So many devastating, horrifying stories have come out of the ongoing Ebola crisis ravaging West Africa. This one, however, is one of the more surprising nuggets to emerge. In a new piece for Vanity Fair, journalist Jeffrey E. Stern describes the unlikely way researchers identified the disease as it first started to spread across Guinea - all thanks to a single, odd symptom: hiccups.

People tend to associate the Ebola virus with all parts of Africa, but the truth is, Ebola had never before been seen in Guinea, Stern told NPR, which meant researchers from Doctors Without Borders (called MSF for the nonprofit’s French name, Médecins sans Frontières), not expecting to see the virus on that part of the continent, were stumped for months as the number of victims skyrocketed. They were further stymied by the fact that, in its earliest stages, Ebola symptoms look a lot like those of malaria or cholera.

There’s one exception, though, and it helped medical experts crack the case: Ebola can cause hiccups, while those other diseases do not.