The Nobel Prize for Medicine and Physiology has been jointly awarded to Youyou Tu (the first ever Chinese recipient of a Nobel Prize in this category) for discovering the malarial medicine Artemisinin, and to William C. Campbell and Satoshi Ōmura, for their pioneering work in developing a major parasitic round worm disease drug, Ivermectin.
These affordable (and in one case freely-available) medicines have treated around 3.4 billion people worldwide combined. Contraction of infectious diseases such as Malaria, Lymphatic filariasis (Elephantiasis) and River Blindness is often lethal due to the expense of healthcare in less well-developed regions where the parasite vectors (mosquitoes, black flies etc.) which transmit them are most prevalent. These 3 researchers have therefore been jointly-awarded the Nobel Prize for Medicine in recognition for their huge contribution to the battle against parasitic disease.
Satoshi Ōmura is a Japanese microbiologist who is jointly responsible for the discovery of the parasite drug Ivermectin. This is a highly potent drug against roundworm diseases such as River Blindness (caused by the parasite Ochocerca volvulus which is transmitted to the host by the bite of black flies from the Simulidae family) and Lymphatic Filariasis (extreme odema in peripheral tissues caused by the parasite Wucheria bancrofti).