Efficacy of mosquito nets treated with insecticide mixtures or mosaics against insecticide resistant Anopheles gambiae and Culex quinquefasciatus (Diptera: Culicidae) in Côte d'Ivoire

2003 ◽  
Vol 93 (6) ◽  
pp. 491-498 ◽  
Author(s):  
J.-M. Hougard ◽  
V. Corbel ◽  
R. N'Guessan ◽  
F. Darriet ◽  
F. Chandre ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Culex Quinquefasciatus ◽  
Resistance Management ◽  
Blood Feeding ◽  
Malaria Vectors ◽  
Mosquito Net ◽  
Pyrethroid Insecticides ◽  
Mosquito Nets ◽  
Experimental Huts ◽  
Insecticide Mixtures

AbstractOnly pyrethroid insecticides have so far been recommended for the treatment of mosquito nets for malaria control. Increasing resistance of malaria vectors to pyrethroids threatens to reduce the potency of this important method of vector control. Among the strategies proposed for resistance management is to use a pyrethroid and a non-pyrethroid insecticide in combination on the same mosquito net, either separately or as a mixture. Mixtures are particularly promising if there is potentiation between the two insecticides as this would make it possible to lower the dosage of each, as has been demonstrated under laboratory conditions for a mixture of bifenthrin (pyrethroid) and carbosulfan (carbamate). The effect of these types of treatment were compared in experimental huts on wild populations of Anopheles gambiae Giles and the nuisance mosquito Culex quinquefasciatus Say, both of which are multi-resistant. Four treatments were evaluated in experimental huts over six months: the recommended dosage of 50 mg m−2 bifenthrin, 300 mg m−2 carbosulfan, a mosaic of 300 mg m−2 carbosulfan on the ceiling and 50 mg m−2 bifenthrin on the sides, and a mixture of 6.25 mg m−2 carbosulfan and 25 mg m−2 bifenthrin. The mixture and mosaic treatments did not differ significantly in effectiveness from carbosulfan and bifenthrin alone against anophelines in terms of deterrency, induced exophily, blood feeding inhibition and overall mortality, but were more effective than in earlier tests with deltamethrin. These results are considered encouraging, as the combination of different classes of insecticides might be a potential tool for resistance management. The mixture might have an advantage in terms of lower cost and toxicity.

scholarly journals Human biting rhythm of Anopheles gambiae Giles, 1902 (Diptera: Culicidae) and sleeping behaviour of pregnant women in a lagoon area in Southern Benin

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Armel Djènontin ◽  
Aziz Bouraima ◽  
Christophe Soares ◽  
Seun Egbinola ◽  
Gilles Cottrell
Keyword(s):  
Plasmodium Falciparum ◽  
Pregnant Women ◽  
Anopheles Gambiae ◽  
Early Morning ◽  
Allelic Frequency ◽  
Malaria Vectors ◽  
Mosquito Nets ◽  
Anopheles Gambiae Giles ◽  
Almost All ◽  
Southern Benin

Abstract Objective In the framework of EVALMOUS study aiming to assess the use and effectiveness of mosquito nets by pregnant women and other members of their household in a lagoon area in southern Benin, the behaviour of pregnant women relative to the time they go to bed using the net were recorded. Malaria vectors biting rhythm, Plasmodium falciparum infection and insecticide resistance genes in malaria vectors were also determined. Results Overall, 3848 females of Anopheles gambiae s. l were collected and 280 pregnant women responded to the survey. Almost all Anopheles gambiae s. l. tested were Anopheles coluzzi Coetzee and Wilkerson 2013 (Diptera: Culicidae). The CSP index in malaria vector was 1.85% and the allelic frequency of kdr gene was 74.4%. Around 90% of bites and Plasmodium falciparum Welch, 1897 (Haemosporida: Plasmodiidae) transmission occurred between 10 p.m. and 6 a.m., which coincides with the period when more than 80% of pregnant women were under bednet. Despite a slight early evening and early morning biting activity of malaria vectors in the study area, the good use of nets might remain a useful protection tool against mosquito biting and malaria transmission.

scholarly journals Susceptibility of Anopheles gambiae from Côte d’Ivoire to insecticides used on insecticide-treated nets: evaluating the additional entomological impact of piperonyl butoxide and chlorfenapyr

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Bernard L. Kouassi ◽  
Constant Edi ◽  
Emmanuel Tia ◽  
Lucien Y. Konan ◽  
Maurice A. Akré ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Resistance Management ◽  
Piperonyl Butoxide ◽  
Assay Method ◽  
Insecticide Treated Nets ◽  
Cote D’Ivoire ◽  
Pyrethroid Insecticides ◽  
Côte D'ivoire

