It’s worth noting that all of our modern plagues are zoonoses coming to us from wild animals. Our other major contagious diseases (from smallpox to TB to measles) mostly came to us from animals that we domesticated beginning ten thousand years ago, which has allowed us time to coevolve with them, to some extent, and develop at least some genetic resistance. These were pathogens that once afflicted the wild ancestors of our cows, pigs, sheep, chickens, and camels. For example, measles appears to have entered our species quite recently, in the sixth century BCE, from a progenitor in cattle that
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