STOCKHOLM — A trio of scientists earned the 2015 Nobel prize for medicine on Monday for unlocking revolutionary treatments for malaria and roundworm, helping to roll back two parasitic diseases that blight millions of lives.

Tu Youyou of China won half of the award for her work on artemisinin, a drug based on Chinese herbal medicine, the Nobel jury announced.

She is the first Chinese woman to win a Nobel science prize, and only the 12th to win in medicine among the 210 laureates honoured since 1901.

Irish-born William Campbell and Satoshi Omura of Japan shared the other half for an anti-roundworm treatment dubbed avermectin, derived from soil-dwelling bacteria.

“These two discoveries have provided humankind with powerful new means to combat these debilitating diseases that affect hundreds of millions of people annually,” the Nobel committee said. “The consequences in terms of improved human health and reduced suffering are immeasurable.”

Ms Tu, 84, has been chief professor at the China Academy of Traditional Chinese Medicine since 2000. She conducted research in the 1970s, at the height of the Cultural Revolution, that led to the discovery of artemisinin, which has slashed the number of malaria deaths.

The treatment is based on traditional medicine — a herb called sweet wormwood or Artemisia annua.

Artemisinin-based drugs have been the standard combination for treating malaria since the mosquito-transferred plasmodium parasite developed resistance to other drug types such as chloroquine.

According to the World Health Organisation, there were about 198-million malaria infections in 2013 and 584,000 deaths — most of them African children.

Social media users in China saw the award as a source of national pride for the country.

“So proud, so proud, Chinese people are awesome,” read a post on Sina Weibo, a Chinese version of Twitter.

“Nobel Prize, good. More international achievements recognised globally represent China’s rise,” said another.

The other half of the prize honoured Mr Omura and Mr Campbell for “a new class of drugs with extraordinary efficacy against parasitic diseases”, the Nobel statement said.

Registered drugs derived from avermectin “have radically lowered” the incidence of river blindness and elephantiasis, both caused by parasitic worms, it added.

River blindness, also known as onchocerciasis, is caused by a worm transmitted to humans through the bites of infected blackflies. Its symptoms include disfiguring skin conditions and visual impairment, including permanent blindness.

More than 99% of people who are affected by it live in Africa.