'Silent Killer' May Be Disease of the Affluent

From an early age, the indigenous Shuar people of the Ecuadorian Amazon are exposed to an army of parasites, viruses, and other microbes. But if children survive to adulthood—no guarantee, given that they're three times more likely to die before the age of 5 than children in the United States and Canada—they seem to end up with more efficient immune systems than people living in industrialized nations. That's the conclusion of a new study, which adds weight to the idea that early exposure to pathogens confers long-term health benefits.

https://www.sciencemag.org/news/2012/05/silent-killer-may-be-disease-affluent