We live in a biologically complex world, which is populated not only by humans and other large animals, but also by a plethora of other organisms, some of which are harmful or deadly to us.

A variety of parasites cause disease. A medically important group are the parasitic worms (helminths), which are estimated to afflict one third of the world’s population and are particularly prevalent in sub-Saharan 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 (Figure 1).

Malaria has been with humankind for as long as we know. It is a mosquito-borne disease caused by single-cell parasites, which invade red blood cells, causing fever, and in severe cases brain damage and death. More than 3.4 billion of the world’s most vulnerable citizens are at risk of contracting Malaria, and each year it claims more than 450 000 lives, predominantly among children (Figure 1).

From bacteria and plants to novel anti-parasite therapies

After decades of limited progress in developing durable therapies for parasitic diseases, the discoveries by this year’s Laureates radically changed the situation.

Satoshi Ōmura, a Japanese microbiologist and expert in isolating natural products, focused on a group of bacteria, Streptomyces, which lives in the soil and was known to produce a plethora of agents with antibacterial activities (including Streptomycin discovered by Selman Waksman, Nobel Prize 1952). Equipped with extraordinary skills in developing unique methods for large-scale culturing and characterization of these bacteria, Ōmura isolated new strains of Streptomyces from soil samples and successfully cultured them in the laboratory.