The global distribution of clinical episodes of Plasmodium falciparum malaria


Interest in mapping the global distribution of malaria is motivated by a need to define populations at risk for appropriate resource allocation1,2 and to provide a robust framework for evaluating its global economic impact3,4. Comparison of older5,6,7 and more recent1,4 malaria maps shows how the disease has been geographically restricted, but it remains entrenched in poor areas of the world with climates suitable for transmission. Here we provide an empirical approach to estimating the number of clinical events caused by Plasmodium falciparum worldwide, by using a combination of epidemiological, geographical and demographic data. We estimate that there were 515 (range 300–660) million episodes of clinical P. falciparum malaria in 2002. These global estimates are up to 50% higher than those reported by the World Health Organization (WHO) and 200% higher for areas outside Africa, reflecting the WHO's reliance upon passive national reporting for these countries. Without an informed understanding of the cartography of malaria risk, the global extent of clinical disease caused by P. falciparum will continue to be underestimated.

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Figure 1: Annual clinical incidence of P. falciparum per 1,000 population according to hypoendemic (n = 39), mesoendemic (n = 25) and combined hyperendemic and holoendemic (n = 8) conditions.
Figure 2: P. falciparum endemicity distribution within the global limits of risk.


  1. 1

    Hay, S. I., Guerra, C. A., Tatem, A. J., Noor, A. M. & Snow, R. W. The global distribution and population at risk of malaria: past, present and future. Lancet Infect. Dis. 4, 327–336 (2004)

    Article  Google Scholar 

  2. 2

    Snow, R. W., Marsh, K. & le Sueur, D. The need for maps of transmission intensity to guide malaria control in Africa. Parasitol. Today 12, 455–457 (1996)

    Article  Google Scholar 

  3. 3

    Gallup, J. L. & Sachs, J. D. The economic burden of malaria. Am. J. Trop. Med. Hyg. 64, 85–96 (2001)

    CAS  Article  Google Scholar 

  4. 4

    Kiszewski, A. et al. A global index representing the stability of malaria transmission. Am. J. Trop. Med. Hyg. 70, 486–498 (2004)

    Article  Google Scholar 

  5. 5

    Russell, P. F. World-wide malaria distribution, prevalence and control. Am. J. Trop. Med. Hyg. 5, 937–956 (1956)

    CAS  Article  Google Scholar 

  6. 6

    Lysenko, A. J. & Semashko, I. N. in Itogi Nauki: Medicinskaja Geografija (ed. Lebedew, A. W.) 25–146 (Academy of Sciences, Moscow, 1968)

    Google Scholar 

  7. 7

    Lysenko, A. J. & Beljaev, A. E. An analysis of the geographical distribution of Plasmodium ovale . Bull. World Health Organ. 40, 383–394 (1969)

    CAS  PubMed  PubMed Central  Google Scholar 

  8. 8

    Murray, C. J. L. & Lopez, A. D. Mortality by cause for eight regions of the world: global burden of disease study. Lancet 349, 1269–1276 (1997)

    CAS  Article  Google Scholar 

  9. 9

    World Health Organization. The World Health Report 1999: Making a Difference (World Health Organization, Geneva, 1999)

    Google Scholar 

  10. 10

    Snow, R. W., Craig, M. H., Deichmann, U. & Marsh, K. Estimating mortality, morbidity and disability due to malaria among Africa's non-pregnant population. Bull. W.H.O. 77, 624–640 (1999)

    CAS  PubMed  Google Scholar 

  11. 11

    Carter, R. & Mendis, K. N. Evolutionary and historical aspects of the burden of malaria. Clin. Microbiol. Rev. 15, 564–594 (2002)

    Article  Google Scholar 

  12. 12

    Mendis, K., Sina, L. J., Marchensini, P. & Carter, R. The neglected burden of Plasmodium vivax malaria. Am. J. Trop. Med. Hyg. 64, 97–106 (2001)

    CAS  Article  Google Scholar 

  13. 13

    Murray, C. J. & Lopez, A. D. Global Health Statistics: a Compendium of Incidence, Prevalence and Mortality Estimates for over 200 Countries (Harvard School of Public Health, Boston/World Health Organization, Geneva, 1996)

    Google Scholar 

  14. 14

    International Network for the Continuous Demographic Evaluation of Populations and Their Health in Developing Countries.

