When the director of the Centers for Disease Control and Prevention (CDC) compared Ebola to AIDS last week, he introduced a new note of urgency to the outbreak. As was the case in the early days of HIV, there are currently no approved drugs to treat Ebola, and the virus carries the potential to cause untold devastation—not to mention a lot of panic.

But as an epidemic, Ebola has far more in common with other diseases. Here’s a comparison of Ebola’s impact over the past 19 weeks to other recent outbreaks that, like Ebola, have no known cure or vaccine. Middle East Respiratory Syndrome (MERS) MERS is a viral respiratory illness first reported in Saudi Arabia in September 2012.

The World Health Organization has since reported 853 MERS infections, of which at least 301 were ...