Nobel Prize recognises discoveries in parasitic diseases

Posted: 5 October 2015 | Victoria White

The Nobel Prize for Physiology or Medicine has been split this year to recognise work that has revolutionised the treatment of some parasitic diseases…

The Nobel Prize for Physiology or Medicine has been split this year to recognise work that has revolutionised the treatment of some of the most devastating parasitic diseases.

William C. Campbell and Satoshi Ōmura have been awarded the Nobel Prize for their discoveries concerning a novel therapy against infections caused by roundworm parasites.

Parasitic worms (helminths) are estimated to afflict one third of the world’s population and are particularly prevalent in subSaharan Africa, South Asia and Central and South America. River Blindness and Lymphatic Filariasis are two diseases caused by parasitic worms. As the name implies, River Blindness (Onchocerciasis) ultimately leads to blindness, because of chronic inflammation in the cornea. Lymphatic Filariasis, afflicting more than 100 million people, causes chronic swelling and leads to life-long stigmatizing and disabling clinical symptoms, including Elephantiasis (Lymphedema) and Scrotal Hydrocele.

Satoshi Ōmura’s work focused on a group of bacteria, Streptomyces, which lives in the soil and was known to produce a plethora of agents with antibacterial activities. Ōmura isolated new strains of Streptomyces from soil samples and successfully cultured them in the laboratory. From many thousand different cultures, he selected about 50 of the most promising, with the intent that they would be further analysed for their activity against harmful microorganisms.

William C. Campbell acquired Ōmura’s Streptomyces cultures and explored their efficacy. Campbell showed that a component from one of the cultures was remarkably efficient against parasites in domestic and farm animals. The bioactive agent was purified and named Avermectin, which was subsequently chemically modified to a more effective compound called Ivermectin. Ivermectin was later tested in humans with parasitic infections and effectively killed parasite larvae (microfilaria). 

Today Ivermectin is used in all parts of the world that are plagued by parasitic diseases. Ivermectin is highly effective against a range of parasites and is freely available across the globe. The Nobel Assembly commented that 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.

Youyou Tu awarded Nobel Prize for discoveries concerning Malaria therapy Artemisinin

Youyou Tu has also been awarded the Nobel Prize for her work that lead to the discovery of Artemisinin, a drug that has significantly reduced the mortality rates for patients suffering from Malaria.

Malaria was traditionally treated by chloroquine or quinine, but with declining success. By the late 1960s, efforts to eradicate Malaria had failed and the disease was on the rise. At that time, Youyou Tu turned to traditional herbal medicine to tackle the challenge of developing novel Malaria therapies. From a large-scale screen of herbal remedies in Malaria-infected animals, an extract from the plant Artemisia annua emerged as an interesting candidate. Tu successfully extracted the active component from Artemisia annua and was the first to show that this component, later called Artemisinin, was highly effective against the Malaria parasite, both in infected animals and in humans.

Now, 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 that Campbell, Ōmura and Tu have made have transformed the treatment of parasitic diseases.

Celia Holland, a professor at the university where Professor Campbell graduated from, Trinity College Dublin, commented, “All of us in zoology are immensely proud of Professor Campbell for winning the Nobel prize. Bill’s development the drug Ivermectin  has had a massive impact on the world, saving millions from diseases caused by parasites. This award to Bill underscores the impact that zoologists can have upon the world by understanding how animals, parasites and microbes interact and by using that knowledge to develop new ways to tackle human and animal diseases. As a zoologist, Bill was certainly ahead of his time, his research underlines the importance of the very modern concept of ‘One Health’ which promotes an understanding of parasite ecology and its interactions with wild and domestic animals, humans and their environment. This integrated view of zoology is very much in keeping with the training that we give to zoologists today.”

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