Effects of insecticide-treated bednets and curtains (ITNs) or of indoor residual spraying (IRS) on malaria transmission have usually been studied by comparing areas with high coverage with others with no or minimal interventions. The long-term dynamics of transmission effects are often not considered and most trials are of too short a duration to address them. Field observations suggest that effects on parasite prevalence (and hence on human-mosquito transmission) may take several years to reach equilibrium, and hence that such analyses underestimate the long-term effects of interventions. In the context of other projects we are developing new dynamic models for malaria transmission and epidemiology. We now propose to apply these to estimating long-term effects of ITNs and IRS, as well as Anopheles larval control interventions in programme settings across sub-Saharan Africa.
