The Hot Zone

by Richard Preston

  “Yes. Nancy Jaax showed them to me.”

  “Then you know. You can see Ebola particles clearly in the air spaces of the lung.”

  “Did you ever try to see if you could put Ebola Reston into the air and spread it among monkeys that way?” I asked.

  “No,” he replied firmly. “I just didn’t think that was a good idea. If anybody had found out that the Army was doing experiments to see if the Ebola virus had adapted to spreading in the respiratory tract, we would have been accused of doing offensive biological warfare—trying to create a doomsday germ. So we elected not to follow it up.”

  “That means you don’t really know if Ebola spreads in the air.”

  “That’s right. We don’t know. You have to wonder if Ebola virus can do that or not. If it can, that’s about the worst thing you can imagine.”

  Ebola Zaire virus particles magnified 17,000 times. Note the loops at the ends of some particles, the so-called shepherd’s crooks or eyebolts, which are typical of Ebola Zaire and its sisters. Photograph by Thomas W. Geisbert, USAMRIID.

  Ebola Reston virus particles. “The point is, you can’t easily tell the difference between the two strains by looking.”—Peter Jahrling. Photograph by Thomas W. Geisbert,

  USAMRIID.

  • • •

  So the three sisters—Marburg, Ebola Sudan, and Ebola Zaire—have been joined by a fourth sister, Reston. A group of researchers at the Special Pathogens Branch of the C.D.C.—principally Anthony Sanchez and Heinz Feldmann—have picked apart the genes of all the filoviruses. They’ve discovered that Zaire and Reston are so much alike that it’s hard to say how they are different. When I met Anthony Sanchez and asked him about it, he said to me, “I call them kissing cousins. But I can’t put my finger on why Reston apparently doesn’t make us sick. Personally, I wouldn’t feel comfortable handling it without a suit and maximum containment procedures.”

  Each filovirus strain contains seven proteins, four of which are completely unknown. Something slightly different about one of the Reston proteins is probably the reason the virus didn’t go off in Washington like a bonfire. The Army and the C.D.C. have never downgraded the safety status of Reston virus. It remains classified as a Level 4 hot agent, and if you want to shake hands with it, you had better be wearing a space suit. Safety experts feel that there is not enough evidence, yet, to show that the Reston strain is not an extremely dangerous virus. It may be, in fact, the most dangerous of all the filovirus sisters, because of its seeming ability to travel rather easily through the air, perhaps more easily than the others. A tiny change in its genetic code, and it might turn into a cough and take out the human race.

  Why is the Reston virus so much like Ebola Zaire, when Reston supposedly comes from Asia? If the strains come from different continents, they should be quite different from each other. One possibility is that the Reston strain originated in Africa and flew to the Philippines on an airplane not long ago. In other words, Ebola has already entered the net and has been traveling lately. The experts do not doubt that a virus can hop around the world in a matter of days. Perhaps Ebola came out of Africa and landed in Asia a few years back. Perhaps—this is only a guess—Ebola traveled to Asia inside wild African animals. There have been rumors that wealthy people in the Philippines who own private estates in the rain forest have been importing African animals illegally, releasing them into the Philippine jungle, and hunting them. If Ebola lives in African game animals—in leopards or lions or in Cape buffalo—it might have traveled to the Philippines that way. This is only a guess. Like all the other thread viruses, Ebola Reston hides in a secret place. It seems quite likely, however, that the entire Reston outbreak started with a single monkey in the Philippines. One sick monkey. That monkey was the unknown index case. One monkey started the whole thing. That monkey perhaps picked up four or five particles of Ebola that came from … anyone’s guess.

