3 scientists share Nobel for discovering drugs to kill parasites

Jan Andersson, Juleen Zierath and Hans Forssberg, members of the Karolinska Institute Nobel committee, talk to media at a press conference in Stockholm, Monday Oct. 5, 2015. (Fredrik Sandberg / TT)

STOCKHOLM -- The Nobel prize in medicine went Monday to three scientists hailed as "heroes in the truest sense of the word" for saving millions of lives with the creation of the world's leading malaria-fighting drug and another that has nearly wiped out two devastating tropical diseases.

Tu Youyou -- the first-ever Chinese medicine laureate -- turned to ancient texts to produce artemesinin, a drug that is now the top treatment for malaria. Inspired by traditional Chinese medicine, Tu discovered that a compound from the wormwood plant was highly effective against the malaria parasite, while working on a project for the Chinese military during the Cultural Revolution.

She 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.

Omura and Campbell created the drug avermectin, whose derivatives have nearly rid the planet of river blindness and lymphatic filarisis, diseases caused by parasitic worms and spread by mosquitos and flies. They affect millions of people in Africa, Latin America and Asia, leaving sufferers blind or disfigured and often unable to work.

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: "The consequences in terms of improved human health and reduced suffering are immeasurable," the committee said.

The Carter Center called the three laureates "heroes in the truest sense of the word, saving lives through medicine."

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," said Campbell, who now lives in North Andover, Massachusetts. He said the award came as a "huge surprise."

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, named avermectin and modified to a compound that effectively killed parasitic larvae, leading to the creation of a new class of drugs.

Today, its derivative ivermectin is considered a highly effective preventive treatment against river blindness and lymphatic filariasis, the committee said.

"(Ivermectin) reduces the number of parasites in the blood so that when a mosquito bites someone, it cannot transmit the disease to someone else," said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston. He said mass distribution campaigns have given out ivermectin for free to 450 million people in efforts to eliminate both river blindness and lymphatic filariasis.

Hotez said that in parts of Africa, adult sufferers of river blindness are often led around with a stick by a young child. Until ivermectin came along, Hotez said there was no way to effectively prevent the disease.

Tu, 84, is a researcher at the China Academy of Chinese Medical Sciences.

As a junior researcher, she was recruited by Chairman Mao's 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, a reader in parasitology at London School of Hygiene and Tropical Medicine, said that the impact of artemesinin has been profound and changed nearly every country's malaria treatment protocol.

Still, 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 that 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.

Cheng reported from London. Associated Press writers Malin Rising in Stockholm, Malcolm Ritter in New York, Didi Tang in Beijing, Mari Yamaguchi in Tokyo, and Geoff Mulvihill in Haddonfield, New Jersey, contributed to this report