Three scientists were awarded the Nobel Prize in Physiology or Medicine for discovering “therapies that have revolutionized the treatment of some of the most devastating parasitic diseases,” the Nobel Committee announced . William C. Campbell and Satoshi Omura won for developing a new drug, Avermectin, which has radically lowered the incidence of river blindness and lymphatic filariasis (elephantiasis). They shared the prize with Youyou Tu, who discovered Artemisinin, a drug that has significantly reduced death rates from malaria. Parasitic worms, which cause river blindness and lymphatic filariasis, among other diseases, afflict a third of the world’s population, particularly in sub-Saharan Africa, South Asia and Latin America. Malaria, a mosquito-borne disease called by single-cell parasites that invade red blood cells, kills more than 450,000 people a year, most of them children.