Designing Drugs for Parasitic Diseases of the Developing World

he term "parasite" derives from a classical Greek word that was used to refer to "a guest who comes to dinner and doesn't leave" or "a class of priests who had meals at public expense" (Clitodemus, in Athenaeus Grammaticus, ca.378 B.C.).In modern usage, it refers to eukaryotic organisms that range from single-cell protozoa to complex multicellular worms.The diseases caused by these organisms represent some of the world's greatest health problems.Malaria, for example, currently affects about 500 million people and causes about 3,000 deaths a day-mostly in sub-Saharan Africa [1].Schistosomiasis, caused by Schistosoma spp.(blood fl ukes), affects over 250 million people in the tropical world [2], and a recent meta-analysis showed that the disease is signifi cantly associated with anemia, chronic pain, diarrhea, exercise intolerance, and undernutrition [3].Almost a billion people are infected with the nematode parasites: Ascaris (roundworm), Ancylostoma (hookworm), and Trichuris (whipworm) [2].Why then have so few effective drugs been produced against these diseases?The answer lies primarily in the fact that these are diseases affecting people who are poor and living in poor regions of the world.They represent little or no viable market for the pharmaceutical industry, especially given the market requirements of the recently merged pharmaceutical giants.Given this reality, how can imaginative and effective strategies be developed to meet this challenge?Designing Drugs for Parasitic Diseases of the Developing World James H.