  PART FOUR

  KITUM CAVE

  Highway

  1993 AUGUST

  The road to Mount Elgon heads northwest from Nairobi into the Kenya highlands, climbing through green hills that bump against African skies. It goes through small farms and patches of cedar forest, and then it breaks over a crest of land and seems to leap out into space, into a bowl of yellow haze, which is the Rift Valley. The road descends into the Rift, cutting across wrinkled knees of bluffs, until it hits bottom and unravels on a savanna dotted with acacia trees. It skirts the lakes at the bottom of the Rift and passes through groves of fever trees, yellow-green and glowing in the sun. It is detained in cities that dwell by the lakes, and then it turns westward, toward a line of blue hills, which is the western side of the Rift, and it climbs into the hills, a straight, narrow, paved two-lane highway, crowded with smoky overlander trucks gasping up the grade, bound for Uganda and Zaire.

  The road to Mount Elgon is a segment of the AIDS highway, the Kinshasa Highway, the road that cuts Africa in half, along which the AIDS virus traveled during its breakout from somewhere in the African rain forest to every place on earth. The road was once a dirt track that wandered through the heart of Africa, almost impossible to traverse along its complete length. Long sections of it were paved in the nineteen-seventies, and the trucks began rolling through, and soon afterward the AIDS virus appeared in towns along the highway. Exactly where the virus came from is one of the great mysteries.

  The road to Mount Elgon was familiar to me; I had traveled over it as a boy. My parents and my brothers and I had lived for a short while with a Luo family on their farm in the hills overlooking Lake Victoria—a traditional farm, with mud huts and a boma for keeping cattle. I had not been back to Africa since I was twelve years old, but when you have encountered Africa in childhood, it becomes a section of your mind. I had felt warm river sand on my bare feet and had smelled crocodiles. I knew the crispy sensation of tsetse flies crawling in my hair. I could still hear the sound of voices speaking English in the soft accents of the Luo language, urging me to feel free, feel free, eat more fat from the ram’s tail. I knew what it felt like to wake up in gray light before dawn not knowing where I was, seeing a mud wall with a hole in it, and gradually realizing that the hole was a window in a hut and that I was being watched through the window by a crowd of children. When I saw Africa again, Africa came back whole, alive, shining with remembered enigma. What came back first was the smell of Africa, the smoky smell of cooking fires, which produce a haze of burning acacia and blue-gum wood that covers the towns and clings to the bodies of people. What came back to me next, with a slap of recognition, was the sight of crowds of people walking along the roads as if they had been walking since the beginning of time, heading nowhere and everywhere by foot. In the highlands of Kenya, their bare and sandaled feet pound the shoulders of the highway into braids of red clay. The women sing Christian hymns as they walk, and some carry guitars, or they carry sacks of charcoal or salt balanced on their heads.

  The Land Rover smashed through a pall of diesel smoke and bounced as it hit a pothole. Robin MacDonald, my guide, gripped the steering wheel. “Oh, this road is good, man,” he said approvingly. “Last time I was here, it was so bad you would be crying by now. I haven’t been up to Mount Elgon in years—not since I was a kid, really. My old man had a friend who had a shamba up there”—shamba, a farm—“and we used to visit him all the time. Oh, it was lovely, man. That farm is gone now. Eh, it’s kwisha.” Kwisha: finished. He dodged around a herd of goats, using his horn liberally. “Get out of the way, man!” he shouted at a goat. “Look, he’s not even moving.” The Land Rover roared and accelerated.

  The road passed through small cornfields. In the middle of each plot stood a hut made of mud or cement. People stooped among the cornstalks, hand-tilling their fields with mattocks. Every inch of land lay under cultivation, right up to the doors of the houses. We passed a man standing by the road, holding a suitcase tied up with string. He waved to us. We passed another man wearing an English raincoat and a fedora hat and carrying a s
tick, walking slowly: a gray figure in bright sun. Some people waved as we passed, and others turned around in their tracks and stared at us. We stopped to wait for a herd of cattle crossing the road, driven by Kikuyu boys holding switches.

  “Ay,” Robin said dreamily. “When I was a kid, this country was different, eh? To get anywhere in this country was a three-day trip. We shot a bloody Thomson’s gazelle and lived off the thing the whole time. In the old days, twenty years ago, this land was all forest and grassland. Now it’s corn. Everywhere corn. And the forests are gone, man.”