  15. 15

    Snow, R. W. et al. Relation between severe malaria morbidity in children and level of Plasmodium falciparum transmission in Africa. Lancet 349, 1650–1654 (1997)

    CAS  Article  Google Scholar 

  16. 16

    Prusty, S. K. R. & Das, B. S. Low incidence of the severe complications of malaria and absence of malaria-specific mortality, in Tensa, Sundergarh district, Orissa State, India, an area hyper-endemic for malaria. Ann. Trop. Med. Parasit. 95, 133–140 (2001)

    CAS  Article  Google Scholar 

  17. 17

    Maitland, K. et al. Absence of malaria-specific mortality in children in an area of hyperendemic malaria. Trans. R. Soc. Trop. Med. Hyg. 91, 562–566 (1997)

    CAS  Article  Google Scholar 

  18. 18

    Alles, H. K., Mendis, K. N. & Carter, R. Malaria mortality rates in South Asia and in Africa: implications for malaria control. Parasitol. Today 14, 369–375 (1998)

    CAS  Article  Google Scholar 

  19. 19

    Mayfong, M., Pukrittayakamee, S., Newton, P. N. & White, N. J. Mixed species malaria infections in humans. Trends Parasitol. 20, 233–240 (2004)

    Article  Google Scholar 

  20. 20

    United Nations Development Programme. Human Development Report 2003. Millennium Development Goals: a Compact among Nations to End Human Poverty (Oxford Univ. Press, Oxford, 2003)

    Google Scholar 

  21. 21

    Metselaar, D. & Van Theil, P. H. Classification of malaria. Trop. Geogr. Med. 11, 157–161 (1959)

    Google Scholar 

  22. 22

    World Health Organization. International Travel and Health. Situation as on 1 January 2003 (World Health Organization, Geneva, 2003)

    Google Scholar 

  23. 23

    International Association for Medical Assistance to Travellers. World malaria risk chart (including geographical distribution of principal vectors, geographical distribution of P. falciparum malaria, areas where Plasmodium falciparum is resistant to chloroquine and guidelines for suppressive medication by country). Status as of 15 March 2004.

  24. 24

    Hay, S. I., Guerra, C. A., Tatem, A. J., Atkinson, P. M. & Snow, R. W. Urbanization, malaria transmission and disease burden in Africa. Nature Rev. Microbiol. 3, 81–90 (2005)

    CAS  Article  Google Scholar 

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This research was funded by the Wellcome Trust, UK. Part of the work on mapping population risk distributions was funded by the World Health Organization Roll Back Malaria Department. The World Health Organization/RBM Department Monitoring and Evaluation Team and staff from WHO regional offices provided passive case detection data, the WHO Evidence for Information and Policy Department provided SALB data and the WHO Public Health Mapping Group provided other geographical boundary files. We thank K. Marsh, D. Forster, C. Macintosh, K. Maitland and D. Rogers for comments on earlier drafts of the manuscript, D. Balk and G. Yetman for supplying alpha versions of GPW 3.0, and A. Tatem for the urban extractions. R.W.S. is a Wellcome Trust Senior Research Fellow and acknowledges the support of the Kenyan Medical Research Institute (KEMRI). S.I.H. is funded by a Research Career Development Fellowship from the Wellcome Trust. C.A.G. is partially funded by the Fundación para la Ciencia y Tecnología (FUNDACYT).

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Correspondence to Robert W. Snow.

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Competing interests

Since completing this research S.I.H., C.A.G. and R.W.S. have undertaken an agreement to perform work for which remuneration was received, with RBM/WHO to estimate global, regional, national, and sub-national population at risk of various levels of malaria endemicity, by age group and parasite type in countries outside Africa (see Supplementary Information B).

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This file contains information on malaria morbidity (part A) and populations at risk (part B). (DOC 114 kb)

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Snow, R., Guerra, C., Noor, A. et al. The global distribution of clinical episodes of Plasmodium falciparum malaria. Nature 434, 214–217 (2005).

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