DAVID GREENE, HOST:
A small group of scientists saw some ominous signs a few years ago, signs of a possible outbreak of Ebola in West Africa. They had trouble getting anyone to listen to them. Now an outbreak has killed thousands there, and people are starting to listen to those scientists. They're beginning to pick up clues of where Ebola could strike next. NPR's Michaeleen Doucleff spoke with them.
MICHAELEEN DOUCLEFF, BYLINE: A few years ago, disease ecologist David Hayman made the discovery of a lifetime. He was a graduate student with the University of Cambridge, studying Ebola. And he spent a lot of that time hiking around the rain forest in West Africa...
(SOUNDBITE OF INSECTS CHIRPING)
DOUCLEFF: Catching hundreds of fruit bats.
DAVID HAYMAN: We would set large nets up into the tree canopies. And then, early morning, when the bats are looking for fruit to feed on, we would catch them, pull down the nets and then take the bats out.
DOUCLEFF: Hayman held each bat in his hands, spread its giant wings and pricked it with a tiny needle. All he wanted was one drop of blood. You see, bats have a huge number of viruses in their blood. When Hayman took the samples back to the lab, he found a foreboding sign.
HAYMAN: A high level of antibodies against Ebola virus.
DOUCLEFF: The antibodies meant the bats had been infected with Ebola or something related to it. Hayman knew right away that West Africa was at risk for an outbreak. And he thought health officials would be worried too.
HAYMAN: We were all prepared for a sort of response for questions. And I have to say, not many came.
DOUCLEFF: That was two years ago. Now health officials are definitely listening to Hayman. Scientists think that fruit bats triggered the entire Ebola epidemic in West Africa, just as Hayman predicted. So a big question now is, where else in the world is Ebola hiding? Kevin Olival is an ecologist at EcoHealth Alliance in New York City. He hunts down another virus in bats called Nipah. It causes your brain to swell and then puts you in a coma. Olival says Nipah is so gruesome, it inspired a Hollywood movie.
(SOUNDBITE OF FILM, "CONTAGION")
KATE WINSLET: (As Dr. Erin Mears) Hello?
DAN AHO: (As Aaron Barnes) Hello?
WINSLET: (As Dr. Erin Mears) Mr. Barnes?
AHO: (As Aaron Barnes) Yes.
WINSLET: (As Dr. Erin Mears) This - this is Dr. Mears from the Centers for Disease Control.
DOUCLEFF: That's Kate Winslet in the movie "Contagion." Her job was to break the bad news to people that they had the Nipah-like virus.
(SOUNDBITE OF FILM, "CONTAGION")
WINSLET: (As Dr. Erin Mears) Listen. It's quite possible you've come in contact with an infectious disease and that you're highly contagious.
DOUCLEFF: And Nipah is also quite deadly. It causes outbreaks every few years in Bangladesh, so Olival went there in 2010 and captured a bunch of bats. Many had signs of Nipah in their blood. Others had something surprising.
KEVIN OLIVAL: There's antibodies to something related to Ebola Zaire.
DOUCLEFF: Ebola Zaire is the type of virus spreading around West Africa right now. It's also the most deadly form of Ebola. Until this discovery, scientists thought Ebola Zaire was found only in Africa. Now they've found signs of it in Bangladesh and China.
OLIVAL: If you think about geographic space, it was a big shock to find, you know, evidence for this virus in a very faraway place in South Asia.
DOUCLEFF: Does that make you think that Ebola could emerge in Bangladesh?
OLIVAL: (Laughter). Well, that's a tricky one. I think if you have the right, you know, combination of potential events and sort of the perfect storm brews, then yeah, it's possible.
DOUCLEFF: Olival is working with USAID to build an Ebola early warning system around the world. Now, there's no sign bats have infected people in Asia yet. And David Hayman says it's actually quite rare for bats to pass Ebola on to people.
HAYMAN: There's an enormous amount of human-bat contact in - generally. And, you know, in a way, maybe we should question why there've been so few outbreaks.
DOUCLEFF: Still, these ecologists say it's not whether a virus in the Ebola family will cause an outbreak outside of Africa, but a matter of when and where. Michaeleen Doucleff, NPR News.
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