It’s strange that we now see America threatened by a plague. Because without plague, America, as we know it, wouldn’t exist. It may have been the most devastating epidemic in the history of humankind — surpassing in its mortality rates any before or since, including the Black Death in the Europe of the mid-14th century. Smallpox arrived in America with the first Europeans and went on, with several other imported diseases, to wipe out up to 90 percent of the Native population in a relatively short amount of time — millions and maybe tens of millions died.