[Current Trend of Drug Development for Neglected Tropical Diseases (NTDs)]

EBOLA hemorrhagic fever, a typical emerging infectious disease, began in December 2013 in the southern part of Guinea, and killed more than 11000 people by the end of June, 2015. In addition to emerging/re-emerging diseases and the 3 major infectious diseases i.e. HIV/AIDS, tuberculosis and malaria, neglected tropical diseases (NTDs) have recently become important tropical diseases of the poor. It is remarkable that Japan succeeded in the eradication of malaria and other tropical diseases, which include lymphatic filariasis and schistosomiasis. However, despite these achievements, it is important to sustain our efforts when we consider global health. This review highlights the significance of elimination and/or control of NTDs, and then introduces the current situation of drug development activities in Japan, which are aimed towards combating tropical infectious diseases. They include studies on a novel drug target, the "mitochondrial NADH-fumarate reductase system (Fumarate respiration)" composed of complex I, rhodoquinone and complex II, which plays an important role in the anaerobic energy metabolism of many helminths such as Ascaris suum. An additional interesting finding highlighted herein is that ascofuranone, a recently developed anti-African trypanosome drug, shows specific inhibition of fumarate respiration in Echinococcus multilocularis mitochondria.