Estimates of Deaths from Malaria

Deaths are not well counted in much of the world, and the situation is worst where people are poorest—which is where malaria takes its greatest toll. This has begun to change—Snow and colleagues (2003) date recognition of the importance of reliable estimates to the World Health Organization’s (WHO’s) Global Burden of Disease program of the early 1990s—but the figures available are still approximate.

Some 50 years ago, Leonard Bruce-Chwatt estimated the annual African death toll from malaria at one million. The figure was an extrapolation to the continent based on the civil registration of deaths in Lagos in 1950 (Bruce-Chwatt, 1952). Other numbers have been produced since then—between 0.5 million and 2 million deaths per year—using a variety of more and less evidence-based methods (Sturchler, 1989; Greenwood, 1990; WHO, 1996; Schwartlander, 1997). The most plausible current estimates come from Snow and colleagues, and their work on the Burden of Malaria in Africa (BOMA) project (Snow et al., 2003), which builds on the MARA (Mapping Malaria Risk in Africa) risk mapping, as well as mining of a wide range of other data sources. Their best estimate is 1,144,572 deaths attributable directly to malaria in Africa in the year 2000 (Table 7-1).

WHO’s most recent estimate of malaria deaths is similar—a worldwide total of 1,124,000 deaths due directly to malaria in 2001, of which about 970,000 would have been in Africa (WHO, 2002). The estimate also includes about 90,000 malaria deaths in Southeast Asia, 56,000 in the Eastern Mediterranean region, 11,000 in the Western Pacific, and about 1,000 in the Americas. While in the same overall range, the estimates do differ in their distribution among age groups: Snow and colleagues figures suggest that about 65 percent of deaths among children under 5, and the corresponding figure from WHO is much higher at 86 percent.

Estimates of Malaria Cases

There are no direct counts of the number of cases of malaria that occur each year. A very wide range of estimates has been made, using a variety of definitions. The lack of precision is problematic for this report, because an estimate of how many courses of malaria treatment are used is needed to estimate how much a global ACT subsidy will cost. The number of cases and the number of treatments are not the same but are related.

Malaria cases may be overestimated because few cases are definitively diagnosed before treatment (whether prescribed or self-selected), so quite a large number of fevers that are not malaria may be counted as such. The number also may be underestimated because people may get no treatment, either through choice or economic default, and in any case, episodes of malaria are not kept track of formally anywhere.



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