Over the past 50 years, more than 300 infectious diseases have either newly emerged or re-emerged into territory where they’ve never been seen before. A few weeks after the end of the Ebola crisis, the Zika virus is just the latest example. Each health crisis yields promises of new approaches and learning from our mistakes. And yet, we continue to fight global contagions in a similarly reactive, incremental fashion.
By Sonia Shah
Journalist, author of “Pandemic” from which this piece is adapted
Over the past 50 years, more than 300 infectious diseases have either newly emerged or re-emerged into territory where they’ve never been seen before. The Zika virus, a once-obscure pathogen from the forests of Uganda now rampaging across the Americas, is just the latest example. It joins a legion of other diseases that have similarly broken out of earlier constraints, including Ebola in West Africa, Middle East Respiratory Syndrome (MERS) in the Middle East, and novel avian influenzas in Asia, one of which hit the U.S poultry industry last spring, causing the biggest animal disease epidemic in U.S. history.
When such pathogens spread like a wave across continents and global populations, they cause pandemics, from the Greek pan (“all”) and demos (“people”). Given the number of pathogens in our midst with pandemic-causing biological capacities, pandemics themselves are relatively rare. In modern history, only a few pathogens have been able to cause them: Yersinia pestis, which causes bubonic plague; variola, which causes smallpox; influenza A; HIV; and cholera.
Cholera is one of the history’s most successful pandemic-causing pathogens. The first cholera pandemic began in the Sundarbans in present-day Bangladesh in 1817. Since then, it has ravaged the planet in no fewer than seven pandemics, the latest of which is currently smoldering just a few hundred miles off the coast of Florida, in Haiti.
Cholera first perfected the art of pandemics by exploiting the rapid changes in transportation, trade, and demography unleashed by the dawn of the factory age. New, fast-moving transatlantic clipper ships and sailing packets, which moved millions of Europeans into North America, brought cholera to the New World in 1832. Thanks to the opening of the Erie Canal in 1825, the bacterial pathogen easily spread throughout the country, including into the canal’s southern terminus, New York City, which suffered repeated cholera epidemics over the course of decades.