Conquering Malaria

Malaria is the most important of the parasitic diseases of humans, with 107 countries and territories having areas at risk of transmission containing close to 50 percent of the world's population (Hay and others 2004; WHO 2005). More than 3 billion people live in malarious areas and the disease causes between 1 million and 3 million deaths each year (Breman, Alilio, and Mills 2004; Snow and others 2003). Recent estimates of the global falciparum malaria morbidity burden have increased the number to 515 million cases, with Africa suffering the vast majority of this toll (Snow and others 2005). In addition, almost 5 billion clinical episodes resembling malaria occur in endemic areas annually, with more than 90 percent of this burden occurring in Africa (Breman 2001; Breman, Alilio, and Mills 2004; Carter and Mendis 2002; Snow and others 1999, 2003; Snow, Trape, and Marsh 2001).

The disease has resurged in many parts of the tropics, and nonmalarious countries face continual danger from importation. Contributing to this resurgence are the increasing problems of Plasmodium falciparum resistance to drugs and of the Anopheles vectors' resistance to insecticides. The recent findings that insecticide-treated nets (ITNs) are extremely cost-effective in preventing malaria and overall deaths and that intermittent preventive therapy (IPT) (treatment doses given during periods of vulnerability) is effective for protecting pregnant women and their fetuses, along with the discovery of new drugs (artemisinins) and their use in combination with other antimalarials and promising vaccine trials, have given great impetus to the battle against this scourge (Alonso and others 2004; Armstrong-Schellenberg and others 2001; Lengeler 2004; Newman and others 2003; Yeung and others 2004).