With every disease outbreak, researchers try to figure out how far — and how fast — a virus is likely to spread through a population. To do that, they use a number called an “R naught,” or R0. Most simply, the figure refers to how many other people one sick person is likely to infect on average in a group that’s susceptible to the disease. Here’s what we know so far about the Ro of Zika and Ebola.
Learn more about the World Health Organization’s work on the Ebola and Zika virus Act Now