The fight against infectious diseases is still an uphill battle

It was barely more than half a century ago that the Nobel Prize–winning virologist Sir Frank Macfarlane Burnet mused about the demise of contagions. “To write about infectious disease,” he wrote in 1962, “is almost to write of something that has passed into history.”

If only. In the past several decades, over 300 infectious pathogens have either newly emerged or emerged in new places, causing a steady drumbeat of outbreaks and global pandemic scares.

Over the course of 2016, their exploits reached a crescendo. Just as the unprecedented outbreak of Ebola in West Africa was collapsing in early 2016, the World Health Organization declared Zika virus, newly erupted in the Americas, an international public health emergency. What would balloon into the largest outbreak of yellow fever in Angola in 30 years had just begun. A few months later, scientists reported