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  1. Article ; Online: Laboratory evaluation of the contact irritancy of a clothianidin solo formulation vs. clothianidin-deltamethrin mixture formulations for indoor residual spraying against pyrethroid-resistant Anopheles gambiae sensu lato.

    Syme, Thomas / N'dombidjé, Boris / Odjo, Aicha / Gbegbo, Martial / Todjinou, Damien / Ngufor, Corine

    Parasites & vectors

    2024  Volume 17, Issue 1, Page(s) 183

    Abstract: Background: Clothianidin-based indoor residual spraying (IRS) formulations have become available for malaria control as either solo formulations of clothianidin or a mixture of clothianidin with the pyrethroid deltamethrin. While both formulations have ... ...

    Abstract Background: Clothianidin-based indoor residual spraying (IRS) formulations have become available for malaria control as either solo formulations of clothianidin or a mixture of clothianidin with the pyrethroid deltamethrin. While both formulations have been successfully used for malaria control, studies investigating the effect of the pyrethroid in IRS mixtures may help improve our understanding for development of future IRS products. It has been speculated that the irritant effect of the pyrethroid in the mixture formulation may result in shorter mosquito contact times with the treated walls potentially leading to a lower impact.
    Methods: We compared contact irritancy expressed as the number of mosquito take-offs from cement surfaces treated with an IRS formulation containing clothianidin alone (SumiShield® 50WG) to clothianidin-deltamethrin mixture IRS formulations against pyrethroid-resistant Anopheles gambiae sensu lato under controlled laboratory conditions using a modified version of the World Health Organisation cone bioassay. To control for the pyrethroid, comparison was made with a deltamethrin-only formulation. Both commercial and generic non-commercial mixture formulations of clothianidin and deltamethrin were tested.
    Results: The clothianidin solo formulation did not show significant contact irritancy relative to the untreated control (3.5 take-offs vs. 3.1 take-offs, p = 0.614) while all deltamethrin-containing IRS induced significant irritant effects. The number of take-offs compared to the clothianidin solo formulation (3.5) was significantly higher with the commercial clothianidin-deltamethrin mixture (6.1, p = 0.001), generic clothianidin-deltamethrin mixture (7.0, p < 0.001), and deltamethrin-only (8.2, p < 0.001) formulations. The commercial clothianidin-deltamethrin mixture induced similar contact irritancy as the generic clothianidin-deltamethrin mixture (6.1 take-offs vs. 7.0 take-offs, p = 0.263) and deltamethrin-only IRS (6.1 take-offs vs. 8.2, p = 0.071), showing that the irritant effect in the mixture was attributable to its deltamethrin component.
    Conclusions: This study provides evidence that the enhanced contact irritancy of the pyrethroid in clothianidin-deltamethrin IRS mixtures can shorten mosquito contact times with treated walls compared to the clothianidin solo formulation. Further trials are needed to directly compare the efficacy of these formulation types under field conditions and establish the impact of this enhanced contact irritancy on the performance of IRS mixture formulations containing pyrethroids.
    MeSH term(s) Animals ; Insecticides/pharmacology ; Anopheles ; Irritants/pharmacology ; Mosquito Control ; Pyrethrins/pharmacology ; Malaria/prevention & control ; Insecticide Resistance ; Mosquito Vectors ; Neonicotinoids ; Guanidines ; Nitriles ; Thiazoles
    Chemical Substances decamethrin (2JTS8R821G) ; clothianidin (2V9906ABKQ) ; Insecticides ; Irritants ; Pyrethrins ; Neonicotinoids ; Guanidines ; Nitriles ; Thiazoles
    Language English
    Publishing date 2024-04-10
    Publishing country England
    Document type Journal Article
    ZDB-ID 2409480-8
    ISSN 1756-3305 ; 1756-3305
    ISSN (online) 1756-3305
    ISSN 1756-3305
    DOI 10.1186/s13071-024-06265-x
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  2. Article ; Online: 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.

