Malaria, river blindness, elephantiasis tropica - these diseases kill or disable people worldwide. It is thanks to this year's Nobel Prize laureates that they can be cured.
Once every few years, you don't really have to explain why a discovery is worth a Nobel prize for Medicine, for example if a discovery has already saved millions of lives. That is true for this year's Nobel Prize in Medicine.
The Nobel prize committee has awarded one half of the Nobel Prize in Medicine or Physiology 2015 to Irish researcher William C. Campbell and Japanese researcher Satoshi Omura for "a novel therapy against infections caused by roundworm parasites." The other half of the prize goes to the Chinese scientist Youyou Tu "for her discovery concerning a novel therapy against malaria."
Insect-borne roundworms and malaria parasites infect millions of people worldwide every year. Especially people in developing countries with inadequate health systems suffer from them. But the three Nobel Prize winners set out to find drugs against these diseases - and were successful.
Youyou Tu discovered the substance artemisinin which kills malaria parasites.
Today it is the drug of choice to treat malaria patients, according Jürgen May from the Bernhard Nocht Institute for Tropical Medicine in Hamburg.
"The success in fighting malaria we had over the last years wouldn't have been possible without artemisinin," May told DW.
Youyou Tu from the China Academy of Traditional Chinese Medicine had studied both Chinese and Western medicine. She had seen many children in the final stages of malaria. That made a big impression on her. She wanted to find a drug to help these children - no matter what.
"The work was the top priority, so I was certainly willing to sacrifice my personal life," she told the magazine "The New Scientist" in 2011.
She even left her 4-year old daughter in the care of a local nursery to be able to do her work in the malaria endemic Hainan province in the South of China.
An herbal remedy in traditional Chinese Medicine was known to cure malaria. Youyou Tu extracted the active component from the plant Artemisia annua and showed that it killed malaria parasites.
While the substance is still extracted from plants, the pharmaceutical industry also produces tons of it biotechnologically and chemically every year.
"The discovery of artemisinin was a major improvement," malaria researcher Michael Ramharter from Vienna Medical University told DW. "It kills malaria parasites very fast; the patients are quickly free from fever and any other symptoms."
Artemisinin kills malaria parasites in several development stages - even extremely young ones. According to Ramharter, not many anti-malaria drugs can do this. The substance also has few side effects.
When given to patients, artemisinin is combined with one or several other anti-malaria drugs. It should never be given alone, the World Health Organisation warns, to make sure malaria parasites don't develop a resistance against the drug.
"With these combination therapies, a parasite would have to become resistant against several substances at the same time to survive," Ramharter explains. That is extremely unlikely.
It would be a "significant setback in the fight against malaria" if the parasites became resistant against artemisinin, Ramharter adds. Unfortunately, that's exactly what is beginning to happen in parts of Thailand, Myanmar, Cambodia and Laos. "In some parts, the effectiveness of artemisinin is dropping," Jürgen May said. "It takes longer for the patients to get rid of the parasites. And that is a warning sign."
Parasites that make you blind
The other half of the Nobel Prize for Medicine or Physiology goes to William C. Campbell and Satoshi Omura. They also developed a very efficient drug: It kills parasitic roundworms that reproduce inside the human body.
Roundworms can cause river blindness due to chronic inflammation in the cornea and elephantiasis tropica, which leads to swollen arms, legs and genitals. Both are so-called neglected tropical diseases and affect millions of people in developing countries.
When Omura heard that he was awarded the Nobel prize, he was surprised. "I learned so many things from the microorganisms," he told the Japanese TV station NHK. "It would be more appropriate to award the prize to them."
Omura isolated bacteria from the soil and reproduced them in his lab. William C Campbell later extracted the substance avermectin from these bacteria.
Avermectin was chemically modified to ivermectin - a drug that kills parasite larvae. It can cure river blindness and elephantiasis tropica and thus prevent people from turning blind or living with swollen body parts for the rest of their lives.
Eradicating diseases with drugs
William C. Campbell worked with pharmaceutical company "MSD Sharp and Dohme." This corporation still produces and markets ivermectin.
Medical director Kristian Löbner is very proud that the Nobel Prize was awarded to the developers of the drug, he told DW. "All my colleagues here haven't stopped smiling since we heard the news."
As part of the company's charity program, "MSD Sharp and Dohme" has already donated three billion pills containing ivermectin to developing countries, and plans to continue donating until river blindness is completely eliminated.
Thanks to the drug, river blindness has already been eradicated in three countries: Mexico, Colombia and Ecuador. "In 26 African countries we are about to eradicate the disease," Löbner says.
Tropical disease specialist Jürgen May concludes: "An efficient drug is an important, even essential part to eradicate such diseases." But he also emphasizes that improving those countries' public health systems is just as fundamental.