A little over one hundred years ago, a novel virus emerged from an unknown animal reservoir and seeded itself silently in settlements around the world. Then, in the closing months of World War I, as if from nowhere, the infection exploded in multiple countries and continents at more or less the same time. From Boston to Cape Town, and London to Mumbai, the “Spanish flu,” so-called because the first widely reported outbreak occurred in Madrid in May 1918, swept like wildfire through cities and communities both large and small