  Robin MacDonald is a professional hunter and safari guide. He is one of about two dozen professional hunters who are left in East Africa. They take clients into the bush to hunt big game. He has a broad, ruddy face, thin lips, piercing eyes behind eyeglasses, and broad cheekbones. He has black, curly hair that hangs in pieces around his forehead, looking like he’d chopped it off with a knife. For walking in the bush, he wears a baseball cap, a black T-shirt, shorts, a curved African knife at his belt, and scorched, melted green sneakers—dried too many times over campfires. He is the son of a famous professional hunter named Iain MacDonald, who was killed at the controls, of a light plane that crashed on the African plains in 1967, when Robin was thirteen. By that time, Robin had learned what he needed to know. He had hunted leopard and lion with his father, and he had already shot his first charging Cape buffalo while his father stood beside him to make the back-up shot in case he missed. Robin tracked elephant with his father for days through the dry thornbush of the Yatta Plateau, carrying nothing but a canteen of water and one apple—“That client, he was a guy from Texas, that guy,” Robin explained. “He said he could walk it no problem, said he was an experienced hunter. He sat down one day and said, To hell with this, I can’t go on. Make me a camp.’ So we made him a camp, and we went on, my old man and I, and we stalked the elephant for two days. My old man only took water when he was tracking an elephant. Said to me, ‘Stuff an apple in that pack, and we’ll be off.’ And then we walked across the Yatta Plateau for two days. When we found the elephant, we led the client to it, and he shot it.”

  “How old were you then?”

  “Seven, man.”

  He does not hunt elephants anymore—he approves of the current worldwide ban on ivory—but he does hunt Cape buffalo, which is not an endangered species.

  There had been reports of tribal violence around Mount Elgon. The Elgon Masai had been raiding the Bukusu, an ethnic group whose people live on the southern side of the mountain, and had been burning their huts, shooting them with automatic weapons, and driving them off their land. I was concerned about the situation and had telephoned Robin from the United States to ask him his opinion.

  “Where do you want to go? Mount Elgon?” he had said. His voice sounded hissy and remote on the line.

  “I’m bringing a couple of space suits with me,” I said.

  “Whatever, my man.”

  “Is it safe to travel around Mount Elgon?”

  “No hassle. Not unless there’s a bloody uproar.”

  He lighted a cheap African cigarette and glanced at me. “So what are your plans for the cave? Are you going to collect any specimens? Any boxes of bat shit or the like?”

  “No, I just want to look around.”

  “I used to go up to that cave when I was a kid,” he said. “So there’s a disease up there, eh? Makes AIDS look like a sniffle, eh? You turn into soup, eh? You explode, eh? Pfft!—coming out of every hole, is that the story? And how long does it take?”

  “About seven days.”

  “Oof! Man. How do you get it?”

  “By touching infected blood. It may also be airborne. It is also sexually transmitted.”

  “Like AIDS, you mean?”

  “Yes. The testicles swell up and turn black-and-blue.”

  “What! Your guliwackers blow up? Lovely! So you get balls like a blue monkey! Christ! That virus is a bloody shit, that one.”

  “You have given a good description of the agent,” I said.

  Robin breathed his cigarette. He removed the baseball cap from his head and smoothed his hair and replaced the cap. “Right, then. You’ll go inside the cave and have a look at bat shit. And then—and then—after you explode in one of my tents, what shall I do with you?”

  “Don’t touch me. You could get very sick if you touch me. Just roll up the tent with me inside it, and take the thing to a hospital.”

  He crinkled with laughter. “Right. We’ll call in the Flying Doctors. They’ll pick up anything. And which hospital shall we have you delivered to, eh?”

  “Nairobi Hospital. Leave me by the Casualty entrance.”

  “Right, my man. That’s what we’ll do.”

  The Cherangani Hills appeared in the distance, a line of mountains on the edge of the Rift, humpy and green, crushed under an indwelling sweep of rain clouds. The clouds darkened and gathered together as we approached Mount Elgon, and splats of rain began to hit the windshield. The air turned cold and raw. Robin turned on his headlights.

