Crowding and Disease Virulence

This Element is an excerpt from Germs, Genes, & Civilization: How Epidemics Shaped Who We Are Today (9780137019960) by David P. Clark. Available in print and digital formats.

Why it's wishful thinking to believe that diseases will eventually evolve into milder forms-and what the hard truth means for humanity.

Earlier thinking held that, given time, all diseases would adapt, to become no worse than measles. Virulent diseases were newcomers, not yet adapted to biological détente with their human hosts. This wishful thinking has obvious marketing appeal-but it ignores the ugly side of both evolution and human history.