Three researchers have been awarded the Nobel Prize for Medicine for their pioneering work on therapies targeting the parasitic diseases river blindness and malaria.

Retired Merck & Co scientist William Campbell was jointly named the 2015 Nobel Prize winner with Satoshi Omura for the discovery of avermectin, which led to Merck’s development of Mectizan (ivermectin), a treatment for the neglected tropical disease river blindness found in Africa, Latin America and Yemen. 

River blindness is a parasitic infection that can cause intense itching, skin discolouration, rashes, and eye disease that often leads to permanent blindness. It is spread by the bites of infected black flies that breed in rapidly flowing rivers in the affected countries.

Mectizan works by killing the larval worms that live in the subcutaneous tissue of an infected person, and was widely considered a huge treatment advance given its greater effectiveness and improved side effects profile compared to earlier therapies.

Campbell and Omura will share the prize with Youyou Tu for her discoveries on artemisinin - a novel therapy against malaria with roots in Chinese traditional medicine.

Malaria is an infectious mosquito-borne disease causing symptoms such as fever, fatigue and vomiting and in severe cases seizures, coma and death. According to the World Health Organisation, there were 198 million cases of malaria worldwide in 2013, resulting in an estimated 584,000-855,000 deaths, the majority of which (90%) occurred in Africa.

Artemisinin is isolated from the plant Artemisia annua, also known as sweet wormwood, and now forms the basis of the effective treatment against malaria. Since its discovery in the 1970s the drug is credited with having saved millions of lives.