Nobel Prize 2015 – Protecting People against Parasites!

The 2015 Nobel Prize in Physiology or Medicine has been awarded to scientists whose research has led to therapies that have saved hundreds of millions of people around the world from parasitic diseases that can otherwise cause disability and death.

William C. Campbell and Satoshi Ōmura shared one half of the award “for their discoveries concerning a novel therapy against infections caused by roundworm parasites”, while Youyou Tu was awarded the other half “for her discoveries concerning a novel therapy against Malaria”.

Portraits of the winners of the Nobel medicine prize, shown on a screen at the ceremony in Stockholm. Photograph: Jonathan Nackstrand/AFP/Getty Images

In the press release announcing the award the Nobel Assembly at the Karolinska Institute highlighted the impact of the therapies that were developed thanks to the work done by these three scientists, Avermectin in the case of William C. Campbell and Satoshi Ōmura, and Artemisinin in the case of Youyou Tu.

The discoveries of Avermectin and Artemisinin have fundamentally changed the treatment of parasitic diseases. Today the Avermectin-derivative Ivermectin is used in all parts of the world that are plagued by parasitic diseases. Ivermectin is highly effective against a range of parasites, has limited side effects and is freely available across the globe. The importance of Ivermectin for improving the health and wellbeing of millions of individuals with River Blindness and Lymphatic Filariasis, primarily in the poorest regions of the world, is immeasurable. Treatment is so successful that these diseases are on the verge of eradication, which would be a major feat in the medical history of humankind. Malaria infects close to 200 million individuals yearly. Artemisinin is used in all Malaria-ridden parts of the world. When used in combination therapy, it is estimated to reduce mortality from Malaria by more than 20% overall and by more than 30% in children.

For Africa alone, this means that more than 100 000 lives are saved each year.

The discoveries of Avermectin and Artemisinin have revolutionized therapy for patients suffering from devastating parasitic diseases. Campbell, Ōmura and Tu have transformed the treatment of parasitic diseases. The global impact of their discoveries and the resulting benefit to mankind are immeasurable.

Animal research played a key part in the development of these therapies, as the Nobel Prize press release has pointed out.

Image: NobelPrize.org

In the case of Avermectin, after  Satoshi Ōmura had identified a series of bacterial cultures that produced a variety of antimicrobial agents, including the bacteria Streptomyces avermitilis which  showed promise against parasitic roundworm infection in mice, in 1979 William C. Campbell and colleagues identified a particular component produced by S. avermitilis called Avermectin B1a which had a broad efficiency against roundworm infections in a wide range of domesticated animal species, including cattle, sheep, dogs and chickens. Following this the team developed a modified form of Avermectin B1a known as Ivermectin, which was entered into clinical trials following positive tests in animal models of parasitic infection, and has since gone on to become a key treatment for parasitic infections – particularly the nematode worm infections that cause River Blindness and  Lymphatic Filariasis (the extreme manifestation of which is known as elephantitis) – and is on the World Health Organization’s list of Essential Medicines.

Image: NobelPrize.org

Ivermectin, and other members of the Avermectin family of therapies, are also widely used in veterinary practice, and their development and use is a good example of the One Health principle in action. You can learn more about the discovery of the Avermectins and Artemisinins in the advanced material Avermectin and Artemisinin – Revolutionary Therapies against Parasitic Diseases produced by the Nobel Assembly.

In 2011 we took a look at Professor Youyou Tu’s research that led to the development of Artemisinin therapy for malaria, and the key role played by mouse models of malaria infection,  in a post entitled “George is OK: Thank the men who stare down microscopes!”

While the news reports don’t state which drugs Cloony took to beat malaria, It is most likely that he was treated with artemisinin-based combination therapies (ACTs), which became available in the late 1990s and are now in widespread use.  If that is the case, he has benefited from mouse studies done in China the late 1960s and early 1970s when over 100 traditional herbal remedies were screened in a rodent model of malaria for anti-malarial activity (1). Eventually “Project 523” scored a hit when Professor Tu Youyou identified an extract of the plant qinghao, scientific name Artemisia annua, which had good anti-malarial activity, leading to the development of the artemisinin-based anti-malarials which have become the first-line treatment for malaria in the past decade.

We congratulate this years Nobel laureates in Physiology or Medicine, their research has improved the lives of hundreds of millions of people across the world over the past 3 decades, and will continue to do so. We hope that their success continues to inspire scientists around the world to rise to current and future public health challenges!

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