Scientific Background Avermectin and Artemisinin - Revolutionary Therapies against Parasitic Diseases

The 2015 Nobel Prize in Physiology or Medicine is awarded with one half jointly to Dr. William C. Campbell and Professor Satoshi Ōmura for their discoveries concerning a novel therapy against infections caused by roundworm parasites and the other half to Professor Youyou Tu for her discoveries concerning a novel therapy against Malaria. Parasitic diseases have long plagued humankind and constitute a major global health problem. River Blindness (Onchocerciasis) is a disease that can ultimately lead to irreversible blindness. Lymphatic Filariasis causes chronic swelling and leads to life-long stigmatizing and disabling clinical symptoms, known as Elephantiasis (Lymphedema) and Scrotal Hydrocele. Both these diseases are caused by parasitic worms. Malaria, a mosquito-borne disease, is caused by single-cell parasites (Plasmodium), which invade red blood cells, causing fever, and in severe cases brain inflammation and death. Collectively, these diseases affect the world’s most vulnerable citizens, particularly in sub-Saharan Africa, South Asia and South and Central America, and represent a huge barrier towards improving human health and welfare. The 2015 Nobel Laureates have radically altered the treatment of these devastating diseases. Satoshi Ōmura searched for bioactive substances from the soil and isolated a new microorganism (Streptomyces avermitilis) with remarkable properties. William C. Campbell identified the antiparasitic activity of Ōmura’s microbial culture and characterized the effective component, named Avermectin, against a variety of parasitic worms in domestic and farm animals. Today the Avermectin-derivative Ivermectin is on good way to eradicate River Blindness and Lymphatic Filariasis. Youyou Tu turned to traditional herbal medicine and ancient literature in her quest for a therapy against Malaria. She identified an extract from the plant Artemisia annua that inhibited parasite growth and isolated the active component (Artemisinin) that was highly effective against malaria. Today, Artemisinin-based drug combination therapy has profoundly reduced the incidence and mortality of malaria, saving millions of lives worldwide. Campbell, Ōmura and Tu have transformed the treatment of parasitic diseases. The global impact of their discoveries and benefit to mankind is immeasurable. Microbes and Parasites A Major Health Problem