The Story Of Ivermectin

isglobal  |   What do penicillin, aspirin and ivermectin have in common? Apart from the fact that they rhyme, all three belong to a very select group of drugs that can claim to have had the “greatest beneficial impact on the health and well-being of humanity”.

They have at least two other things in common: all three were found in nature and all three led to a Nobel prize. Aspirin is derived from salicin, a compound found in a variety of plants such as willow trees. Its use was first mentioned by Hippocrates in 400 BC, but was isolated only in 1829 as salicylic acid and synthesised some years later as acetylsalicylic acid. The discovery of the mechanisms underlying aspirin’s effects gave Sir John Vane the Nobel prize in 1982. Penicillin was isolated from mold that grew by accident on a Petri dish in Alexander Fleming’s laboratory. Its discovery changed the course of medicine, and earned Fleming the Nobel prize in 1945, which he shared with Howard Florey and Ernst Chain.

And this brings us to ivermectin- not likely a drug you will have in your first-aid kit, like aspirin or penicillin, but definitely a drug that has improved the lives of millions of people since its discovery in 1975.

The story of how ivermectin was discovered is quite incredible. In the late 1960s, Satoshi Ōmura, a microbiologist at Tokyo’s Kitasako Institute, was hunting for new antibacterial compounds and started to collect thousands of soil samples from around Japan. He cultured bacteria from the samples, screened the cultures for medicinal potential, and sent them 10,000 km away to Merck Research Labs in New Jersey, where his collaborator, William Campbell, tested their effect against parasitic worms affecting livestock and other animals. One culture, derived from a soil sample collected near a golf course southwest of Tokyo, was remarkably effective against worms. The bacterium in the culture was a new species, and was baptised Streptomyces avermictilis. The active component, named avermectin, was chemically modified to increase its activity and its safety. The new compound, called ivermectin, was commercialised as a product for animal health in 1981 and soon became a top-selling veterinary drug in the world. Remarkably, despite decades of searching, S. avermictilis remains the only source of avermectin ever found.