    Fongnikin, Augustin / Odjo, Abibath / Akpi, Joel / Kiki, Laurette / Ngufor, Corine

    PloS one

    2022  Volume 17, Issue 4, Page(s) e0267229

    Abstract: 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 ... ...

    Abstract 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.
    MeSH term(s) Animals ; Anopheles ; Benin ; Insecticide Resistance ; Insecticides/pharmacology ; Malaria/prevention & control ; Mosquito Control ; Mosquito Vectors ; Organophosphates/pharmacology ; Organothiophosphorus Compounds ; Pyrethrins/pharmacology
    Chemical Substances Insecticides ; Organophosphates ; Organothiophosphorus Compounds ; Pyrethrins ; pirimiphos methyl (29232-93-7)
    Language English
    Publishing date 2022-04-18
    Publishing country United States
    Document type Clinical Trial ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0267229
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  3. Article ; Online: Investigating discriminating concentrations for monitoring susceptibility to broflanilide and cross resistance to other insecticide classes in Anopheles gambiae sensu lato, using the new WHO bottle bioassay method.

    Govoetchan, Renaud / Odjo, Abibath / Todjinou, Damien / Small, Graham / Fongnikin, Augustin / Ngufor, Corine

    PloS one

    2023  Volume 18, Issue 3, Page(s) e0276246

    Abstract: Background: Broflanilide is a new insecticide being developed for malaria vector control. As new insecticide chemistries become available, strategies to preserve the susceptibility of local malaria vectors and extend their useful life need to be ... ...

    Abstract Background: Broflanilide is a new insecticide being developed for malaria vector control. As new insecticide chemistries become available, strategies to preserve the susceptibility of local malaria vectors and extend their useful life need to be considered before large scale deployment. This requires the development of appropriate testing procedures and identification of suitable discriminating concentrations for monitoring susceptibility in wild vector populations to facilitate decision making by control programmes.
    Methods: Dose-response WHO bottle bioassays were conducted using the insecticide-susceptible Anopheles gambiae s.s. Kisumu strain to determine a discriminating concentration of broflanilide. Bioassays were performed without the adjuvant Mero® and with two concentrations of Mero® (500 ppm and 800 ppm) to investigate its impact on the discriminating concentration of the insecticide. Probit analysis was used to determine the lethal doses at 50% (LC50) and 99% (LC99) at 24-, 48- and 72-hours post-exposure. Cross-resistance to broflanilide and pyrethroids, DDT, dieldrin and carbamates, was investigated using An. gambiae s.l. Covè and An. coluzzii Akron strains. The susceptibility of wild pyrethroid-resistant mosquitoes from communities in Southern Benin to broflanilide was assessed using the estimated discriminating concentrations.
    Results: Broflanilide induced a dose-dependent and delayed mortality effect. Mortality rates in bottles treated without Mero® were <80% using the range of broflanilide doses tested (0-100 μg/bottle) leading to high and unreliable estimates of LC99 values. The discriminating concentrations defined as 2XLC99 at 72h post exposure were estimated to be 2.2 μg/bottle with 800 ppm of Mero® and 6.0 μg/bottle with 500 ppm of Mero®. Very low resistance ratios (0.6-1.2) were determined with the insecticide resistant An. gambiae s.l. Covè and An. coluzzii Akron strains suggesting the absence of cross-resistance via the mechanisms of resistance to pyrethroids, DDT, dieldrin and carbamates they possess. Bottle bioassays performed with broflanilide at both discriminating concentrations of 6 μg/bottle with 500 ppm of Mero® and 2.2 μg/bottle with 800 ppm of Mero®, showed susceptibility of wild highly pyrethroid-resistant An. gambiae s.l. from villages in Southern Benin.
    Conclusion: We determined discriminating concentrations for monitoring susceptibility to broflanilide in bottle bioassays, using susceptible An. gambiae vectors. Using the estimated discriminating concentrations, we showed that wild pyrethroid-resistant populations of An. gambiae s.l. from southern Benin were fully susceptible to the insecticide. Broflanilide also shows potential to be highly effective against An. gambiae s.l. vector populations that have developed resistance to other public health insecticides.
    MeSH term(s) Animals ; Humans ; Insecticides/pharmacology ; Anopheles ; Dieldrin/pharmacology ; DDT/pharmacology ; Insecticide Resistance ; Mosquito Vectors ; Malaria ; Pyrethrins/pharmacology ; Mosquito Control/methods ; Carbamates/pharmacology ; Biological Assay ; World Health Organization
    Chemical Substances Insecticides ; 3-benzamido-N-(4-(perfluoropropan-2-yl)phenyl)benzamide ; Dieldrin (I0246D2ZS0) ; DDT (CIW5S16655) ; Pyrethrins ; Carbamates
    Language English
    Publishing date 2023-03-23
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0276246
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  4. Article ; Online: Pyrethroid-piperonyl butoxide (PBO) nets reduce the efficacy of indoor residual spraying with pirimiphos-methyl against pyrethroid-resistant malaria vectors.

