Impact of insecticide resistance in Anopheles arabiensis on malaria incidence and prevalence in Sudan and the costs of mitigation

Abstract

SignificanceEmerging insecticide resistance in malaria vectors could presage a catastrophic rebound in malaria morbidity and mortality. In areas of moderate levels of resistance to pyrethroids, long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) with a carbamate insecticide were significantly more effective than IRS with pyrethroid insecticide. The impact on the effectiveness of LLINs could not be quantified. The incremental cost of using a carbamate insecticide to which vectors are susceptible was US $0.65 per person protected per year, which is considered acceptable by international standards. While the WHO recommends that different interventions, where possible, should use different insecticide classes, these data alone should not be used as the basis for a policy change in vector control interventions.

Indoor residual spraying for preventing malaria in communities using insecticide-treated nets

“…Three trials (providing four comparisons) used a non‐pyrethroid‐like IRS throughout the trial (Corbel 2012; Protopopoff 2018; West 2014), and two trials (providing two comparisons) used a pyrethroid‐like IRS throughout (Keating 2011; Pinder 2015). One further trial used a pyrethroid‐like insecticide in the first study year, but replaced it with a non‐pyrethroid‐like insecticide for the two subsequent years, and therefore provided two different comparisons (Kafy 2017). …”

“…The four trials evaluating the effect of non‐pyrethroid‐like IRS were conducted in sub‐Saharan Africa; one in southern Benin (Corbel 2012); one in south‐eastern Sudan (Kafy 2017), and two in north‐west Tanzania (Protopopoff 2018; West 2014). The former two regions experience seasonal transmission, while north‐west Tanzania has perennial transmission with two peak seasons.…”

“…Two trials evaluated the effect of adding IRS to ITNs using a two‐armed study design (Kafy 2017; West 2014). Two trials had four arms.…”

“…IRS application coverage was described as 80% of households in the study area (Corbel 2012), consistently above 80% (Kafy 2017), 94% in both IRS intervention arms (Protopopoff 2018), and 89.3% to 92.1% (West 2014). …”

“…Two trials used a WP formulation of the carbamate bendiocarb, at a dose of 400 mg/m² (Corbel 2012; West 2014), and in the second year of another trial (Kafy 2017). Protopopoff 2018 used Actellic 300CS (a commercial formulation of pirimiphos‐methyl), at a dosage of 1g/m².…”