Malaria transmission is influenced by climate, land use and deliberate interventions. Recent declines have been observed in malaria transmission. Here we show that the African continent has witnessed a long-term decline in the prevalence of Plasmodium falciparum from 40% prevalence in the period 1900–1929 to 24% prevalence in the period 2010–2015, a trend that has been interrupted by periods of rapidly increasing or decreasing transmission. The cycles and trend over the past 115 years are inconsistent with explanations in terms of climate or deliberate intervention alone. Previous global initiatives have had minor impacts on malaria transmission, and a historically unprecedented decline has been observed since 2000. However, there has been little change in the high transmission belt that covers large parts of West and Central Africa. Previous efforts to model the changing patterns of P. falciparum transmission intensity in Africa have been limited to the past 15 years1,2 or have used maps drawn from historical expert opinions3. We provide quantitative data, from 50,424 surveys at 36,966 geocoded locations, that covers 115 years of malaria history in sub-Saharan Africa; inferring from these data to future trends, we would expect continued reductions in malaria transmission, punctuated with resurgences.
We thank Á. Munoz and M. Thompson for advice on long-term climate data; M. Coetzee and J. Hemmingway for details of emerging insecticide resistance; E. Okiro, M. English and D. Zurovac for comments on earlier drafts of the paper; and the individuals and institutions who have helped to assemble malaria data from across Africa over the past 21 years (see Supplementary Information 5). The present study was supported by the International Development Research Centre, Canada (1996–1998) and the Wellcome Trust, UK (1996–1997: 048335) through the Mapping Malaria Risk in Africa (MARA/ARMA) project, and the Wellcome Trust through the Malaria Atlas Project (MAP) in 2005 (034694) and funding to R.W.S. as part of his Principal Fellowship since 2007 (079080 and 103602). A.M.N. acknowledges support from the Wellcome Trust as an Intermediary Fellow (095127); R.W.S., D.K., J.M., P.A., C.W.M., P.B. and A.M.N. acknowledge the support of the Wellcome Trust for the Kenya Major Overseas Programme (077092 and 203077). R.W.S. is grateful to the Department for International Development (UK) for their support of Strengthening the Use of Data for Malaria Decision Making in Africa (DFID Programme Code 203155), which provided support to D.K. and J.M.
Extended data figures
Source data for GIS shape files of historical endemicity. This file provides margins and polygons of prediction of malaria at its historical extent.
Source data for GIS shape files of changing margins of malaria risk in Africa. This file shows how margins of transmission of malaria changed from 1900 to 2015.