Drug resistance in malaria.

Half of the world's population live in regions where malaria is still endemic and about 2 million are killed by the disease every year. There is an exponential increase in the number of non-immune travellers who visit such areas and thousands develop malaria after they return home. The few drugs currently available for the prevention or treatment of malaria are discussed and the history of the emergence of multiple drug resistance in the malignant tertian parasite, Plasmodium falciparum, is traced from its origins in the late 1950s to the present time when it is found in the endemic regions of all continents. These are indications that chloroquine resistance is beginning to appear now also in P. vivax in the Southwest Pacific. The few new drugs under development and the uncertain future that they face are discussed.