The Unlikely Clue That Led Doctors in West Africa to Ebola: Hiccups

UNDATED:  In this handout from the Center for Disease Control (CDC), a colorized transmission electron micrograph (TEM) of a Ebola virus virion is seen. As the Ebola virus continues to spread across parts of Africa, a second doctor infected with the disease has arrived in the U.S. for treatment.  (Photo by Center for Disease Control (CDC) via Getty Images)
Photo: Center for Disease Control (CDC) via Getty Images

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 M.S.F. for the nonprofit’s French name, Medicins sans Frontieres), 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.

As Stern writes:

On March 14, M.S.F.’s Genevaoffice received a report from a medical investigation in Guinea. M.S.F. Geneva immediately forwarded the report to Dr. Michel Van Herp, an epidemiologist in its Brussels office, and one of the world’s leading experts on Ebola. When Van Herp opened the document, what immediately jumped out at him was that half the victims had developed hiccups.

But why would Ebola trigger a case of the hiccups? Stern writes that researchers aren’t sure. There are some theories, though, according to Paula Cannon, a virologist at the University of Southern California.

First, hiccups 101: They happen when the diaphragm — a flat muscle at the bottom of the rib cage that aids in breathing — involuntarily contracts. This forces you to quickly draw in a breath, which is then caught in your vocal cords as they close; this produces the “hic” sound. Hiccups are generally triggered by some sort of irritation to the diaphragm, and Cannon thinks that could explain the association with Ebola.

She wrote in an email to Science of Us:

I’d guess that the infection or some consequence of it is irritating components of the nervous system that eventually trigger the reflex contractions in the diaphragm that cause hiccups - in the same way that regular hiccups are thought to be triggered by pretty disparate things like laughing, spicy food, and some other random diseases.

Hemorrhagic fevers result in a lot of general disregulation in many body processes, so maybe that’s the way to think about it. In other words, if you have a bad case of a hemorrhagic fever, you will be spiraling down in terms of symptoms, and it becomes a perfect storm. Your body’s ability to maintain normal “housekeeping functions” starts to be impacted.

Brian Lewis, an epidemiologist at Virginia Tech’s Network Dynamics & Simulation Science Laboratory, added this in an email:

My suspicion is that this would be related to the way the virus affects that body.  It basically starts flushing all the fluid out of many of your cells, which leads to the diarrhea and vomiting many experience, but I could see where having a lot of internal “fluid buildup” might induce hiccups.  

Interesting theories if you’re a virology nerd or public-health researcher in Africa. Not so much if you’re a hypochondriac with the hiccups.

How Hiccups Helped Doctors Identify Ebola