Fine-scale spatial mapping of urban malaria prevalence for microstratification in an urban area of Ghana.

BACKGROUND: Malaria is a focal disease and more localized in low endemic areas. The disease is increasingly becoming a concern in urban areas in most sub-Saharan African countries. The growing threats of Anopheles stephensi and insecticide resistance magnify this concern and hamper elimination efforts. It is, therefore, imperative to identify areas, within urban settings, of high-risk of malaria to help better target interventions. METHODS: In this study, a set of environmental, climatic, and urban covariates were combined with observed data from a malaria prevalence study in Ghana and geospatial methods used to predict malaria risk in the Greater Accra Region of Ghana. Georeferenced data from 12,371 surveyed children aged between 6 months and 10 years were included in the analysis. The probability of malaria prevalence exceeding 10% (exceedance probability) in the Region was further calculated. RESULTS: Predicted malaria prevalence in this age group ranged from 0 to 49%. Satellite-driven data on tasselled cap brightness, enhanced vegetation index and a combination of urban covariates were predictive of malaria prevalence in the study region. A map that quantified the probability of malaria prevalence exceeding 10% was produced. CONCLUSIONS: The malaria prevalence and exceedance probability maps showed areas within the districts earmarked for malaria elimination that have high malaria risk. It is anticipated that this study results can support decision making at both national and subnational levels on deployment of strategic malaria interventions.