    Syme, Thomas / Gbegbo, Martial / Obuobi, Dorothy / Fongnikin, Augustin / Agbevo, Abel / Todjinou, Damien / Ngufor, Corine

    Scientific reports

    2022  Volume 12, Issue 1, Page(s) 6857

    Abstract: Pirimiphos-methyl is a pro-insecticide requiring activation by mosquito cytochrome P450 enzymes to induce toxicity while PBO blocks activation of these enzymes in pyrethroid-resistant vector mosquitoes. PBO may thus antagonise the toxicity of pirimiphos- ... ...

    Abstract Pirimiphos-methyl is a pro-insecticide requiring activation by mosquito cytochrome P450 enzymes to induce toxicity while PBO blocks activation of these enzymes in pyrethroid-resistant vector mosquitoes. PBO may thus antagonise the toxicity of pirimiphos-methyl IRS when combined with pyrethroid-PBO ITNs. The impact of combining Olyset Plus and PermaNet 3.0 with Actellic 300CS IRS was evaluated against pyrethroid-resistant Anopheles gambiae s.l. in two parallel experimental hut trials in southern Benin. The vector population was resistant to pyrethroids and PBO pre-exposure partially restored deltamethrin toxicity but not permethrin. Mosquito mortality in experimental huts was significantly improved in the combinations of bendiocarb IRS with pyrethroid-PBO ITNs (33-38%) compared to bendiocarb IRS alone (14-16%, p < 0.001), demonstrating an additive effect. Conversely, mortality was significantly reduced in the combinations of pirimiphos-methyl IRS with pyrethroid-PBO ITNs (55-59%) compared to pirimiphos-methyl IRS alone (77-78%, p < 0.001), demonstrating evidence of an antagonistic effect when both interventions are applied in the same household. Mosquito mortality in the combination was significantly higher compared to the pyrethroid-PBO ITNs alone (55-59% vs. 22-26% p < 0.001) showing potential of pirimiphos-methyl IRS to enhance vector control when deployed to complement pyrethroid-PBO ITNs in an area where PBO fails to fully restore susceptibility to pyrethroids.
    MeSH term(s) Animals ; Anopheles ; Insecticide Resistance ; Malaria/prevention & control ; Mosquito Control ; Mosquito Vectors ; Organothiophosphorus Compounds ; Piperonyl Butoxide/pharmacology ; Pyrethrins/toxicity
    Chemical Substances Organothiophosphorus Compounds ; Pyrethrins ; pirimiphos methyl (29232-93-7) ; Piperonyl Butoxide (LWK91TU9AH)
    Language English
    Publishing date 2022-04-27
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-022-10953-y
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  5. Article ; Online: PermaNet Dual, a new deltamethrin-chlorfenapyr mixture net, shows improved efficacy against pyrethroid-resistant Anopheles gambiae sensu lato in southern Benin.

