With each outbreak of the world’s most fearsome disease, an ad hoc team of doctors and researchers risk their own lives by heading straight for ground zero. Tom Clynes joins them at the epicenter as they battle to contain the virus–and trek into the forest in search of its secrets.

When the old Czech prop-plane lurches to a halt at the side of the military airstrip, the six doctors unfurl their stiff legs, disembark, and begin unloading. They shift 47 boxes—a metric ton of laboratory gear—onto a truck and drive toward town, trailing a spiral of orange dust as they pass army checkpoints and outsized churches, roadside vendors and crowds of people listening to radios, talking, and singing.

The most surprising thing is how ordinary it all looks, at first. Set in the middle of a fertile, if unrelieved, savanna, Gulu could be any other East African provincial center. Everywhere, people are on the move, some pedaling bikes, others riding on the fringed rear seats of bicycle taxis, most just walking. They walk upright, with stone-straight posture, some carrying babies on their backs, some balancing loads on their heads, some bare-footed, others in sandals. They walk—and the doctors drive—past the field where the Pope once spoke, from atop two shipping containers still piled one atop the other; past the turnoff that leads to the witch doctor’s house; past another road that leads to a small village near the forest—the forest where, perhaps, it all started.

It takes a few minutes, as if the doctors’ eyes were getting used to a new light, before hints begin to emerge that life here is far from normal. There are none of the usual swarms of children in school uniforms. White trucks drive through town, emblazoned with the red crosses and acronyms—UN, WHO, MSF—that portend crisis. The hospital building, where the doctors pull up, is wrapped in white plastic sheeting. At the door, a hand-lettered sign warns “No entrance without permission.” The sign is illustrated with a crude human figure, with an X drawn over it.

###

Dr. Anthony Sanchez got the news on a Sunday afternoon in mid-October when he stopped by his lab at the Centers for Disease Control and Prevention, in Atlanta. Sanchez was surprised to find his boss, Pierre Rollin, in the office. Rollin told him that Ebola, after a four-year respite, had resurfaced in northern Uganda.

“Feel free to say no, Tony,” Rollin said. “But I’m putting together a team to go over and set up a lab; we could use you.”

Sanchez had a four-month-old daughter at home, his first. But the agency was already spread thin, with a team in Saudi Arabia covering a Rift Valley fever epidemic. An on-site laboratory could give the Ebola containment operation a tremendous advantage.

Sanchez, a low-key Texan, had spent much of his career researching the virus, often in the CDC’s maximum-containment lab, protected by a space suit. But he had never seen it operate in a human epidemic. Once, a few years ago, he had wondered if he had missed his chance, if the disease would ever come again.

Sanchez walked to his office and picked up the phone. He dialed his home number and told his wife that there was something he needed to talk about when he got home, something important. The line was silent for several long seconds, and then:

“I’m not going to be happy about this, am I?”

###

Five weeks into the crisis, a crowd of foreigners occupies a government office room in a yellow concrete-block building on the north side of Gulu. Doctors and scientists hunch over notebook computers and talk into walkie-talkies. Through the babble of languages and accents, an American voice speaks into a satellite telephone: “We’ve got more positives in Pabo now—we’ve got to get on top of this.”

After she hangs up the phone, I walk over and introduce myself to Cathy Roth, a World Health Organization physician who is, at the moment, coordinating the operation. When I extend my hand, she throws both of her hands over her head in a “don’t shoot!” gesture.

“Uh, we’re not actually doing that anymore,” Roth says, smiling down at my retreating hand. Ebola is spread through contact with bodily fluids, including sweat. And although it’s unlikely that either of us would be carrying the virus, people are avoiding handshakes like . . . well, like the plague.

A dozen or so exhausted-looking professionals trudge into the room for Roth’s afternoon update meeting. “Everyone’s getting really tired now,” she says. “We were thinking we had it under control, and I was thinking about giving the mobile teams a Sunday off. After five weeks of 24-7, they’re making mistakes, and they need rest.” But now Roth is worried that the illness is flaring up again, threatening to break through the containment operation.

In the past, Ebola had struck only rural areas, and the disease’s rapid death sequence had actually worked in favor of containment, since infected people couldn’t travel far before they toppled over. But the Gulu area is densely populated, with transport links to East Africa’s major cities—and, from there, to anywhere in the world. No one knows what might happen if the virus were given the chance to take advantage of these more favorable conditions.

CDC epidemiologist Scott Harper begins the meeting with bad news from Pabo, a refugee camp north of Gulu…

The complete story appears in the anthology “The New Age of Adventure: Ten Years of Great Writing”