Mapping the global extent of malaria in 2005

Abstract

Guidelines for travellers on malaria chemoprophylaxis, the altitude limits of dominant vector species, climate suitability for malaria transmission and human population density thresholds have been used to map the crude spatial limits of Plasmodium falciparum and Plasmodium vivax transmission on a global scale. These maps suggest that 2.510 and 2.596 billion people were at possible risk of transmission of P. falciparum and P. vivax, respectively, in 2005. Globally, 75 per cent of humans who are exposed to P. falciparum risk live in only ten countries.

Figure 1

Global distribution of P. falciparum and P. vivax in 2005. (a) Distribution of P. falciparum. (b) Distribution of P. vivax. Several sources of information on malaria risk (notably ITHGs on malaria chemoprophylaxis, altitude limits for dominant vectors, climate limits for malaria transmission and human population density thresholds) have been combined in a geographic information system to generate these maps. See the step-by-step guide in the main text for a full description of the methods used to derive these limits.

Figure 2

Cartograms of the PAR of malaria from P. falciparum and P. vivax in 2005. (a) P. falciparum risk. (b) P. vivax risk. In these cartograms, the area is distorted in proportion to the national PAR of malaria [2]. These maps are useful global indicators and represent broad spatial patterns, but it should be remembered that the risk of developing disease, disability or death from malaria infection is specific to parasite and region [3], and the exact implications of the regional differences will be examined in more detail in future work.