Thomas Goetz

He took stool samples from everyone willing to let him.

And soon he had definitively identified hookworms as a cause of widespread malaise.

Based on his poop studies, he estimated that around 40% of Southerners, whites and blacks, almost always poor, they carried hookworms.

He called these parasites Nekator americanus, which translates as American murderer.

This was a misnomer, actually.

People rarely die of hookworm infections.

But hookworms did make daily life much, much worse.

At the time, this was the first years of the 20th century, to be poor in the South meant almost no sanitation.

No running water, no toilets, often no outhouses.

People pooped, well, wherever, in the woods, behind bushes.

And most poor people went without shoes, children especially.

It was just easier that way.

Shoes cost money.

These were ideal conditions for the hookworm to prosper.

Let's start in the dirt.

Hookworm larvae live in the soil and burrow through to reach their target, human feet, where they quickly slip into the pores of bare skin.

This might cause a rash.

It was called ground itch.

But the worm is in.

The larvae, which are super tiny, scarcely visible to the human eye, they then wriggle their way into blood vessels and enter the bloodstream.