Cover Stories

The Nobel Prize 2015 in Physiology or Medicine

By Sarolta Gabulya


[dropcap]T[/dropcap]he 2015 Nobel Prize in Physiology or Medicine has been jointly awarded to William C. Campbell and Satoshi Omura, “for their discoveries concerning a novel therapy against infections caused by roundworm parasites” and Youyou Tu, “for her discoveries concerning a novel therapy against Malaria” stated the announcement, a little after half past 11, at Nobel Forum, Karolinska Institutet.

A major health issue for humankind, which has been around for centuries, is the occurence of parasitic diseases such as lymphatic filariasis, river blindness and malaria. These health issues exist primarily in tropic and subtropic climate zones, affecting many of the world’s poorest regions. The discoveries of this year’s Nobel laureates have lead to the development of revolutionary drugs against these parasite-causing diseases.

River blindness and Lymphatic filariasis (causing lymphedema, elephantiasis and hydrocele) is caused by parasitic worms which infect the body through blackfly or mosquito bites. Parasite larvae, when transferred to the human body, produce embryonic larvae which can either damage the lymphatic system, causing lymphatic filariasis, or migrate to the skin and eye, inducing inflammatory reactions which can cause permanent blindness in the latter (river blindness).

Elephantiasis has infected around 120 million people worldwide, whilst river blindness has infected 18 million people (approximately double the residents of Sweden) of which 270 000 people have consequently gone blind. The initial patient study of Ivermectin showed that a single dose of the drug was efficient to kill all roundworms in patients with river blindness, and today the drug is efficiently used to treat symptoms of river blindness and lymphatic filariasis, including elephantiasis, and other parasitic diseases.

Malaria is caused by parasites transferred to the human body via the bites of infected mosquitoes.  The parasite, called Plasmodium, multiplies in the liver and later infects the red blood cells, causing fever, headache and vomiting. If untreated, the infection can become lethal due to insufficient blood flow to vital organs.

Malaria infects approximately 200 million people each year and according to data from WHO, half of the world’s population has a risk of infection. When Youyou Tu discovered Artemisinin it had already a 100% efficiency against malaria parasites in infected mice and monkeys. Today, artemisinin-base combination therapies (ACTs) are recommended in almost all treatments against malaria.

The discoveries of the 2015 Nobel laureates in Physiology or Medicine have both provided revolutionary therapies for patients suffering from parasitic diseases and have helped individuals and society on many levels. Since the reduction of these disease enable adults to go to work and children to go to school, these vulnerable and poor areas escape poverty by economical and educational improvements. As Hans Forsberg, member of the Nobel Assembly at Karolinska Institutet said, “The global impact of their discovery and the resulting benefit to mankind is immeasurable”.

Nobel Laureates Drawings: Ill. N. Elmehed; Nobel Media AB 2015.

Youyou Tu (China) has been awarded half of the prize for her discoveries of a drug which has significantly decreased the mortality rates amongst malaria patients.

Tu, when seeing the rise of malaria by the late 1960s, turned to traditional herbal medicine to find an effective compound against the disease. Performing a large-scale screening of herbal remedies’ efficacy in Malaria-infected animals, she found that extract from the plant Artemisia annua had a noticeable effect. Inspired by old books describing ancient remedies, she attempted to purify the active component from the plant. The active component, Artemisinin, was found to be effective against Malaria, killing the parasites in the early stages of their development.

William C. Campbell (Ireland) and Satoshi Ōmura (Japan) share half of the prize for their discoveries leading to the new drug Avermectin. Its derivatives have been proven to decrease the incidence of river blindness and lymphatic filariasis along with other similar diseases.

Satoshi Ōmura focused his research on a group of bacteria, called the Streptomyces, which had been discovered to produce agents with antibacterial effect. He did a large-scale culturing and characterization of the Streptomyces and picked out the 50 most promising cultures for further analysis of their effect on microorganisms.

William C. Campbell came across these bacteria cultures and examined their effectivity. He discovered that one of the cultures was distinctively more efficient against parasites in domestic and farm animals. From this culture, the active agent was determined and named Avermectin. This compound was later modified to Ivermectin and tested on humans showing great results in activity against parasite larvae.

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