a | The estimated incidence of malaria worldwide in 2006, stratified per 1, 000 population. Cases in Africa constituted 86% of the global total, Southeast Asia accounted for 9% and the eastern Mediterranean region had 3%. Plasmodium falciparum was found to be responsible for over 75% of the cases in most sub-Saharan African countries but was second to Plasmodium vivax in most countries outside Africa. b | The official first-line antimalarial policy in Africa in 2003 and 2007, demonstrating the dramatic shift from a diversity of first-line antimalarials (typically chloroquine or sulphadoxine–pyrimethamine) towards the adoption of artemisinin-based combination therapies. Part a image is modified, with permission, from REF. © (2008) WHO. Part b image is modified, with permission, from REF. © (2007) UNICEF.