    Syme, Thomas / N'dombidjé, Boris / Gbegbo, Martial / Todjinou, Damien / Ariori, Victoria / De Vos, Patricia / Pigeon, Olivier / Ngufor, Corine

    Scientific reports

    2023  Volume 13, Issue 1, Page(s) 12232

    Abstract: Pyrethroid-chlorfenapyr nets have demonstrated improved entomological and epidemiological impact in trials across Africa. This is driving increased demand for this novel net class in malaria-endemic countries. PermaNet Dual is a new deltamethrin- ... ...

    Abstract Pyrethroid-chlorfenapyr nets have demonstrated improved entomological and epidemiological impact in trials across Africa. This is driving increased demand for this novel net class in malaria-endemic countries. PermaNet Dual is a new deltamethrin-chlorfenapyr net developed by Vestergaard Sàrl to provide more options to malaria control programmes. We performed an experimental hut trial to evaluate the efficacy of PermaNet Dual against wild, free-flying pyrethroid-resistant Anopheles gambiae sensu lato in Covè, Benin. PermaNet Dual induced superior levels of mosquito mortality compared to a pyrethroid-only net and a pyrethroid-piperonyl butoxide net both when unwashed (77% with PermaNet Dual vs. 23% with PermaNet 2.0 and 56% with PermaNet 3.0, p < 0.001) and after 20 standardised washes (75% with PermaNet Dual vs. 14% with PermaNet 2.0 and 30% with PermaNet 3.0, p < 0.001). Using a provisional non-inferiority margin defined by the World Health Organisation, PermaNet Dual was also non-inferior to a pyrethroid-chlorfenapyr net that has demonstrated improved public health value (Interceptor G2), for vector mortality (79% vs. 76%, OR = 0.878, 95% CIs 0.719-1.073) but not for blood-feeding protection (35% vs. 26%, OR = 1.424, 95% CIs 1.177-1.723). PermaNet Dual presents an additional option of this highly effective net class for improved control of malaria transmitted by pyrethroid-resistant mosquitoes.
    MeSH term(s) Animals ; Humans ; Anopheles ; Insecticides/pharmacology ; Benin/epidemiology ; Mosquito Control ; Insecticide-Treated Bednets ; Mosquito Vectors ; Pyrethrins/pharmacology ; Malaria/prevention & control ; Insecticide Resistance
    Chemical Substances decamethrin (2JTS8R821G) ; chlorfenapyr (NWI20P05EB) ; Insecticides ; Pyrethrins
    Language English
    Publishing date 2023-07-28
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-023-39140-3
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  6. Article ; Online: Can the performance of pyrethroid-chlorfenapyr nets be reduced when combined with pyrethroid-piperonyl butoxide (PBO) nets?

    Syme, Thomas / Nounagnon, Judicaël / N'dombidjé, Boris / Gbegbo, Martial / Agbevo, Abel / Ahoga, Juniace / Ngufor, Corine

    Malaria journal

    2023  Volume 22, Issue 1, Page(s) 214

    Abstract: Background: Pyrethroid-chlorfenapyr (CFP) and pyrethroid-piperonyl butoxide (PBO) nets are being scaled across endemic countries to improve control of malaria transmitted by pyrethroid-resistant mosquitoes. CFP is a pro-insecticide requiring activation ... ...

