WHEN it comes to infectious diseases, Ebola and Zika have hogged the headlines of late. But the rise of exotic pathogens does not make more familiar ones less dangerous. Epidemiologists are therefore keeping a close eye on two versions of influenza, known as H5N1 and H7N9 (the “H” and the “N” refer to proteins in the viral coat, and the numbers to particular versions of those proteins). Either of these, they fear, might become pandemic…

This article first appeared in The Economist on 15 November 2016. To continue reading, click here.