‘Spillover’ diseases are emerging faster than ever before—thanks to humans
History is pockmarked with the scars of past zoonotic outbreaks. What have we learned, why are they increasing, and what can we do to avoid them?
When a dozen merchant ships from the Black Sea docked in Messina, Sicily, in October 1347, they carried a deadly cargo that would change the course of history.
Most of the sailors onboard were dead. The few survivors were covered in oozing, black pustules. Though authorities quickly ordered all people to remain onboard the “death ships,” rats had already disembarked. They and the fleas they carried were infected with Yersinia pestis, the bacterium that causes bubonic plague.
Over the next five years, the Black Death swept Europe, killing 34 to 50 million people—between a third and a half of the population at the time. Scholars at the University of Paris blamed the contagion on a dangerous