    Abstract Background: Pyrethroid-chlorfenapyr (CFP) and pyrethroid-piperonyl butoxide (PBO) nets are being scaled across endemic countries to improve control of malaria transmitted by pyrethroid-resistant mosquitoes. CFP is a pro-insecticide requiring activation by mosquito cytochrome P450 monooxygenase enzymes (P450s) while PBO improves pyrethroid potency by inhibiting the action of these enzymes in pyrethroid-resistant mosquitoes. The inhibitory action of PBO against P450s may thus reduce the efficacy of pyrethroid-CFP nets when applied inside the same household as pyrethroid-PBO nets.
    Methods: Two experimental hut trials were performed to evaluate the entomological impact of two different types of pyrethroid-CFP ITN (Interceptor
    Results: The vector population was susceptible to CFP but exhibited a high intensity of pyrethroid resistance that was overcame by PBO pre-exposure. Vector mortality was significantly lower in huts with combinations of pyrethroid-CFP nets plus pyrethroid-PBO nets compared to huts with two pyrethroid-CFP nets (74% vs. 85% for Interceptor
    Conclusions: This study shows evidence of a reduced performance of pyrethroid-CFP nets when combined with pyrethroid-PBO ITNs compared to when applied alone and higher efficacy with net combinations that included pyrethroid-CFP nets. These findings suggest that in similar contexts, prioritizing distribution of pyrethroid-CFP nets over other net types would maximize vector control impact.
    MeSH term(s) Animals ; Piperonyl Butoxide/pharmacology ; Mosquito Control ; Anopheles ; Insecticide-Treated Bednets ; Mosquito Vectors ; Pyrethrins/pharmacology ; Insecticides/pharmacology ; Insecticide Resistance
    Chemical Substances chlorfenapyr (NWI20P05EB) ; milbemycin oxime (0502PUN0GT) ; Piperonyl Butoxide (LWK91TU9AH) ; Pyrethrins ; Insecticides
    Language English
    Publishing date 2023-07-21
    Publishing country England
    Document type Journal Article
    ZDB-ID 2091229-8
    ISSN 1475-2875 ; 1475-2875
    ISSN (online) 1475-2875
    ISSN 1475-2875
    DOI 10.1186/s12936-023-04648-6
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  7. Article: Community evaluation of the physical and insecticidal durability of DuraNet® Plus, an alpha-cypermethrin and piperonyl butoxide incorporated mosquito net: protocol for a multi-country study in West, Central and East Africa.

    Agbevo, Abel / Ahogni, Idelphonse / Menze, Benjamin / Tungu, Patrick / Kemibala, Elison E / Govoetchan, Renaud / Wondji, Charles / Padonou, Germain Gil / Ngufor, Corine

    Archives of public health = Archives belges de sante publique

    2023  Volume 81, Issue 1, Page(s) 202

    Abstract: Background: Pyrethroid-PBO nets have demonstrated improved impact against clinical malaria transmitted by pyrethroid resistant mosquito vectors and are being scaled up across Africa. However very little is known about their physical and insecticidal ... ...

    Abstract Background: Pyrethroid-PBO nets have demonstrated improved impact against clinical malaria transmitted by pyrethroid resistant mosquito vectors and are being scaled up across Africa. However very little is known about their physical and insecticidal durability under operational conditions. This study will investigate the attrition, fabric integrity, insecticide content and bioefficacy of DuraNet® Plus, a new WHO prequalified alphacypermethrin and PBO incorporated net developed by Shobikaa Impex Private Limited over 3 years of field use in communities in Benin, Cameroon and Tanzania.
    Methods: The study will be conducted in parallel in selected villages in Zakpota District in Benin, Mbalmayo, District in Cameroon and Muheza District in Tanzania. In each country, ~ 1800 households will be recruited and randomised to receive DuraNet® Plus or DuraNet® (a WHO prequalified alphacypermethrin-only ITN). Follow up surveys will be performed at 1 month post distribution to investigate adverse events and subsequently every 6-12 months to assess ITN attrition and fabric integrity following standard WHO procedures. A second cohort of nets will be withdrawn every 6-12 months and assessed for alpha-cypermethrin and PBO content and for entomological activity in laboratory bioassays (cone bioassays and tunnel tests). Alpha-cypermethrin bioefficacy will be monitored using the susceptible Anopheles gambiae Kisumu strain in cone bioassays while PBO bioefficacy will be monitored using pyrethroid resistant strains with overexpressed P450 enzymes in tunnel tests to determine the proportion of efficacious nets (≥ 95% knockdown, ≥ 80% mortality or ≥ 90% blood feeding inhibition in tunnels) at each time point. Nets withdrawn at 12, 24 and 36 months from each country will also be tested in experimental hut trials against wild free-flying pyrethroid resistant Anopheles gambiae sl in Côvè Benin to investigate the superiority of DuraNet® Plus over DuraNet® at each time point under semi field conditions.
    Conclusion: This large-scale multi country trial will provide useful information on the durability of a pyrethroid-PBO net (DuraNet® Plus) in 3 different regions in sub-Saharan Africa. The methods proposed for bioefficacy testing could also contribute towards the development of new standardised guidelines for monitoring the insecticidal efficacy of pyrethroid-PBO nets under operational conditions.
    Language English
    Publishing date 2023-11-20
    Publishing country England
    Document type Journal Article
    ZDB-ID 1117688-x
    ISSN 2049-3258 ; 0778-7367 ; 0003-9578
    ISSN (online) 2049-3258
    ISSN 0778-7367 ; 0003-9578
    DOI 10.1186/s13690-023-01217-w
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  8. Article ; Online: Efficacy of Royal Guard, a new alpha-cypermethrin and pyriproxyfen treated mosquito net, against pyrethroid-resistant malaria vectors.