Abstract Background Pyrethroid-treated mosquito nets are currently the mainstay of vector control in Côte d’Ivoire. However, resistance to pyrethroids has been reported across the country, limiting options for insecticide resistance management due to the paucity of alternative insecticides. Two types of insecticide-treated nets (ITNs), ITNs with pyrethroids and the synergist piperonyl butoxide (PBO), and Interceptor®G2 nets, a net treated with a combination of chlorfenapyr and alpha-cypermethrin, are believed to help in the control of pyrethroid-resistant mosquitoes. Methods The susceptibility of Anopheles gambiae sensu lato (s.l.) to pyrethroid insecticides with and without pre-exposure to PBO as well as to chlorfenapyr was investigated in fifteen sites across the country. Susceptibility tests were conducted on 2- to 4-day old adult female An. gambiae s.l. reared from larval collections. The resistance status, intensity, and effects of PBO on mortality after exposure to different concentrations of deltamethrin, permethrin and alpha-cypermethrin were determined using WHO susceptibility test kits. In the absence of a WHO-recommended standard protocol for chlorfenapyr, two interim doses (100 and 200 µg/bottle) were used to test the susceptibility of mosquitoes using the CDC bottle assay method. Results Pre-exposure to PBO did not result in full restoration of susceptibility to any of the three pyrethroids for the An. gambiae s.l. populations from any of the sites surveyed. However, PBO pre-exposure did increase mortality for all three pyrethroids, particularly deltamethrin (from 4.4 to 48.9%). Anopheles gambiae s.l. from only one site (Bettie) were susceptible to chlorfenapyr at the dose of 100 µg active ingredient (a.i.)/bottle. At the dose of 200 µg (a.i.)/bottle, susceptibility was only recorded in 10 of the 15 sites. Conclusion Low mosquito mortality was found for pyrethroids alone, and while PBO increased mortality, it did not restore full susceptibility. The vector was not fully susceptible to chlorfenapyr in one third of the sites tested. However, vector susceptibility to chlorfenapyr seems to be considerably higher than for pyrethroids alone or with PBO. These data should be used cautiously when making ITN procurement decisions, noting that bioassays are conducted in controlled conditions and may not fully represent field efficacy where the host-seeking behaviours, which include free-flying activity are known to enhance pro-insecticide chlorfenapyr intoxication to mosquitoes.

scholarly journals Susceptibility of Anopheles gambiae sensu lato from Côte d’Ivoire to insecticides used on insecticide-treated nets: evaluating the additional entomological impact of piperonyl butoxide and chlorfenapyr

2020 ◽  
Author(s):  
Bernard L. Kouassi ◽  
Constant Edi ◽  
Emmanuel Tia ◽  
Lucien Y. Konan ◽  
Maurice A. Akré ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Resistance Management ◽  
Piperonyl Butoxide ◽  
Assay Method ◽  
Insecticide Treated Nets ◽  
Cote D’Ivoire ◽  
Pyrethroid Insecticides ◽  
Côte D'ivoire

Abstract BackgroundPyrethroid-treated mosquito nets are currently the mainstay of vector control in Côte d’Ivoire. However, resistance to pyrethroids has been reported across the country, limiting options for insecticide resistance management due to the paucity of alternative insecticides. Two types of insecticide-treated nets (ITNs), ITNs with pyrethroids and the synergist piperonyl butoxide (PBO), and Interceptor®G2 nets, a net treated with a combination of chlorfenapyr and alpha-cypermethrin, are believed to help in the control of pyrethroid-resistant mosquitoes. MethodsThe susceptibility of Anopheles gambiae sensu lato (s.l.) to pyrethroid insecticides with and without pre-exposure to PBO as well as to chlorfenapyr was investigated in fifteen sites across the country. Susceptibility tests were conducted on 2- to 4-day old adult female An. gambiae s.l. reared from larval collections. The resistance status, intensity, and effects of PBO on mortality after exposure to different concentrations of deltamethrin, permethrin and alpha-cypermethrin were determined using WHO susceptibility test kits. In the absence of a WHO-recommended standard protocol for chlorfenapyr, two interim doses (100 and 200 µg/bottle) were used to test the susceptibility of mosquitoes using the CDC bottle assay method. ResultsPre-exposure to PBO did not result in full restoration of susceptibility to any of the three pyrethroids for the An. gambiae s.l. populations from any of the sites surveyed. However, PBO pre-exposure did increase mortality for all three pyrethroids, particularly deltamethrin (from 4.4% to 48.9%). Anopheles gambiae s.l. from only one site (Bettie) were susceptible to chlorfenapyr at the dose of 100 µg active ingredient (a.i.)/bottle. At the dose of 200 µg (a.i.)/bottle, susceptibility was only recorded in 10 of the 15 sites.ConclusionLow mosquito mortality was found for pyrethroids alone, and while PBO increased mortality, it did not restore full susceptibility. The vector was not fully susceptible to chlorfenapyr in one third of the sites tested. However, vector susceptibility to chlorfenapyr seems to be considerably higher than for pyrethroids alone or with PBO. These data should be used cautiously when making ITN procurement decisions, noting that bioassays are conducted in controlled conditions and may not fully represent field efficacy where the host-seeking behaviors which include free-flying activity are known to enhance pro-insecticide chlorfenapyr intoxication to mosquitoes.

