Accounting for regional transmission variability and the impact of malaria control interventions in Ghana: A population level mathematical modelling approach.
Abstract Background Assessing the effectiveness of malaria control measures in Ghana will require taking transmission dynamics of the disease into account given the influence of climate variability in the region of interest. The impact of preventative interventions on malaria incidence and the prospects of meeting program timelines in Ghana were investigated using mathematical models based on regionally diverse climatic zones. Methods An ordinary non-linear differential equation models with their associated rate parameters were developed incorporating the transitions between various disease compartments for three ecological zones in Ghana. Models were fitted using data from the District Health Information Management System in Ghana from 2008 to 2017 and historical intervention coverage levels. To calibrate the models, Approximate Bayesian Computational sampling approach with a distance based rejection criteria was adopted. A leave-one-out approach was used to validate model parameters and the most sensitive evaluated using a multivariate regression sensitivity analysis. The impact of insecticide treated bed nets and their usage and indoor residual spraying as well as their protective efficacy on the incidence of malaria were simulated at various levels of coverage and protective effectiveness in each ecological zone to investigate the prospects of achieving goals of the malaria control strategy for 2014-2020. Results Increasing the coverage levels of both long lasting insecticide treated bed nets and indoor residual spraying activities without a corresponding increase in their recommended usage does not impact highly on averting predicted incidence of malaria. Improving upon the protective efficacy of long lasting insecticide treated bed nets through proper usage could lead to substantial reductions in the predicted incidence of malaria. Similar results were obtained with indoor residual spraying across all zones.Conclusions Projected goals set in the national strategic plan for malaria control 2014-2020 as well as WHO targets for malaria pre-elimination by 2030 are only likely to be achieved if a substantial improvement in treated bed net usage is achieved coupled with targeted deployment of indoor residual spraying with high community acceptability and efficacy. Key words: model, malaria, interventions, long lasting insecticide bednets, indoor residual spraying