Thomas Goetz

But when the baby worms, the larvae, get into the eye, a more intense immune reaction can cause inflammation, and that leads to blindness.

River blindness itself is rarely deadly to individuals, but it can prove fatal to a family or to a village because blindness often comes to men and women in their prime productive years.

Sons or daughters must drop out of the workforce to care for a blind parent.

Marriages and parenthood are less common.

Eventually, young people flee the village.

For decades, there was little to be done for Onchocerciasis.

As many as 20 million people were infected with the parasite worldwide, and hundreds of thousands were blinded or had impaired vision because of the disease.

In the 1970s, the World Bank began using DDT and other insecticides to kill black fly populations in West Africa.

This worked in places, but it was terrifically dangerous to the environment and to human health.

And then in 1981, a new drug appeared that might work for river blindness and for other parasitic diseases too, including hookworm.

This was ivermectin.

And we'll get into that after a break in part two.

Welcome back to Drug Story.

This is part two, The Prescription, where we explore the creation and the use of a drug to treat disease.

And today's drug is, of course, ivermectin.

The creation of ivermectin begins, of all places, on a golf course south of Tokyo, Japan, in 1973.

On the edge of the course, looking east over Sagami Bay, a young scientist named Satoshi Omura was digging up dirt.

Now, at the time, it was well known that soil, dirt, was full of life and full of microbes.

In any patch of earth, a war is going on, with various bacteria producing chemical agents to kill off rival bacteria in the quest for food and survival.

Since 1943, it was known that some of those microbes could be isolated and turned into medicines.