Nobel prize for river blindness drug discoverers

Two scientists have been awarded the Nobel prize for their discovery of a drug being used to eradicate river blindness.

William C. Campbell from Ireland and Japan’s Satoshi Ōmura were each awarded a quarter share in the 2015 Nobel Prize in Physiology or Medicine for their work which led to an effective anti-parasitic drug ivermectin, which is helping to eradicate river blindness and elephantisis.

River blindness, or onchocerciasis, is a disease caused by a parasitic roundworm. Infected flies, which breed near fast-flowing water where many people bath and wash, spread the parasite when they bite humans. Once inside their human hosts, the worms produce larvae which move to the skin’s surface, causing itching and lesions. The inflammation and lesions can occur on the cornea, which can lead to permanent blindness if left untreated.

The condition mainly affects people in rural parts of 31 African countries, but also latin America and Yemen. Elephantitis, or lymphatic filiarisis, is caused by a similar parasite, but is spread by mosquitos.

The path towards a treatment for the condition began when Professor Ōmura, a microbiologist and now emeritus professor at Kitasato University, started to isolate soil bacteria samples from the local area in the search for new medical compounds in the 1970s. One of these strains found near a local golf course, Streptomyces avermitilis, was the source of the compound avermectin.

Professor Campbell, a parasitologist based at Drew University in New Jersey, later discovered that the compound produced by S.avermitilis was effective in killing parasitic round worms in animals. His work would eventually lead to the production of ivermectin, a derivative of avermectin made by pharmaceutical company Merck.

The drug is such an effective treatment that it forms the core strategy in eliminating the neglected tropical diseases, with clinical trials in patients with river blindness showing a single dose was sufficient to kill all of the parasites.

Professors Campbell and Ōmura share the Nobel Prize with Professor Tu Youyou of the Chinese Academy of Medical Sciences, who was awarded a half share of the accolade for her discovery of the anti-malarial drug artemisinin. Professor Youyou isolated the compound from sweet wormwood, which is used in Chinese traditional medicine, and is China’s first Nobel laureate in medicine.

In a statement released earlier this week, the Nobel Assembly at the Karolinka Institute in Sweden, said: “These two discoveries have provided humankind with powerful new means to combat these debilitating diseases that affect hundreds of millions of people annually.”

The assembly added: “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.”

Image credit: Adam Baker