scholarly journals Deteksi Gen Kdr pada Nyamuk Anopheles di Kabupaten Maluku Tenggara Barat

2021 ◽  
pp. 161-170
Author(s):  
Hanna S.I Kawulur ◽  
Hotma Martogi Lorensi Hutapea ◽  
Ivon Ayomi ◽  
Melda Suebu ◽  
Mardi Raharjo Pardi
Keyword(s):  
Malaria Vectors ◽  
Bed Nets ◽  
Morbidity Rate ◽  
Gene Detection ◽  
Paper Test ◽  
Anopheles Subpictus ◽  
Pyrethroid Insecticides ◽  
Mosquito Nets ◽  
Development Center ◽  
Anopheles Barbirostris

Malaria is still a health problem in Indonesia, particularly in Eastern part of Indonesia. The use of LLIN insecticide bed nets is one of the efforts to reduce the malaria morbidity rate by protecting human from malaria vector bites. The Anopheles flavirostris, Anopheles barbirostris, and Anopheles subpictus mosquitoes are three of the species reported as malaria vectors in West-Southeast Maluku Regency. The aim of this research was to detect the kdr gene in An. flavirostris, An. barbirostris, and An.subpictus mosquitoes collected from Alusi Kelaan village, West-Southeast Maluku Regency. The research was conducted at the Papua Biomedical Research and Development Center, in June 2016. A total of six An. flavirostris, 42 An. barbirostris, and 24 An. subpictus were pooled separately for genomic DNA extraction. The sample used was the An. flavirostris, An. barbirostris, and An. subpictus that survived after the impregnated paper test. The kdr gene detection was carried out using quantitative PCR (qPCR) focused on points V1010 and L1014. The results showed that there were no kdr mutant strains in the An. flavirostris, An. barbirostris, and An. subpictus. These results indicated that the sensitivity of pyrethroid insecticides contained in LLIN mosquito nets to An. flavirostris, An. barbirostris, and An. subpictus mosquitoes was not decreased in West Southeast Maluku Regency.

scholarly journals Identification of a rapidly-spreading triple mutant for high-level metabolic insecticide resistance in Anopheles gambiae provides a real-time molecular diagnostic for anti-malarial intervention deployment

2021 ◽  
Author(s):  
Harun Njoroge ◽  
Arjen van’t Hof ◽  
Ambrose Oruni ◽  
Dimitra Pipini ◽  
Sanjay C. Nagi ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Anopheles Gambiae ◽  
Pyrethroid Resistance ◽  
Border Region ◽  
Malaria Vectors ◽  
Molecular Diagnostic ◽  
Triple Mutant ◽  
Pyrethroid Insecticides ◽  
High Level ◽  
Mutant Haplotype

AbstractInsecticide resistance provides both an increasingly pressing threat to the control of vector-borne diseases and insights into the remarkable capacity of natural populations to show rapid evolutionary responses to contemporary selection. Malaria control remains heavily dependent on deployment of pyrethroid insecticides, primarily in long lasting insecticidal nets (LLINs), but resistance in the major malaria vectors has increased over the last 15 years in concert with dramatic expansion of LLIN distributions. Identifying genetic mechanisms underlying high-level resistance in mosquitoes, which may almost entirely overcome pyrethroid efficacy, is crucial for the development and deployment of potentially resistance-breaking tools. Using the Anopheles gambiae 1000 genomes (Ag1000g) data we identified a very recent selective sweep in mosquitoes from Uganda which localized to a cluster of cytochrome P450 genes, including some commonly implicated in resistance. Further interrogation revealed a haplotype involving a trio of mutations, a nonsynonymous point mutation in Cyp6p4 (I236M), an upstream insertion of a partial Zanzibar-like transposable element (TE) and a duplication of the Cyp6aa1 gene. The mutations appear to have originated recently in An. gambiae from the Kenya-Uganda border region around Lake Victoria, with stepwise replacement of the double-mutant (Zanzibar-like TE and Cyp6p4-236M) with the triple-mutant haplotype (including Cyp6aa1 duplication), which has spread into the Democratic Republic of Congo and Tanzania. The triple-mutant haplotype is strongly associated with increased expression of genes able to metabolise pyrethroids and is strongly predictive of resistance to pyrethroids most notably deltamethrin, a commonly-used LLIN insecticide. Importantly, there was increased mortality in mosquitoes carrying the triple-mutation when exposed to nets co-treated with the synergist piperonyl butoxide (PBO). Frequencies of the triple-mutant haplotype remain spatially variable within countries, suggesting an effective marker system to guide deployment decisions for limited supplies of PBO-pyrethroid co-treated LLINs across African countries. Duplications of the Cyp6aa1 gene are common in An. gambiae across Africa and, given the enzymes metabolic activity, are likely to be a useful diagnostic for high levels of pyrethroid resistance.

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