How viruses shape the world

HUMANS THINK of themselves as the world’s apex predators. Hence the silence of sabre-tooth tigers, the absence of moas from New Zealand and the long list of endangered megafauna. But SARS-CoV-2 shows how people can also end up as prey. Viruses have caused a litany of modern pandemics, from covid-19, to HIV/AIDS to the influenza outbreak in 1918-20, which killed many more people than the first world war. Before that, the colonisation of the Americas by Europeans was abetted—and perhaps made possible—by epidemics of smallpox, measles and influenza brought unwittingly by the invaders, which annihilated many of the original inhabitants.