STOCKHOLM — A Chinese scientist who turned to ancient texts to discover a powerful malaria drug shared the Nobel Prize in medicine on Monday with American and Japanese researchers whose discoveries have raised hopes of eliminating other tropical diseases.
Tu Youyou — the first-ever Chinese medicine laureate — will share the 8 million Swedish kronor (about $960,000) award with Japanese microbiologist Satoshi Omura and William Campbell, an Irish-born U.S. scientist.
Tu was cited for discovering artemisinin, a drug that’s now the primary treatment against malaria, saving millions of lives worldwide. Inspired by Chinese traditional medicine, she made her discovery while working on a malaria project for the Chinese military.
Omura and Campbell discovered another drug, avermectin, whose derivatives have helped fight river blindness and lymphatic filariasis. Those diseases are caused by parasitic worms and affect millions of people in Africa and Asia.
The Nobel committee said the winners, who are all in their 80s and made their breakthroughs in the 1970s and ‘80s, had given humankind powerful tools to combat debilitating diseases.
‘‘The consequences in terms of improved human health and reduced suffering are immeasurable,’’ the committee said.
Campbell, 85, is a research fellow emeritus at Drew University in Madison, New Jersey. He told the AP he made his main discovery in 1975 while working at pharmaceutical company Merck.
‘‘It was a great team effort by the people at Merck and Company,’’ said Campbell, who now lives in North Andover, Mass. He said the award came as a ‘‘huge surprise.’’
He learned that he had won when awakened by a phone call from a wire service reporter at about 6 a.m., his wife, Mary, said in a telephone interview.
“Does one ever expect to win a Nobel Prize?,” she said. “It was a shock. And a very happy shock.”
She added that her husband knew that the drug ivermectin “had been very effective in human medicine and veterinary medicine, and my husband with his team at Merck, had been the innovators who made this treatment possible in Africa and has saved millions of people from blindness.”
In 2013, Colombia became the first country in the world to eliminate the transmission of river blindness (onchocerciasis), according to the Pan American Health Organization. That was accomplished with Merck’s MECTIZAN Donation Program and The Carter Center-sponsored Onchocerciasis Elimination Program. (Mectizan is Merck’s trade name for ivermectin, the compound Campbell discovered. Last year Ecuador became the second.
Merck’s donation program began in October 1987, when the company announced that it would donate Mectizan “to all who need it for as long as necessary until onchocerciasis is eliminated as a public health problem,” the company said when it announced the Ecuador milestone. Merck estimates that the program reaches more than 150 million people annually.
In Latin America, since 1989, more than 13 million treatments of Mectizan have been delivered by local health workers and non-governmental organizations, according to Merck.
Merck has donated more than 1 billion treatments to people in 28 countries in Africa, six in Latin America, and in Yemen. Although the World Health Organization has verified only Colombia and Ecuador as having have eliminated onchocerciasis, Guatemala and Mexico were able to stop transmission in 2011 and are awaiting WHO verification. In Africa, health officials believe that onchocerciasis transmission has been stopped in large swaths of Uganda, as well as pocket in Mali and Sudan.
In 1998, Merck began donating Mectizan for the treatment of lymphatic filariasis (elephantiasis) as well as onchocerciasis in Africa and Yemen.
Omura, 80, is a professor emeritus at Kitasato University in Japan and is from the central prefecture of Yamanashi. He wondered whether he deserved the prize.
‘‘I have learned so much from microorganisms and I have depended on them, so I would much rather give the prize to microorganisms,’’ Omura told Japanese broadcaster NHK.
Working in the 1970s, Omura isolated new strains of Streptomyces bacteria and cultured them so that they could be analyzed for their impact against harmful microorganisms, the Nobel committee said.
Omura said the crucial strain was found in a soil sample from a golf course near Tokyo. He said he always carries around a plastic bag in his wallet so he can collect soil samples.
Campbell showed that one of those cultures was remarkably efficient against parasites in animals, the committee said. The bioactive agent was purified and modified to a compound that effectively killed parasitic larvae, leading to the discovery of new class of drugs.
Today they are considered a highly effective treatment against river blindness and lymphatic filariasis, the committee said.
River blindness is an eye and skin disease that ultimately leads to blindness. About 90 percent of the disease occurs in Africa, according to the World Health Organization.
Lymphatic filariasis can lead to swelling of the limbs and genitals, called elephantiasis, and it’s primarily a threat in Africa and Asia. WHO says 120 million people are infected with the disease, with about 40 million disfigured and incapacitated.
Tu, 84, is chief professor at the China Academy of Traditional Chinese Medicine. As a junior researcher, she was recruited by the Chinese government to work on a military project in 1969 to find malaria drugs.
She turned to herbal medicine to discover a new malarial agent in an extract from the sweet wormwood plant. The agent, artemisinin (pronounced ar-tuh-MIHS’-ihn-ihn), was highly effective against malaria, a disease that was on the rise in the 1960s, the committee said.
Malaria is a mosquito-borne disease that still kills around 500,000 people a year, mostly in Africa, despite efforts to control it.
Colin Sutherland, reader in parasitology at London School of Hygiene and Tropical Medicine, said that the impact of artemesinin had been profound. It’s so widely used across the world that there’s a risk of resistance problems.
‘‘The writing is on the wall already. We probably have about five to 10 years of effective use of artemesinins before resistance becomes a problem,’’ he said.
WHO says artemisinin resistance has already been confirmed in Cambodia, Laos, Myanmar, Thailand and Vietnam.
There have been several previous Nobel Prizes for malaria research, including the 1902 award to British army surgeon Ronald Ross, who discovered the disease is transmitted by mosquitos.
The last time a Chinese citizen won a Nobel was in 2012, when Mo Yan got the literature award. But China has been yearning for a Nobel Prize in science. This was the first Nobel Prize given to a Chinese scientist for work carried out within China.
‘‘This is indeed a glorious moment,’’ said Li Chenjian, a vice provost at prestigious Peking University. ‘‘This also is an acknowledgement to the traditional Chinese medicine, for the work began with herbal medicine.’’
Stephen Ward, deputy director of Liverpool School of Tropical Medicine, said the prize confirms that Chinese scientists ‘‘did fantastic work in the 1960s even when they were effectively ignored by the rest of the world.’’
The medicine award was the first Nobel Prize to be announced. The winners of the physics, chemistry and peace prizes are set to be announced later this week. The economics prize will be announced next Monday. No date has been set yet for the literature prize, but it is expected to be announced on Thursday.
Besides the cash prize, each winner also gets a diploma and a gold medal at the annual award ceremony on Dec. 10, the anniversary of the death of prize founder Alfred Nobel.
Associated Press writers Malcolm Ritter in New York, Maria Cheng in London, Didi Tang in Beijing, Mari Yamaguchi in Tokyo, and Geoff Mulvihill in Haddonfield, New Jersey, contributed to this report.