The changing risk of Plasmodium falciparum malaria infection in Africa: 2000-10: a spatial and temporal analysis of transmission intensity

Background Over a decade ago, the Roll Back Malaria Partnership was launched, and since then there has been unprecedented investment in malaria control. We examined the change in malaria transmission intensity during the period 2000-10 in Africa. Methods We assembled a geocoded and community Plasmodium falciparum parasite rate standardised to the age group 2-10 years (PfP R2-10) database from across 49 endemic countries and territories in Africa from surveys undertaken since 1980. The data were used within a Bayesian space-time geostatistical framework to predict PfP R2-10 in 2000 and 2010 at a 1 x 1 km spatial resolution. Population distribution maps at the same spatial resolution were used to compute populations at risk by endemicity class and estimate population-adjusted PfP R2-10 (P A PfP R2-10) for each of the 44 countries for which predictions were possible for each year. Findings Between 2000 and 2010, the population in hyperendemic (>50% to 75% PfP R2-10) or holoendemic (>75% PfP R2-10) areas decreased from 218.6 million (34.4%) of 635.7 million to 183.5 million (22.5%) of 815.7 million across 44 malaria-endemic countries. 280.1 million (34.3%) people lived in areas of mesoendemic transmission (>10% to 50% PfP R2-10) in 2010 compared with 178.6 million (28.1%) in 2000. Population in areas of unstable or very low transmission (<5% PfP R2-10) increased from 131.7 million people (20.7%) in 2000 to 219.0 million (26.8%) in 2010. An estimated 217.6 million people, or 26.7% of the 2010 population, lived in areas where transmission had reduced by at least one PfP R2-10 endemicity class. 40 countries showed a reduction in national mean P A PfP R2-10. Only ten countries contributed 87.1% of the population living in areas of hyperendemic or holoendemic transmission in 2010. Interpretation Substantial reductions in malaria transmission have been achieved in endemic countries in Africa over the period 2000-10. However, 57% of the population in 2010 continued to live in areas where transmission remains moderate to intense and global support to sustain and accelerate the reduction of transmission must remain a priority.