Three scientists won the Nobel Prize for Medicine Monday, October 5, 2015, for their groundbreaking work on drugs used to prevent and treat parasitic diseases. Japan’s Satoshi Omura, China’s Youyou Tu, and Ireland’s William C. Campbell all played a part in the development of this new drug.

According to CNN, avermectin, a main component of this drug, was discovered by Campbell and Omura. This derivative is used to treat river blindness and lymphatic filariasis, also known as elephantiasis. Artemisinin, discovered by Tu, can effectively fight malaria and its use has led to a major decline in deaths from malaria.

Ivermectin, derived from avermectin, is used across the globe to fight roundworm. Artemisnin, used to kill malaria in its early stages, was discovered by Tu among traditional herbal medicine practices.

Half of the prize was awarded to Omura and Campbell, while the other half was presented to Tu. The Nobel Assembly said of Omura and Campbell’s discovery, “These two discoveries have provided humankind with powerful new means to combat these debilitating diseases that affect hundreds of millions of people annually. The consequences in terms of improved human health and reduced suffering are immeasurable.”

The assembly said of Tu’s discovery, “Artemisinin represents a new class of antimalarial agents that rapidly kill the Malaria parasites at an early stage of their development, which explains its unprecedented potency in the treatment of severe malaria.”

The assembly also noted how the treatment of river blindness and lymphatic filarisis is so successful that the diseases have almost been eradicated.