The Hot Zone

by Richard Preston

Marburg-virus particles are tough. One would imagine they can survive for a fair amount of time inside a dark cave. Marburg can sit unchanged for at least five days in water. This was shown by Tom Geisbert. One time, just to see what would happen, he put some Marburg particles into flasks of room-temperature water and left the flasks sitting on a countertop for five days (the counter was in Level 4). Then he took the water and dropped it into flasks that contained living monkey cells. The monkey cells filled up with crystalloids, exploded, and died of Marburg. Tom had discovered that five-day-old Marburg-virus particles are just as lethal and infective as fresh particles. Most viruses do not last long outside a host. The AIDS virus survives for only a few minutes when exposed to air. No one has ever tried to see how long Marburg or Ebola can survive while stuck to a dry, surface. Chances are the thread viruses can survive for some time—if the surface is free of sunlight, which would break apart the virus’s genetic material.

  I came to the top of the mound, reached out with my gloved hand, and touched the ceiling. It was studded with brown oblong shapes—petrified tree logs—and whitish fragments—pieces of petrified bone. The rock is solidified ash, the relic of an eruption of Mount Elgon. It is embedded with stone logs, the remains of a tropical rain forest that was swept up in the eruption and buried in ash and mud. The logs are dark brown and shiny, and they reflected opalescent colors in the beam of my head lamp. Some of the logs had fallen out of the roof, leaving holes, and the holes were lined with white crystals. The crystals are made of mineral salts, and they looked evilly sharp. Had Peter Cardinal reached up and touched these crystals? I found bats roosting in the holes among the crystals—insect-eating bats, smaller than the fruit bats that clustered near the cave’s mouth. As I played my head lamp over the holes, bats exploded out of them and whirled around my head and were gone. Then I saw something wonderful. It was the tooth of a crocodile, caught in the rock. The ash flow had buried a river that had contained crocodiles. The crocodiles had been trapped and burned to death in an eruption of Mount Elgon. Full of killers, from the river to the sea.

  I shuffled across razorlike slices of rock that had fallen from the roof, and came to a fresh elephant dropping. It was the size of a small keg of beer. I stepped over it. I came to a crevice and shone my lights down into it. I didn’t see any mummified baby elephants down there. I came to a wall. It was scored with hatch marks—elephant tuskings. The elephants had left scrapes in the rock all over the place. I kept going down and came to a broken pillar. Next to it, a side tunnel continued downward. I wormed into the passage, on my knees. It circled around and came out in the main room. I was boiling hot inside the suit. Drops of moisture had collected on the inside of my faceplate and pooled in the mask under my chin. My footsteps kicked up dust, and it rose in puffs around my boots. It felt strange to be soaking wet and yet wading through dust. As I was climbing out of the passage, my head slammed against a rock. If I hadn’t been wearing protective gear, the rock would have cut my scalp. It seemed easy to get a head wound in the cave. Perhaps that was the route of infection: the virus clings to the rocks and gets into the bloodstream through a cut.

  I proceeded deeper until I came to a final wall in the throat of the cave. There, at knee level, in total darkness, I found spiders living in webs. They had left their egg cases scattered about, hanging from the rock. The spiders were carrying on their life cycle at the back of Kitum Cave. That meant they were finding something to eat in the darkness, something that was flying into their webs. I had seen moths and winged insects pouring from the mouth of the cave, and it occurred to me that some of them must be flying all the way to the back. The spiders could be the host. They could catch the virus from an insect in their diet. Perhaps Marburg cycles in the blood of spiders. Perhaps Monet and Cardinal were bitten by spiders. You feel a cobweb clinging to your face and then comes a mild sting, and after that you don’t feel anything. You can’t see it, you can’t smell it, you can’t feel it. You don’t know it’s there until you start to bleed.

  So much was happening that I didn’t understand. Kitum Cave plays a role in the life of the forest, but what the role is no one can say. I found a crevice that seemed to be full of clear, deep water. It couldn’t be water, I thought, the crevice must be dry. I picked up a stone and threw it. Halfway down in its flight, the stone made a splash. It had hit water. The stone spun lazily downward into the crevice and out of sight, and ripples spread across the pool and died away, throwing reflections of my head lamp onto the wall of the cave.

  I climbed over fallen plates of stone back to the top of the rubble pile, playing my lights around. The room was more than a hundred yards across, larger in all directions than a football field. My lights failed to penetrate to the edges of the room, and the edges descended downward into darkness on all sides. The mound of rubble in the center made the cave resemble the curving roof of a mouth. As you look into someone’s mouth, you see the tongue in front, lying under the roof of the mouth, and you see the tongue curving backward and down into the throat: that is what Kitum Cave looked like. Say “Ahh,” Kitum Cave. Do you have a virus? No instruments, no senses can tell you if you are in the presence of the predator. I turned off my lights and stood in total darkness, feeling a bath of sweat trickle down my chest, hearing the thump of my heart and the swish of blood in my head.