    Ngufor, Corine / Agbevo, Abel / Fagbohoun, Josias / Fongnikin, Augustin / Rowland, Mark

    Scientific reports

    2020  Volume 10, Issue 1, Page(s) 12227

    Abstract: Royal Guard is a new insecticide-treated bed-net incorporated with a mixture of alpha-cypermethrin and pyriproxyfen (an insect growth regulator). We assessed its efficacy and wash-resistance in laboratory and experimental hut studies following WHO ... ...

    Abstract Royal Guard is a new insecticide-treated bed-net incorporated with a mixture of alpha-cypermethrin and pyriproxyfen (an insect growth regulator). We assessed its efficacy and wash-resistance in laboratory and experimental hut studies following WHO guidelines. Mosquitoes that survived exposure to the net were kept in separate oviposition chambers and observed for the reproductive effects of pyriproxyfen. In laboratory assays, Royal Guard induced > 80% mortality and > 90% blood-feeding inhibition of An. gambiae sl mosquitoes before and after 20 standardised washes and sterilised blood-fed mosquitoes which remained alive after exposure to the net. In an experimental hut trial against wild free-flying pyrethroid-resistant An. gambiae sl in Cové Benin, Royal Guard through the pyrethroid component induced comparable levels of mortality and blood-feeding inhibition to a standard pyrethroid-only treated net before and after 20 washes and sterilised large proportions of surviving blood-fed female mosquitoes through the pyriproxyfen component; Royal Guard induced 83% reduction in oviposition and 95% reduction in offspring before washing and 25% reduction in oviposition and 50% reduction in offspring after 20 washes. Royal Guard has the potential to improve malaria vector control and provide better community protection against clinical malaria in pyrethroid-resistant areas compared to standard pyrethroid-only LLINs.
    MeSH term(s) Animals ; Anopheles/drug effects ; Benin ; Female ; Insecticide Resistance/drug effects ; Insecticide-Treated Bednets ; Insecticides/pharmacology ; Malaria/prevention & control ; Mosquito Control/instrumentation ; Mosquito Control/methods ; Mosquito Vectors/drug effects ; Oviposition/drug effects ; Pyrethrins/pharmacology ; Pyridines/pharmacology
    Chemical Substances Insecticides ; Pyrethrins ; Pyridines ; cypermethrin (1TR49121NP) ; pyriproxyfen (3Q9VOR705O)
    Language English
    Publishing date 2020-07-22
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-020-69109-5
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Efficacy of broflanilide (VECTRON T500), a new meta-diamide insecticide, for indoor residual spraying against pyrethroid-resistant malaria vectors.

