Combining indoor residual spraying and insecticide-treated nets for malaria control in Africa: a review of possible outcomes and an outline of suggestions for the future

Abstract

Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) are currently the preferred methods of malaria vector control. In many cases, these methods are used together in the same households, especially to suppress transmission in holoendemic and hyperendemic scenarios. Though widespread, there has been limited evidence suggesting that such co-application confers greater protective benefits than either ITNs or IRS when used alone. Since both methods are insecticide-based and intradomicilliary, this article hypothesises that outcomes of their combination would depend on effects of the candidate active ingredients on mosquitoes that enter or those that attempt to enter houses. It is suggested here that enhanced household level protection can be achieved if the ITNs and IRS have divergent yet complementary properties, e.g. highly deterrent IRS compounds coupled with highly toxic ITNs. To ensure that the problem of insecticide resistance is avoided, the ITNs and IRS products should preferably be of different insecticide classes, e.g. pyrethroid-based nets combined with organophosphate or carbamate based IRS. The overall community benefits would however depend also on other factors such as proportion of people covered by the interventions and the behaviour of vector species. This article concludes by emphasizing the need for basic and operational research, including mathematical modelling to evaluate IRS/ITN combinations in comparison to IRS alone or ITNs alone.

Impact of long-lasting insecticide-incorporated screens onColorado potato beetle and plum curculio

“…LLISs are now promoted as a key method to fight malaria and its vector (Atkinson et al, 2009). Although the efficacy and potential of LLISs for wide applications is undisputed, their use has mostly been limited to controlling household pests and insect vectors such as mosquitoes and flies (Baume and Marin, 2008;Okumu and Moore, 2011).…”

Efficacy of indoor residual spraying with dichlorodiphenyltrichloroethane against malaria in Gambian communities with high usage of long-lasting insecticidal mosquito nets: a cluster-randomised controlled trial

“…Today universal coverage with either LLIN or IRS is the major malaria prevention strategy and in many settings where IRS is used, LLIN are already deployed. Whilst the individual protection afforded by LLIN 3 and IRS 4 is well known, the joint impact of these interventions is poorly understood 5,6 .…”

Installation of insecticide-treated durable wall lining: evaluation of attachment materials and product durability under field conditions

“…While both interventions have considerably reduced disease morbidity when used alone [4,5] and in combination [6][7][8], problems of sustainability, increasing insecticide resistance and operational constraints now undermine movements towards malaria elimination [9][10][11]. In areas of stable or high transmission in sub-Saharan Africa, the infrastructure required to support large-scale, recurrent IRS campaigns of indefinite duration is not feasible [12].…”