If you don’t know the story of RHDV, it’s probably because you’re not a rabbit. (That’s what the R stands for.) While the decimation of animal populations can make headlines, they’re generally not on the front page. But with new, A-1-worthy diseases now cropping up nearly every year, a team of researchers decided to look again at the RHDV outbreaks. What they found, reported in this week’s Science, may help those seeking to contain the next big human epidemic. Before its sudden spread, RHDV–like many human pathogens–was a mild, under-the-radar virus. In computer models of large, freely mixing populations, it stayed that way. But when it found its way into small populations that occasionally exchanged members, it evolved into a virulent monster. If the same holds for humans, virus hunters should concentrate on sparsely peopled villages in Asia and Africa, precisely where SARS and Ebola arose. And they should get ready for a fight: “There is no moderate virulence,” says biologist Peter Hudson. For animals and humans alike, the worst may be yet to come.
