History of Ivermectin and the 2015 Nobel Prize

The discovery of ivermectin is widely regarded as one of the most important advances in antiparasitic medicine of the 20th century. The story began in the early 1970s when Japanese microbiologist Satoshi Ōmura collected soil samples in search of new bioactive compounds produced by microorganisms.

One of these samples, taken near a golf course in Kawana, Japan, contained a previously unknown species of bacterium later named Streptomyces avermitilis. Ōmura’s team conducted preliminary screening and sent promising cultures to Merck & Co. in the United States.

At Merck, parasitologist William C. Campbell and his colleagues identified compounds with exceptional activity against parasitic nematodes. These compounds were named avermectins. Through further chemical modification, a safer and more effective derivative was developed and named ivermectin.

Ivermectin was first introduced as a veterinary medicine in 1981. Its potential for human use was later confirmed through clinical studies against onchocerciasis (river blindness). In 1987 it received approval for human use, and Merck established the Mectizan Donation Program to provide the medicine free of charge in endemic areas.

In 2015, Satoshi Ōmura and William C. Campbell were jointly awarded the Nobel Prize in Physiology or Medicine for their discoveries concerning a novel therapy against infections caused by roundworm parasites. Their work has had a lasting impact on global public health.