In 2016, panic spread through the Americas as a once obscure virus—Zika—reached epidemic proportions. To the surprise of the medical community and the public alike, the little known virus was discovered to cause severe birth defects in children born to infected mothers. But where did this virus come from? And how did it suddenly become a problem of such devastating proportions? A year after the devastating disease exploded in the Americas, NOVA takes a closer look at how this virus grew to become such a monster. We join a small band of researchers who knew about Zika before it made headlines as they trace the disease back to its origins... back to the tropical forests of Uganda, where it was discovered during a golden age of virus discovery.
NARRATOR : This is a story that began long ago, in a small forest in Uganda on the banks of a great lake.
...a story about something so tiny that it lived in the belly of a mosquito.
Yet loomed large in the imagination of a little boy named Andrew Haddow, who learned of it from his grandfather’s tales.
Andrew grew up to be a scientist who studies insects,
And this tiny something,
grew into a terrible force,
An epidemic we call Zika.
And when it left the forest to spread harm around the Earth,
Andrew found himself in the middle of a science mystery...
...that began on a day long before he was born.
ANDREW HADDOW : April of 1947, the original isolation of Zika virus made by Dick, Kitchen, and my grandfather, Alexander John Haddow; he went by ‘Alec.’
NARRATOR : Andrew’s grandfather, Alec Haddow, discovered Zika during a decades-long hunt for yellow fever in the rainforests of East Africa.
ANDREW HADDOW : Here's a picture of my grandfather. I mean, he looks like a pirate.
He kind of just did his own thing.
NARRATOR : The tales of his adventures inspired Andrew as a young boy...
ANDREW HADDOW : …stories of my grandfather going out into the bush…about elephants and wildlife and everything...so exciting to a little kid.
NARRATOR :Sometimes they were medical mysteries...
ANDREW HADDOW : …numerous bedtime stories involving viruses
NARRATOR : His favorite: the stories about Zika
ANDREW HADDOW : I think why Zika appealed to me was this idea of the tower.This mythical, giant, steel tower.
NARRATOR :Alec Haddow designed this tower to conduct experiments in and above the tropical forest canopy of Uganda.
ANDREW HADDOW :And, you know, to a four or five-year-old, that's...pretty cool.
…catching mosquitoes, and studying monkeys…
The tower had various platforms
NARRATOR :They would put monkeys up in the canopy to get bitten by mosquitos, in experiments designed to examine the spread of Yellow Fever in the jungle.If a monkey became sick, they tested its blood.
ANDREW HADDOW :They were actually looking for Yellow Fever virus.
NARRATOR :One day, when a bitten monkey became ill...
ANDREW HADDOW : Sentinel rhesus monkey number MR 766...
NARRATOR : …Their tests for yellow fever came up negative.
ANDREW HADDOW : They didn’t know what they had; they just knew they had something. And, it turned out it was a new virus.
NARRATOR : As is often the custom in virology, discoveries are named after where they are found.
And so Haddow and his team named the virus after the forest in Uganda where their tower stood: Zika.
ANDREW HADDOW : The Lugandan spelling has two “I’s.”
NARRATOR : Over the course of their expedition, the team identified and studied about a dozen viruses in all.
Yet the discovery of Zika virus drew little notice.
ANDREW HADDOW : I don't think they thought much of it; it wasn't associated with human illness—
NARRATOR : And so the virus slipped into obscurity in the half century that followed… But Andrew never forgot about Zika.
ANDREW HADDOW : Since I, you know, was 3 or 4 years old I wanted to be a researcher. I didn’t exactly know at the time what a researcher was, but I knew I wanted to do that.
NARRATOR : And he did.
In 2009, Andrew came to the University of Texas Medical branch to work with Drs. Scott Weaver and Robert Tesh, in one of the few places studying the Zika virus.
SCOTT WEAVER : You could count them on one hand the number of laboratories doing anything with Zika.