  “Did you find some bleach?” I asked him.

  “I’ve got a gallon in back.”

  “Plain laundry bleach?”

  “Right. We call it Jik here in Kenya. Bloody Jik.”

  “Is it like Clorox?”

  “Right. Jik. Drink it, and it will bloody kill you.”

  “I hope it kills Marburg.”

  The country grew more settled, and we passed through towns. Everywhere we saw overlander trucks parked in front of shacks made of planks and metal. They were small restaurants. Some of them were full-service establishments, offering grilled goat, Tusker beer, a bed, and a woman. Medical doctors who work in East Africa believe that 90 percent of the prostitutes working along the main roads carry the AIDS virus. No one knows for sure, but local doctors think that as many as 30 percent of all men and women of childbearing age who live in the vicinity of Mount Elgon are infected with HIV. Most of them will die of AIDS. Many of their newborn children will also contract AIDS and die of the virus in childhood.

  The emergence of HIV was subtle: it incubates for years in a human host before it kills the host. If the virus had been noticed earlier, it might have been named Kinshasa Highway, in honor of the fact that it passed along the Kinshasa Highway during its emergence from the African forest.

  When I rode along the Kinshasa Highway as a boy, it was a dusty, unpaved thread that wandered through the Rift Valley toward Lake Victoria, carrying not much traffic. It was a gravel road engraved with washboard bumps and broken by occasional pitlike ruts that could crack the frame of a Land Rover. As you drove along it, you would see in the distance a plume of dust growing larger, coming toward you: an automobile. You would move to the shoulder and slow down, and as the car approached, you would place both hands upon the windshield to keep it from shattering if a pebble thrown up by the passing car hit the glass. The car would thunder past, leaving you blinded in yellow fog. Now the road was paved and had a stripe painted down the center, and it carried a continual flow of vehicles. The overlanders were mixed up with pickup trucks and vans jammed with people, and the road reeked of diesel smoke. The paving of the Kinshasa Highway affected every person on earth, and turned out to be one of the most important events of the twentieth century. It has already cost at least ten million lives, with the likelihood that the ultimate number of human casualties will vastly exceed the deaths in the Second World War. In effect, I had witnessed a crucial event in the emergence of AIDS, the transformation of a thread of dirt into a ribbon of tar.

  CAMP

  Robin’s wife, Carrie MacDonald, is his business partner, and she often accompanies him on safaris with clients. The MacDonalds also bring along their two small sons, if the client will allow that. Carrie is in her twenties, with blond hair and brown eyes and a crisp English accent. Her parents brought her to Africa from England when she was a girl.

  We traveled in two Land Rovers, Carrie driving one and Robin driving the other. “We alw
ays take two vehicles in this country, in case one breaks down,” Carrie explained. “It happens literally all the time.” Carrie and Robin’s two boys rode with Carrie. We were also accompanied by three men who were members of the MacDonalds’ safari staff. Their names are Katana Chege, Herman Andembe, and Morris Mulatya. They are professional safari men, and they do most of the work around the campsite. They spoke very little English and had résumés as long as one’s arm. In addition to those people, two friends of mine had joined the expedition. One was a childhood friend named Frederic Grant, and the other was a woman named Jamy Buchanan; both are Americans. I had prepared a written list of instructions for my friends in case I broke with Marburg, and I had sealed the document in an envelope and hidden it in my backpack. It ran for three pages, typewritten, single spaced, describing the signs and symptoms of a filovirus infection in a human being, as well as possible experimental treatments that might arrest the terminal meltdown. I had not told my friends about this envelope, but I planned to give it to them if I came down with a headache. This was a sign of nervousness, to say the least.

  Robin turned into the opposite lane in order to pass a truck, and suddenly we were headed straight for an oncoming car. Its headlights flashed and its horn wailed.

  Fred Grant grabbed the seat and shouted, “Why is this guy coming at us?”

  “Yeah, well, we’re going to die, so don’t worry about it,” Robin remarked. He dodged in front of the truck just in time. He blurted out a song: