Today's Kinetoplastida form a diverse order of flagellated protozoans that have evolved from an ancient lineage, rooted near the base of the eukaryotic tree. The disease caused by some species of the Order Kinetoplastida have always plagued mankind, and today most are at least as prevalent as they have ever been. Kinetoplastid parasites cause disease in humans, animals and plants, severely affecting human health and retarding agriculture development in less developed countries. Sleeping sickness (caused by pathogenic subspecies ofTrypanosoma brucei), Chagas disease (caused byTrypanosoma cruzi) and the Leishmaniases (caused byLeishmania spp) are the major human diseases caused by kinetoplastids. According to the World Health Organization "sleeping sickness" affects more than 60 million men, women and children in 36 countries of sub-Saharan Africa, most of which are among the least developed countries in the world. In many of these countries sleeping sickness is currently epidemic, re-emerging in some as a greater cause of morbidity than evenHIV/AIDS.T. cruzicurrently infects 14 million people in Latin America. It is the agent ofChagas disease, the leading infectious cardiomyopathy in the world. Theleishmaniasesand the suffering they cause threaten 350 million women, men and children in 88 countries around the world, 72 of which are developing countries. In addition to their medical importance kinetoplastid parasites also cost developing nations millions of dollars in lost agricultural revenues, since other kinetoplastids are pestilences that strike agricultural produce from crops, to fish to cattle.