Radiolab

Your Friendly Neighborhood Hookworms

For most of human history, hookworms and their parasitic kin were ubiquitous companions to our species, and the immune system evolved in their presence. The provocative idea at the heart of helminth therapy is that without these old enemies to fight, our immune systems grow restless and turn on us instead.

Radiolab

Your Friendly Neighborhood Hookworms

For most of human history, people were infected with helminths — parasitic worms — as a matter of course. It's only in the past century or so, in wealthy industrialized nations, that we've largely eliminated them. And it's in those same places that allergies, asthma, and autoimmune diseases have skyrocketed.

Radiolab

Your Friendly Neighborhood Hookworms

For most of human history, hookworms and other parasitic worms were ubiquitous companions to our species. It was only in the twentieth century that sanitation campaigns, shoes, and antiparasitic drugs largely eliminated them from wealthy countries — and it was shortly after that elimination that rates of allergies, autoimmune diseases, and inflammatory bowel conditions began their dramatic rise.

Radiolab

Your Friendly Neighborhood Hookworms

For most of human history, hookworms and other parasitic worms were ubiquitous companions of Homo sapiens, and our immune systems co-evolved with them over millions of years. The idea is that without these old friends, our immune systems become unbalanced — overly aggressive, prone to attacking the body itself or harmless substances like pollen.

Radiolab

Your Friendly Neighborhood Hookworms

For most of human history, hookworms and other parasitic worms were ubiquitous companions — so much so that the human immune system may have evolved to expect their presence. Without them, the theory goes, our immune systems can become overactive, mistakenly attacking the body itself or reacting to harmless substances like pollen or peanuts.

Radiolab

Your Friendly Neighborhood Hookworms

For most of human history, people were infected with intestinal worms. The worms, in turn, evolved to modulate their hosts' immune responses — keeping inflammation in check so the host could survive and the worms could keep living inside them. The modern, wormy-free immune system, the hypothesis goes, never got that memo and remains primed to overreact.

Radiolab

Your Friendly Neighborhood Hookworms

For most of human history, hookworms and other parasitic worms were ubiquitous companions to our species, and our immune systems evolved in their presence. The idea, known as the hygiene hypothesis or 'old friends' hypothesis, is that the absence of these organisms in the modern developed world has left our immune systems without the regulatory signals they evolved to expect — potentially contributing to the rise of allergies, autoimmune diseases, and inflammatory conditions.

Radiolab

Your Friendly Neighborhood Hookworms

For most of human history, intestinal worms were ubiquitous companions. Only in the twentieth century did sanitation campaigns and deworming programs scrub them from the bodies of people in wealthy nations. But some researchers now suspect that in eliminating these parasites, we may have also dismantled part of our immune system's essential operating instructions.