded small-scale household randomised entomological trial to assess the impact of Mosquito ShieldTM on the human landing rate of wild pyrethroid-resistant Anopheles gambiae sl vector mosquitoes in houses in the Ganhoua village of the Zakpota District of central Benin. From a total of 30 houses, 15 were randomly allocated to receive Mosquito ShieldTM while the remainder received a placebo product. The trial lasted through the life of the Mosquito ShieldTM product (32 days). Mosquito sampling was performed by human landing catches at baseline and at 6 timepoints post-intervention (days 0-1, 7-8, 14-15, 21-22, 28-29 and 31-32). Collections were performed for 2 days at each sampling time point. WHO cylinder bioassays were conducted during the trial with F1, An gambiae sl mosquitoes that emerged from larvae from the study area to assess the intensity of resistance to pyrethroids in the wild vector population. Findings: The vector population in the study area showed a high intensity of resistance to pyrethroids. Baseline An gambiae sl human landing rates were similar in houses in both study arms before product application (11.53/person/night vs 11.67/person/night, p>0.05). A total of 5736 mosquitoes were collected in the placebo control arm and 3862 in the Mosquito ShieldTM arm post-intervention. Overall An gambiae sl human landing rates post-intervention were significantly lower in houses in the Mosquito ShieldTM arm 18.13/person/night) compared to the houses in the placebo control arm (26.84/person/night, IRR=0.658, p<0.001). Over the lifespan of the product, Mosquito ShieldTM provided a significant protective efficacy of 34.2% (22.1%-44.4%, p<0.001) against wild pyrethroid-resistant An gambiae s.l. vectors compared to the placebo. Human landing rates of other nuisance vector mosquito species (Culex and Mansonia) were also reduced in houses treated with Mosquito ShieldTM compared to the placebo. Conclusion: Mosquito ShieldTM, a transfluthrin passive emanator, provided significant protection against pyrethroid-resistant malaria vectors to households in Benin. The spatial repellent shows potential to reduce malaria transmission by pyrethroid-resistant An gambiae sl vector mosquitoes and cover gaps in malaria control when deployed to complement existing vector control interventions.

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“…Such data might also be useful for decision-making for the deployment of appropriate contextspeci c vector control interventions. The present study was conducted in the Za-Kpota sub-district of central Benin to collect baseline data on malaria prevalence, vector characteristics and transmission dynamics in preparation for a randomised controlled trial to evaluate the community impact of VECTRON™ T500, a new bro anilide insecticide product for IRS [31].…”

Section: Introductionmentioning

confidence: 99%

Malaria prevalence and transmission in the Zakpota sub-district of central Benin: baseline characteristics for a community randomised trial of a new insecticide for indoor residual spraying

Govoetchan,

Fongnikin,

Hueha

et al. 2024

Preprint

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Introduction: Malaria transmission is known to be perennial and heterogeneous in Benin. Studies assessing local malaria prevalence, transmission levels and vector characteristics are critical for designing, monitoring and evaluating new vector control interventions in community trials. We conducted a study in the Zakpota sub-district of central Benin to collect baseline data on household characteristics, malaria prevalence, vector characteristics and transmission dynamics in preparation for a randomised controlled trial to evaluate the community impact of VECTRON™ T500, a new broflanilide indoor residual spraying (IRS) product. Method A total of 480 children under 5 years of age from the 15 villages of the sub-district were tested for malaria by rapid diagnostic tests (RDTs). Mosquitoes were collected by human landing catches (HLCs), pyrethrum spray catches (PSCs) and Centers for Disease Control miniature light traps (CDC-LTs) in selected houses in each village to assess vector density, composition, vector infectivity and prevalence insecticide resistance markers. Bioassays were performed to detect vector susceptibility to pyrethroids, broflanilide (6µg/bottle) and clothianidin (90µg /bottle). Results A total of 9,080 households were enumerated in the 15 study villages. Insecticide-treated net (ITN) usage was > 90% with 1–2 ITNs owned per household. Houses were constructed mainly with cement (44%) and mud (38%) substrates or a mixture of cement and mud (18%) and 60% of them had open eaves. The overall prevalence of P. falciparum infection was 19% among surveyed children; 20% among females and 18% among males. The haemoglobin rate showed an anaemia (< 11 g/dL) prevalence of 66%. An. coluzzii and An. gambiae s.s. were the two vector species present at an overall proportion of 46% vs. 54% respectively. The human biting rate was 2.3 bites per person per night (b/p/n) and biting occurred mostly indoors compared to outdoors (IRR = 0.776; p = 0.001). The overall proportion of outdoor biting was 44% and exceeded indoor biting in 3 villages. The sporozoite rate was 2% with a combined monthly entomological inoculation rate (EIR) of 16.1 infected bites per person per year (ib/p/y). There was great variability in malaria transmission risk across the villages with EIR ranging from 0-29.3 ib/p/y. The vector population showed a high intensity of resistance to pyrethroids across the study villages but was largely susceptible to broflanilide and clothianidin. Conclusion This study found high levels of malaria prevalence, vector density and transmission in the Zakpota sub-district despite the high use of insecticide-treated nets. The vector population was mostly indoor resting and showed a high intensity of pyrethroid resistance but was generally fully susceptible to broflanilide. These findings demonstrated the suitability of the study area for the assessment of VECTRON™ T500 in a community randomised trial.

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Efficacy of broflanilide (VECTRON™ T500), a new meta-diamide insecticide, for indoor residual spraying against pyrethroid-resistant malaria vectors

Cited by 4 publications

References 30 publications

Pirikool® 300 CS, a new long-lasting capsule suspension formulation of the organophosphate insecticide pirimiphos-methyl for indoor residual spraying against pyrethroid-resistant malaria vectors

Pirikool® 300 CS, a new long-lasting capsule suspension formulation of the organophosphate insecticide pirimiphos-methyl for indoor residual spraying against pyrethroid-resistant malaria vectors

Mosquito ShieldTM, a transfluthrin passive emanator, protects against pyrethroid-resistant Anopheles gambiae s.l in central Benin

Malaria prevalence and transmission in the Zakpota sub-district of central Benin: baseline characteristics for a community randomised trial of a new insecticide for indoor residual spraying

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