NARRATOR : They had the world’s largest collection...
ROBERT TESH : ...about thirty strains of the virus.
NARRATOR : …including one that was very important to Andrew...
ANDREW HADDOW : The prototype strain; the original isolation of Zika.
ROBERT TESH : ...your grandfather’s virus.
ANDREW HADDOW : ...from his hand, in a sense, to my hand.
NARRATOR : Starting at Zika’s origins, with the very strain that his grandfather discovered…
ANDREW HADDOW : Strain IBH...30...656...
SCOTT WEAVER : Nigeria 1968
NARRATOR : …Andrew set out to learn everything he could about this virus, that was about to spread throughout the world.
ANDREW HADDOW : 41519...
NARRATOR : ...For over half a century, Zika was mostly confined to the tropics through Africa, India, and South East Asia.
It was a virus so rare, that only 14 confirmed cases of Zika illness had ever been documented in humans.
But a series of unexpected events would challenge everything they thought they knew about the virus.
Starting here on Yap Island…
SCOTT WEAVER : ...a very small island only about 7,000 people live there, but more than half of them became infected with Zika virus.
ANDREW HADDOW : It was just, "woah, you know. Zika is causing an outbreak, like a big outbreak."
SCOTT WEAVER : But the outbreak was still characterized by a very mild disease, uh, fever, rash, nothing particularly serious...
NARRATOR : Or so they thought.
Zika had gone back into hiding. For now.
But two years later, Andrew would again cross paths with the virus.
And it would reveal a bizarre secret.
ANDREW HADDOW : …something was very strange with this virus. Something that I don’t think anybody could anticipate.
NARRATOR : A medical mystery that Andrew came upon and solved, in a chance meeting.
ANDREW HADDOW : The diagnosis was made in a bar, over a beer in a bar in Senegal.
It all started in the summer of 2009 when I met Kevin Kobylinski. We started having a conversation.
BRIAN FOY : Kevin's my graduate student. He's in Australia right now.
KEVIN KOBYLINKSKI : Hey, Brian. Hey, Andrew.
BRIAN FOY : We were talking about you and Andrew in the bar in Senegal.
KEVIN KOBYLINKSKI : Excellent.
ANDREW HADDOW : After we talked about our various projects...
KEVIN KOBYLINKSKI : Right. Right...
ANDREW HADDOW : Kevin started to describe an illness that he and Brian came down with the year earlier.
NARRATOR : Brian and Kevin were in Senegal working on a project.
BRIAN FOY : …collecting mosquitoes out of people's huts…
NARRATOR : And when they flew back to Fort Collins, Colorado, where they lived, they started to feel sick.
KEVIN KOBYLINKSKI : Brian and I started having similar symptoms.
NARRATOR : Symptoms like a rash, headache, and joint pain.
KEVIN KOBYLINKSKI : And then, we had our blood drawn...
BRIAN FOY : And called up the CDC...
NARRATOR : The Centers for Disease Control conducted a series of tests...
ANDREW HADDOW : Dengue…
BRIAN FOY : Yellow Fever…
ANDREW HADDOW : Chikungunya…
NARRATOR : …for the usual suspects. And the results?
BRIAN FOY : Negative. Negative, negative, negative.
ANDREW HADDOW : The most common ones were ruled out.
They still didn't know what they had been infected with.
NARRATOR : Kevin, Brian, and the CDC were confounded by this mystery illness.
BRIAN FOY : So, we stuck our serum samples in the freezer and left it for another day.
NARRATOR : And that day came when Kevin and Andrew had their chance meeting in Senegal.
KEVIN KOBYLINKSKI : A year later, we're at this bar having this discussion and, um, the picture became a lot more clear.
First words out of your mouth were that the symptoms sounded just like—
ANDREW HADDOW : Zika!
KEVIN KOBYLINKSKI : Zika!
NARRATOR : At least that was Andrew’s theory.
ANDREW HADDOW : What else is there?