  The afternoon rains had come. Fred Grant was standing inside the mouth of the cave to keep himself dry. The askari sat on a rock nearby, bouncing the machine gun on his knees, looking bored.

  “Welcome back,” Grant said. “Was it good for you?”

  “We’ll find out in seven days,” I said.

  He scrutinized me. “There appear to be splatters on your face shield.”

  “Splatters of what?”

  “Looks like water.”

  “It’s just sweat inside my mask. If you’ll bear with me a moment, I’m going to get this suit off.” I took a plastic laundry tub—part of the gear we had carried up to the cave—and left it under the waterfall for a moment. When the tub was partly full, I carried it over to the elephants’ pathway, at the entrance, put it on the ground, and poured in most of a gallon of “bloody Jik”—laundry bleach.

  I stepped into the tub. My boots disappeared in a swirl of dirt coming off them, and the Jik turned brown. I put my gloved hands into the brown Jik, scooped up some of the liquid, and poured it over my head and face mask. Using a toilet brush, I scrubbed my boots and legs to remove obvious patches of dirt. I dropped my bagged map into the Jik. I dropped my flashlight and head lamp into the Jik. I took off my face mask and dunked it, along with the purple filters. Then my eyeglasses went into the Jik.

  I peeled off my green gauntlet gloves. They went into the Jik. I stepped out of my Tyvek suit, peeling the sticky tape as I went. The whole suit, together with the yellow boots, went into the Jik. It was a stew of biohazard gear.

  Underneath my suit, I wore a set of clothes and a pair of sneakers. I stripped to the skin and put the clothing into a plastic garbage bag—a so-called hot bag—along with a splash or two of Jik, and then put that bag into another bag. I washed the outsides of both bags with bleach. From my backpack, I removed a clean set of clothing and put it on. I put the biohazard gear into double bags, adding Jik.

  Robin MacDonald appeared noiselessly in his sneakers at the top of the rocks at the mouth of the cave. “Sir Bat Shit!” he called. “How did it go?”

  We walked down the trail, lugging the hot bags, and returned to camp. The rain intensified. We settled down on chairs in the mess tent with a bottle of scotch whisky, while the rain splattered down and hissed through the leaves. It was three o’clock in the afternoon. The clouds thickened to the point where the sky grew black, and we lighted oil lamps inside the mess tent. Peals of thunder rolled around the mountain, and the rain turned into a downpour.

  Robin settled into a folding chair. “Ah, man, this rain never stops on Elgon. This happens all year round.”

  There was a stroboscopic flash and a
bang, and a lightning bolt whacked an olive tree. The flash outlined his face, his glasses. We chased the scotch with Tusker beers and played a round of poker. Robin declined to join the game. I had the impression he didn’t know how to play poker.

  “Have some whisky, Robin,” Fred Grant said to him.

  “None of that for me,” he said. “My stomach doesn’t like it. Beer is just right. It gives you protein, and you sleep well.”

  The rain tapered off, and the clouds momentarily lightened. Olive trees arched overhead in squiggles, their feet sunk in shadows. Water drops fell through the halls of trees. Mousebirds gave off flutelike cries, and then the cries stopped, and Mount Elgon became silent. The forest shifted gently, rocking back and forth. Rain began to fall again.

  “How are you feeling, Sir Bat Shit?” Robin said. “Are you getting any mental symptoms? That’s when you first start talking to yourself in the toilet. It’ll be starting any day now.”

  The mental symptoms were starting already. I remembered slamming my head into the roof of the cave. That had raised a bump on my scalp. There would be microscopic tears in the skin around that bump. I had begun to understand the feeling of having been exposed to a filovirus: I’ll be okay. No problem. The odds are very good that I wasn’t exposed to anything.

  The emergence of AIDS, Ebola, and any number of other rain-forest agents appears to be a natural consequence of the ruin of the tropical biosphere. The emerging viruses are surfacing from ecologically damaged parts of the earth. Many of them come from the tattered edges of tropical rain forest, or they come from tropical savanna that is being settled rapidly by people. The tropical rain forests are the deep reservoirs of life on the planet, containing most of the world’s plant and animal species. The rain forests are also its largest reservoirs of viruses, since all living things carry viruses. When viruses come out of an ecosystem, they tend to spread in waves through the human population, like echoes from the dying biosphere. Here are the names of some emerging viruses: Lassa. Rift Valley. Oropouche. Rocio. Q. Guanarito. VEE. Monkeypox. Dengue. Chikungunya. The hantaviruses. Machupo. Junin. The rabieslike strains Mokola and Duvenhage. LeDantec. The Kyasanur Forest brain virus. Then there is HIV—which is very much an emerging virus, because its penetration of the human species is increasing rapidly, with no end in sight. The Semliki Forest agent. Crimean-Congo. Sindbis. O’nyongnyong. Nameless São Paulo. Marburg. Ebola Sudan. Ebola Zaire. Ebola Reston.

