Immune: A Journey Into the Mysterious System That Keeps You Alive

by Philipp Dettmer

In evolutionary terms, humans in developed countries in the last few hundred years or so suddenly lost their parasitic wormy guests. The advent of soap and hygiene and the clear separation of poop and drinking water destroyed the life cycles of most of the worms that were living within us. The remaining worms were exiled by drugs and modern medicine. Which left our immune system suddenly without the enemy that had kept it down a notch for millions of years. And so it might be that our immune system still operates under the assumption that worms are making it weaker and that it needs to be more aggressive as a counterbalance. If this general idea is true it might explain a lot of diseases caused by too-aggressive immune systems in people without worms, mostly allergies and inflammatory disease. And not only that—the lack of worms leaves a whole bunch of our cells without the enemy they were made to fight on a regular basis. So the idea makes sense that without wormy stimulation, these weapons just found new targets.