How Horses become Zebras

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“Are you ready for sign out?”

“Yeah, gimme a second. I’ve gotta print a list.”

It was about 6:30 in the morning, and my fellow neurology residents were arriving at the hospital for another day in the grind. I had been there all night on call, and all of the previous day. The last time I had slept was about 25 hours before, and I only had about 3 hours to go before I could hit the sack. After I signed out the rest of my day would be easy: try to stay awake through morning lecture, and then try to stay awake while driving home.

“Ok, I’m ready.” The other resident had a freshly printed hospital census for the neurology ward service.

“Alright,” I said, pulling the list out of my white coat pocket. “The floor was pretty quiet overnight. The guy in room 28 wanted pain meds. 32B had another seizure, so I gave her lorazepam. There were three new admits overnight. I still need to write the H&P for one of them, but they’ve all been staffed and the orders are in.”

I spent a few minutes telling about the new admissions. An older man had a stroke. Another one had a myasthenia gravis excerbation. The third one was a mystery case. “Sunil admitted her from his clinic,” I said.

“Yeah, he called me about her yesterday,” the other resident said. “He thinks she has Behçet’s.”

“He’s a zebra hunter,” I said. “I think it’s probably just MS, but we’ll see. I ordered new scans and started her on pulse steroids.”


In the jargon of American medicine, rare and interesting diseases are known as zebras. The origin of this term is a little murky, but it has been attributed to Dr. Theodore E. Woodward, who taught medicine at the University of Maryland at Baltimore for nearly 50 years. He used to tell his students, “When you hear hoofbeats behind you, don’t expect to see a zebra.”

The young female patient I admitted to the hospital on that call night was far more likely to have multiple sclerosis (incidence ~1/1,000) than Behçet disease (incidence ~1/500,000, only 10% of whom have neurologic manifestations). Those hoofbeats were probably from a horse, and it’s usually a waste of time to go looking for less likely things.

But the human brain loves novelty, so the hunting of medical zebras will always be good sport among students and residents.


If I somehow traveled back in time to work as a doctor in some bygone day, I suspect that most of my knowledge and experience in modern medicine wouldn’t be very useful there. Many of the diseases that were bread-and-butter medicine in the past have now become rare in developed countries. Smallpox, that feared killer, has been eradicated. I have never personally seen a case of leprosy, malaria, measles, or mumps. My parents both had multiple friends and classmates who were affected by poliomyelitis, but I don’t know a single person from my own generation or younger who has had polio. Chickenpox, which I had as a child, now has an effective vaccine, so none of my children have had to experience it. Yesterday’s horses are today’s zebras.

And come to think of it, actual horses have become zebras for people who live in cities. I can only remember seeing one horse within the city limits during all of my eleven years in Columbus, Ohio.

But as recently as two generations before me, horses were everywhere. One day I was looking at some old black and white family photos, and it seemed like every other one showed an ancestor of mine on horseback. “That’s my grandpa,” I said to my little daughter, who was sitting next to me. Grandpa was a little boy in the picture, about her age, and he was riding bareback on a huge horse.

She looked at the picture wistfully, enviously, and said, “Old people are so lucky!”


What other horses could we relegate to zebras? Could we reach a day when the plagues of racism and other forms of prejudice are things of the past? Can we reasonably look forward to a time when no women or children are abused, and when poverty and hunger are conquered once and for all?

“Wherefore, whoso believeth in God might with surety hope for a better world, yea, even a place at the right hand of God, which hope cometh of faith, maketh an anchor to the souls of men, which would make them sure and steadfast, always abounding in good works, being led to glorify God” (Ether 12:4).

Yes, we can believe in these things, if we are determined to live out our faith.


These days an overnight call assignment for me is as rare as a zebra in Southern Utah. In my clinic I see a lot of common things, but now and again an unusual disease turns up just to keep things interesting. You don’t have to go hunting for them. I still haven’t diagnosed anyone with Behçet disease, though.

It would be nice if we could turn COVID-19 into a rare condition. We have the tools to do that now, if we will use them. I’d also like to see Alzheimer disease, Parkinson disease, stroke, and even migraine become medical zebras, but I don’t expect all of that to happen any time soon.

Our small rural town has a lot of horses; I see several every week on my morning runs. We also have racism, according to those I know who have experienced it here. Of course there are the poor and hungry in every community. And, sadly, the abuse of women and children seems to happen at some frequency wherever there are women and children to abuse.

But I have hope, through my faith, that better things are coming.

“And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away” (Revelation 21:4).

By the grace of God this fallen world will become the paradise it was created to be. And I want to be a part of making that happen.

Alan B. Sanderson is a member of The Church of Jesus Christ of Latter-day Saints and is a practicing neurologist. Zebras photos taken by Ivan L. and Glenna C. Sanderson while they were serving as missionaries in South Africa, 1994-1996.

One reply to “How Horses become Zebras

  1. This is lovely, especially after listening to a huge number of news reports of people experiencing terrible situations, both man made and natually caused.
    It seems that the natural world mimics or reacts to the evil things people are doing to each other.
    I too hope for a better world where people are good and we help each other get through anything that isn’t. I hope to see the day when Christ comes, and wrong is stopped, and right is established. Thank you for bearing your testimony in a public place.


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