RENEE MONTAGNE, HOST:
Scientists from the United States, Japan and China today won the 2015 Nobel Prize in Physiology or Medicine. The three researchers won for discovering drugs used to treat parasitic diseases that affect millions of people each year. NPR's health correspondent Rob Stein joins us now with the details. Good morning.
ROB STEIN, BYLINE: Good morning, Renee.
MONTAGNE: All right, so names and countries please. Who are the winners?
STEIN: Yes, this year's winners are William C. Campbell - he's at Drew University in Madison, N.J. - Satoshi Omura at the Kitasato University in Japan and Youyou Tu at the China Academy of Traditional Medicine in Beijing.
MONTAGNE: And what exactly were the drugs that they discovered? And these drugs do what?
STEIN: Right. So Campbell and Omura, the American and the Japanese scientist, won for a drug called Avermectin. Now, extracts of this drug are used to treat a variety of parasitic diseases, including something called river blindness, as well as another disease called lymphatic filariasis, which is also known as elephantiasis. Youyou Tu, the Chinese scientist, won for discovering a drug called Artemisinin. That's a drug used to treat a disease a lot more people are probably familiar with - malaria.
MONTAGNE: Well, yes, we are familiar with it, although malaria and those other two diseases don't really affect people here in the U.S., but horribly common in many parts of the world.
STEIN: Oh, yeah, absolutely. The malaria parasite, it's spread by mosquitoes. And the Nobel committee says more than 3.4 billion people around the world are at risk for malaria. And it's still killing about 450,000 people every year. A lot of them are kids. The other diseases, you know, such as river blindness and elephantiasis, are caused by parasitic worms. And they're estimated to afflict one third of the world's population, mostly in southern sub-Saharan Africa, South Asia and Central and South America. Now, river blindness - the parasitic worms infect the cornea of the eye, which is why victims often go blind. In elephantiasis, the parasitic worm infects the lymphatic system, and that causes this chronic swelling that is disabling and terribly disfiguring.
MONTAGNE: And Rob, the Nobels are given often long after - at least sometime after things - drugs are discovered. What about in these cases?
STEIN: Yeah, these are really interesting stories. The discovery of Avermectin started with the Japanese scientist, Satoshi Omura, in the 1970s. He's a microbiologist and an expert in isolating natural products. And he was studying bacteria that live in dirt, actually, that produce natural antibacterial agents. And he was sifting through these bacteria to try to isolate new strains that might produce compounds that might be useful in medicine. And he sent about 50 of the most promising ones to Campbell, the American researcher. He analyzed them and showed that a component of one of them was amazingly effective against this parasite in animals. He purified it and it turned out to be Avermectin, which was then chemically modified to a more effective compound known as Ivermectin, which is the one that's used in people. And the Nobel committee noted that the drug is so effective against both of these diseases that they're on the verge of being eradicated.
And the Chinese scientist Youyou Tu won for discovering the drug for malaria, Artemisinin. Now, she did this as part of a program that Chairman Mao started in the 1960s to find a better way to treat malaria. He was worried about how it was affecting soldiers. So Youyou Tu sifted through traditional Chinese herbal remedies until she found an extract that Chinese herbalists had been using for more than 2,000 years. It's from a plant called Artemisia annua, which is more commonly known as sweet wormwood. She went on to show that it was highly effective at killing the malaria parasite in animals and in humans.
MONTAGNE: Just one last thing - of course, that particular drug has not wiped out malaria.
STEIN: No, not at all. Malaria's still a huge problem in many parts of the world. And there's large international efforts underway to try to eventually - people hope - will eliminate malaria. But still, it's affecting millions of people every year.
MONTAGNE: Well, Rob, thanks very much.
STEIN: Oh, sure. Thank you.
MONTAGNE: Rob Stein, NPR health correspondent, with news that three scientists who discovered drugs for parasitic diseases today won the 2015 Nobel Prize in Physiology or Medicine. Transcript provided by NPR, Copyright NPR.