NARRATOR : But he needed proof.
ANDREW HADDOW : I'm just like, "Oh my God. We've got to get these samples..." Like, I so wanted their blood.
KEVIN KOBYLINKSKI : He said that the laboratory that he was working at definitely could perform the antibody test.
ANDREW HADDOW : I’ll have Dr. Tesh run it.
Then Kevin takes a sip of beer and says, "Well, there’s one more thing:
Brian's wife got sick too."
KEVIN KOBYLINKSKI : His wife started having the rash and feeling bad and swelling in her joints.
ANDREW HADDOW : Same signs and symptoms, very interesting.
KEVIN KOBYLINKSKI : And she was not in Southeastern Senegal.
ROBERT TESH : No, she was not.
NARRATOR : What peaked their interest was this...
The mosquitos that transmit Zika live in warm places, like the tropics.
If this was in fact a Zika infection— how could Brian’s wife have possibly contracted the disease in Colorado?
BRIAN FOY : It's a tropical virus that can’t be transmitted by mosquitoes in Northern Colorado.
NARRATOR : They ruled out other means of transmission as well.
The smoking gun seemed to be a rather unusual set of symptoms Brian experienced:
BRIAN FOY : …prostatitis and hematospermia...
ANDREW HADDOW : ...which is?
BRIAN FOY : ...blood in the semen and inflamed prostate.
KEVIN KOBYLINKSKI : That's when we became excited about the possibility of it being, uh, sexually-transmitted.
NARRATOR : Sexually transmitted?
BRIAN FOY : A very novel and risky hypothesis.
ANDREW HADDOW : Totally out there.
NARRATOR : Indeed.
It was believed that the only way people could get an infection like this, was through mosquitos.
Sexual transmission, if it were the case, would be a revolutionary finding.
ANDREW HADDOW : Like saying a car can drive on a square wheels.
NARRATOR : But of course they were getting ahead of themselves...
KEVIN KOBYLINKSKI : We had no idea what we actually even had...so...
NARRATOR : They hadn’t yet identified what the virus was.
ROBERT TESH : Well, I have here the serologic results.
NARRATOR : Then, Dr. Tesh revealed his findings.
ROBERT TESH : Kevin, Brian, and Brian's wife had Zika.
ANDREW HADDOW : I was like, "Holy cow, it's Zika."
BRIAN FOY : Grandfather would be so proud.
NARRATOR :Andrew’s diagnosis, Zika, was correct.
BRIAN FOY : Mystery solved.
NARRATOR : But not much was made of their discovery of the sexual transmission.
BRIAN FOY : No.
NARRATOR : Because at this point, Zika was thought to be an obscure and mild virus.
ANDREW HADDOW : It at least was something that we needed to be aware of, and maybe kind of keep on our radar, that this virus could do weird things.
NARRATOR : Yet Andrew could not be prepared for what was about to unfold.
Zika resurfaced in a tremendous outbreak.
SCOTT WEAVER : Here in French Polynesia about 200,000 people living in that area, and more than half of them became infected with Zika virus.
ANDREW HADDOW : An epidemic in the Tropics—the final big “Red flag."
SCOTT WEAVER : All of those people infected many of them traveling by air...
The virus spread all over the South Pacific
NARRATOR : In the fall of 2015, Zika struck hard in Brazil.
As it tore through the country, Zika revealed its darkest secret, yet.
And it was devastating…
The Zika virus appears to be a lot scarier than first thought.
ANDREW HADDOW : All of a sudden we start getting reports of neurological problems…
SCOTT WEAVER : ...congenital infections...
...a devastating birth defect...
ANDREW HADDOW : ...babies being born with microcephaly.
NARRATOR : Microcephaly—a devastating birth defect where a baby’s brain is smaller than normal.
...the result of improper neurological development.
That Zika could be responsible seemed almost unbelievable to Andrew.
