MAPPING MALARIA11 March 2005 More than half a billion cases of deadly Plasmodium falciparum malaria occurred in 2002 – suggesting that malaria is an even bigger problem than first thought. |
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Professor Bob Snow and his team, at the University of Oxford and the Kenya Medical Research Institute–Wellcome Trust Laboratories in Nairobi, have used a variety of methods to calculate the likely number of cases of malaria in a single year, 2002. Their estimate of 515 million clinical episodes of P. falciparum suggests that tackling malaria will require even greater attention than governments and health agencies might have anticipated.
The latest estimates used contemporary and historical epidemiological, geographical and demographic information to model where people live, the likelihood that they become infected, and their susceptibility to developing the disease. The models also made use of new methods in geographic information systems and data from Earth-orbiting satellites.
According to the new analysis, more than two-thirds of cases occurred in Africa, where P. falciparum malaria mostly affects children under five. But far more cases than previously thought take place outside Africa, with nearly 25 per cent of worldwide cases occurring in South-east Asia and the Western Pacific.
Although the numbers remain estimates, they provide a more accurate picture of the likely global burden of malaria – important if the disease is to receive the public health priority it deserves.