Malaria as a reemerging disease.

Malaria is a clear example of a reemerging disease. The annual number of cases (incidence) fell sharply 30-35 years ago as the result of a malaria eradication campaign (1, 2). At that time, malaria was eliminated from Europe, most Asian regions of the USSR, the United States, and most of the Caribbean (3). However, it was not eradicated in Southeast Asia, South America, or Africa, and has reemerged in Sri Lanka, Madagascar, and elsewhere (3). Thus, the incidence of malaria today is greater than 40 years ago and is increasing because of antimalarial drug resistance (4, 5), insecticide resistance (6), and the effects of civil strife—dislocation of susceptible refugee populations from nonendemic areas to areas with malaria transmission (7, 8). The incidence of malaria complications (morbidity) and deaths (mortality) is likewise increasing because of drug resistance (9). These changes also reflect the failure thus far of alternative control strategies, such as vaccine development. The net result is that the increasing morbidity and mortality of malaria affect not only the health of the developing world, but also (prevent) its economic development. This review begins by examining the two major reasons that the malaria eradication campaign was unsuccessful, antimalarial drug resistance and insecticide resistance. It then examines alternative malaria control strategies such as the development of antimalarial agents effective against drug-resistant parasites, of bednets and curtains impregnated with pyrethroid insecticides, and of malaria vaccines, concluding with a discussion of