Disease, the Wild Card of History
Disease has to be counted as one of the wild cards of history, an unforeseen factor that can, in a matter of days or weeks, undo the deterministic sure thing or humble the conquering momentum. History is full of examples. There was the plague that ravaged Athens for more than a year and led to its capture and the dismantling of its empire in 404 [B.C.E.]. An outbreak of dysentery weakened the Prussian force invading France in 1792 [C.E.] and helped to convince their leaders to turn back after losing the battle of Valmy, thus saving the French Revolution. The ravages of typhus and dysentery are the hidden story of Napoleon’s calamity in Russia. The war-vectored influenza epidemic of 1918 [C.E.] may not have changed immediate outcomes, but how many potential reputations did we lose to it—people who might have made a difference to their generation? Bacteria and viruses may thus redirect vast impersonal forces in human societies, and they can also become forces in their own right.
— Robert Cowley (editor), What If?, p. 2