    Ngufor, Corine / Govoetchan, Renaud / Fongnikin, Augustin / Vigninou, Estelle / Syme, Thomas / Akogbeto, Martin / Rowland, Mark

    Scientific reports

    2021  Volume 11, Issue 1, Page(s) 7976

    Abstract: The rotational use of insecticides with different modes of action for indoor residual spraying (IRS) is recommended for improving malaria vector control and managing insecticide resistance. Insecticides with new chemistries are urgently needed. ... ...

    Abstract The rotational use of insecticides with different modes of action for indoor residual spraying (IRS) is recommended for improving malaria vector control and managing insecticide resistance. Insecticides with new chemistries are urgently needed. Broflanilide is a newly discovered insecticide under consideration. We investigated the efficacy of a wettable powder (WP) formulation of broflanilide (VECTRON T500) for IRS on mud and cement wall substrates in laboratory and experimental hut studies against pyrethroid-resistant malaria vectors in Benin, in comparison with pirimiphos-methyl CS (Actellic 300CS). There was no evidence of cross-resistance to pyrethroids and broflanilide in CDC bottle bioassays. In laboratory cone bioassays, broflanilide WP-treated substrates killed > 80% of susceptible and pyrethroid-resistant An. gambiae sl for 6-14 months. At application rates of 100 mg/m
    MeSH term(s) Animals ; Anopheles/drug effects ; Benin ; Benzamides/toxicity ; Biological Assay ; Insecticide Resistance/drug effects ; Insecticides/toxicity ; Malaria/parasitology ; Mosquito Vectors/drug effects ; Pyrethrins/toxicity ; World Health Organization
    Chemical Substances 3-benzamido-N-(4-(perfluoropropan-2-yl)phenyl)benzamide ; Benzamides ; Insecticides ; Pyrethrins
    Language English
    Publishing date 2021-04-12
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-021-86935-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: The Automatic Classification of Pyriproxyfen-Affected Mosquito Ovaries

    Fowler, Mark T. / Lees, Rosemary S. / Fagbohoun, Josias / Matowo, Nancy S. / Ngufor, Corine / Protopopoff, Natacha / Spiers, Angus

    Insects. 2021 Dec. 17, v. 12, no. 12

    2021  

    Abstract: Pyriproxyfen (PPF) may become an alternative insecticide for areas where pyrethroid-resistant vectors are prevalent. The efficacy of PPF can be assessed through the dissection and assessment of vector ovaries. However, this reliance on expertise is ... ...

    Abstract Pyriproxyfen (PPF) may become an alternative insecticide for areas where pyrethroid-resistant vectors are prevalent. The efficacy of PPF can be assessed through the dissection and assessment of vector ovaries. However, this reliance on expertise is subject to limitations. We show here that these limitations can be overcome using a convolutional neural network (CNN) to automate the classification of egg development and thus fertility status. Using TensorFlow, a resnet-50 CNN was pretrained with the ImageNet dataset. This CNN architecture was then retrained using a novel dataset of 524 dissected ovary images from An. gambiae s.l. An. gambiae Akron, and An. funestus s.l., whose fertility status and PPF exposure were known. Data augmentation increased the training set to 6973 images. A test set of 157 images was used to measure accuracy. This CNN model achieved an accuracy score of 94%, and application took a mean time of 38.5 s. Such a CNN can achieve an acceptable level of precision in a quick, robust format and can be distributed in a practical, accessible, and free manner. Furthermore, this approach is useful for measuring the efficacy and durability of PPF treated bednets, and it is applicable to any PPF-treated tool or similarly acting insecticide.
    Keywords Culicidae ; bed nets ; data collection ; dissection ; durability ; eggs ; neural networks ; pyriproxyfen
    Language English
    Dates of publication 2021-1217
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2662247-6
    ISSN 2075-4450
    ISSN 2075-4450
    DOI 10.3390/insects12121134
    Database NAL-Catalogue (AGRICOLA)

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