ANDREW HADDOW : Microcephaly, it can’t be causing that. No one’s ever heard of anything like this for one of these viruses.
NARRATOR : Most virologists remained skeptical—until a group of Brazilian pediatricians observed the connection between Zika and these neurological birth defects.
ANDREW HADDOW : They led that charge that maybe Zika’s causing microcephaly. And it turned out they were correct.
NARRATOR : Now everyone looked at the virus in a whole new light.
SCOTT WEAVER : From thinking about this virus as a very mild virus—to now thinking it's one of the most dangerous.
ANDREW HADDOW : It was just so sad and overwhelming to see what this virus is doing to the most innocent population: children.
You know, it was this cool, mythical virus. It doesn't hurt anyone. Nothing bad happens.
So a door just slammed. The forest, and the tower...it was just kind of like, gone.
“…A public health emergency of international concern...”
“…Take a look at this map. The outbreak, moving north…”
SCOTT WEAVER : Air travelers returned to the United States infected by the virus…
Miami... Texas, Illinois...
...and Hawaii, all showing cases.
SCOTT WEAVER : ...and now we’ve seen local mosquito borne transmission.
“… Zika virus by mosquitos..”
“…Right here in the U.S.”
NARRATOR : Dr. Weaver expanded his team’s efforts to investigate how the virus could have turned into such a monster…
SCOTT WEAVER : …to understand the disease process of microcephaly…
NARRATOR : … and to search for a cure.
SCOTT WEAVER : …developing anti-viral drugs as well as vaccines…
“… Zika virus spread through sex…”
NARRATOR : Brian has returned to his research on sexual transmission of the virus.
BRIAN FOY : The question is: How important? How prevalent it is relative to mosquito borne transmission?
NARRATOR : And Andrew continues to investigate the mysterious virus his grandfather discovered in Uganda so long ago.
ANDREW HADDOW : People are counting on all of us to get an answer quickly.
NARRATOR : No one knows if Zika will again cause such a widespread crisis…
Yet another in a long line of viral outbreaks that seemingly emerged from nowhere.
SCOTT WEAVER : There are probably a lot of viruses out there that aren’t being discovered because field studies around the world have really fallen by the wayside in the last few decades.
NARRATOR : It may be that the best path forward in preparing for future epidemics is a return to the practices of virus hunters like Alec Haddow...
ANDREW HADDOW : We realize today they were ahead of the game,
NARRATOR : Scientists who searched the tropical forests of the world in a race to find viruses, before they found us...
…and fired young imaginations, with a well spun tale or two.
Andrew Haddow, United States Army Medical Research Institute for Infectious Diseases
Robert Tesh, University of Texas Medical Branch
Scott Weaver, University of Texas Medical Branch
Brian Foy, Colorado State University
Kevin Kobylinski, Armed Forces Research Institute of Medical Sciences
- Produced by
- Kevin Young and Caitlin Saks
- Directed and Edited by
- Vincent Liota
- Written by
- Caitlin Saks and Vincent Liota
- Director of Photography
- Vincent Liota
- Design and Animation
- Vincent Liota
Dr. Milly Kayongo
- Sound Operator
- J.R. Rodriguez
- Tedi Rabold
- Priya Amin
- Director of Digital Media for NOVA
- Lauren Aguirre
- Associated Production Music
- Additional Footage
Miles O'Brien Productions
University of Texas Medical Branch
- Special Thanks
University of Texas Medical Branch
- Andrew Haddow
- Robert Tesh
- The Alec Haddow Archive at the University of Glasgow Rockefeller Foundation, “Lamia valley malaria field studies, Ypati laboratory,” 100 Years: The Rockefeller Foundation, accessed November 18, 2016 © Courtesy of Rockefeller Archive Center
- Rockefeller Foundation, “West African Yellow Fever Commission,” 100 Years: The Rockefeller Foundation, accessed November 18, 2016, © Courtesy of Rockefeller Archive Center