Insecticide resistance status of malaria vectors Anopheles gambiae (s.l.) of southwest Burkina Faso and residual efficacy of indoor residual spraying with microencapsulated pirimiphos-methyl insecticide

Abstract

Background The rapid spread of insecticide resistance in malaria vectors and the rebound in malaria cases observed recently in some endemic areas underscore the urgent need to evaluate and deploy new effective control interventions. A randomized control trial (RCT) was conducted with the aim to investigate the benefit of deploying complementary strategies, including indoor residual spraying (IRS) with pirimiphos-methyl in addition to long-lasting insecticidal nets (LLINs) in Diébougou, southwest Burkina Faso. Methods We measured the susceptibility of the Anopheles gambiae (s.l.) population from Diébougou to conventional insecticides. We further monitored the efficacy and residual activity of pirimiphos-methyl on both cement and mud walls using a laboratory susceptible strain (Kisumu) and the local An. gambiae (s.l.) population. Results An. gambiae (s.l.) from Diébougou was resistant to DDT, pyrethroids (deltamethrin, permethrin and alphacypermethrin) and bendiocarb but showed susceptibility to organophosphates (pirimiphos-methyl and chlorpyrimiphos-methyl). A mixed-effect generalized linear model predicted that pirimiphos-methyl applied on cement or mud walls was effective for 210 days against the laboratory susceptible strain and 247 days against the local population. The residual efficacy of pirimiphos-methyl against the local population on walls made of mud was similar to that of cement (OR = 0.792, [0.55–1.12], Tukey’s test p-value = 0.19). Conclusions If data on malaria transmission and malaria cases (as measured trough the RCT) are consistent with data on residual activity of pirimiphos-methyl regardless of the type of wall, one round of IRS with pirimiphos-methyl would have the potential to control malaria in a context of multi-resistant An. gambiae (s.l.) for at least 7 months.

Assessing Insecticide Susceptibility Status of Anopheles Mosquitoes in Gondar Zuria District, Northwest Ethiopia

“…Mortality rates of 98-100% indicate susceptibility, 90-97% indicate a candidate for resistance (further investigation is needed), and less than 90% indicate resistance(76), as shown in Table-3. Previous ndings from Burkina Faso, Uganda, Mali, Rwanda, Kenya, and Tanzania agree with this one from 2005 to 2017 (16, 34,36,37,[54][55][56][57].…”

Spatial-temporal pattern of malaria in Burkina Faso from 2013 to 2020

“…populations to insecticides in several regions in Burkina Faso ( Dabiré et al, 2008 ; Namountougou et al, 2012 ). These resistances are thought to be due to the pressure of insecticides used against adult mosquitoes in households (LLINs, IRS), to the pressure exerted on larvae in breeding sites contaminated by insecticides used in agriculture, to the use of repellents in homes ( Soma et al, 2021 ). In addition, antimalarial drug resistance in Plasmodium spp.…”

Insecticide resistance intensity and efficacy of synergists with pyrethroids in Anopheles gambiae s.l. (Diptera: Culicidae) from Southern Togo

“…However, the emergence of resistance to the main classes of insecticides used in the treatment of bed nets and in indoor residual spraying (IRS) requires re-thinking the use of these tools and the management of resistance in vectors [2]. Resistance has already been reported in various West African countries including Benin, Burkina Faso, Mali [3][4][5] and particularly in Togo [6,7]. Recent studies showed that the use of synergists and combination of insecticide formulations can increase the susceptibility of malaria vectors in areas with high pyrethroid resistance [8,9].…”