  In a sense, the earth is mounting an immune response against the human species. It is beginning to react to the human parasite, the flooding infection of people, the dead spots of concrete all over the planet, the cancerous rot-outs in Europe, Japan, and the United States, thick with replicating primates, the colonies enlarging and spreading and threatening to shock the biosphere with mass extinctions. Perhaps the biosphere does not “like” the idea of five billion humans. Or it could also be said that the extreme amplification of the human race, which has occurred only in the past hundred years or so, has suddenly produced a very large quantity of meat, which is sitting everywhere in the biosphere and may not be able to defend itself against a life form that might want to consume it. Nature has interesting ways of balancing itself. The rain forest has its own defenses. The earth’s immune system, so to speak, has recognized the presence of the human species and is starting to kick in. The earth is attempting to rid itself of an infection by the human parasite. Perhaps AIDS is the first step in a natural process of clearance.

  AIDS is arguably the worst environmental disaster of the twentieth century. The AIDS virus may well have jumped into the human race from African primates, from monkeys and anthropoid apes. For example, HIV-2 (one of the two major strains of HIV) may be a mutant virus that jumped into us from an African monkey known as the sooty mangabey, perhaps when monkey hunters or trappers touched bloody tissue, HIV-1 (the other strain) may have jumped into us from chimpanzees—perhaps when hunters butchered chimpanzees. A strain of simian AIDS virus was recently isolated from a chimpanzee in Gabon, in West Africa, which is, so far, the closest thing to HIV-1 that anyone has yet found in the animal kingdom.

  The AIDS virus was first noticed in 1980 in Los Angeles by a doctor who realized that his gay male patients were dying of an infectious agent. If anyone at the time had suggested that this unknown disease in gay men in southern California came from wild chimpanzees in Africa, the medical community would have collectively burst out laughing. No one is laughing now. I find it extremely interesting to consider the idea that the chimpanzee is an endangered rain-forest animal and then to contemplate the idea that a virus that moved from chimps into us is suddenly not endangered at all. You could say that rain-forest viruses are extremely good at looking after their own interests.

  The AIDS virus is a fast mutator; it changes constantly. It is a hypermutant, a shape shifter, spontaneously altering its character as it moves through populations and through individuals. It mutates even in the course of one infection, and a person who dies of HIV is usually infected with multiple strains, which have all arisen spontaneously as mutants in the body. The fact that the virus mutates rapidly means that vaccines for it will be very difficult to develop. In a larger sense, it means that the AIDS virus is a natural survivor of changes in ecosystems. The AIDS virus and other emerging viruses are surviving the wreck of the tropical biosphere because they can mutate faster than any changes taking place in their ecosystems. They must be good at escaping trouble, if some of them have been around for as long as four billion years. I tend to think of rats leaving a ship.

  I suspect that AIDS might not be Nature’s preeminent display of power. Whether the human race can actually maintain a population of five billion or more without a crash with a hot virus remains an open question. Unanswered. The answer lies hidden in the labyrinth of tropical ecosystems. AIDS is the revenge of the rain forest. It may be only the beginning.

  No problem, I thought. Of course, I’ll be all right. We’ll be all right. No problem at all. Everything will be all right. Plenty of people have gone inside Kitum Cave without becoming sick. Three to eighteen days. As the amplification begins, you feel nothing. It made me think of Joe McCormick, the C.D.C. official who had clashed with the Army over the management of the Ebola Reston outbreak. I remembered the story of him in Sudan, hunting Ebola virus. At the end of a plane flight into deep bush, he had come face to face with Ebola in a hut full of dying patients, had pricked his thumb with a bloody needle, and got lucky, and had survived the experience. In the end, Joe McCormick had been right about the Ebola Reston virus: it had not proved to be highly infectious in people. Then I thought about another Joe McCormick discovery, one of the few breakthroughs in the treatment of Ebola virus. In Sudan, thinking he was going to die of Ebola, he had discovered that a bottle of Scotch is the only good treatment for exposure to a filovirus.

  I drove to the abandoned monkey house one day in autumn, to see what had become of it. It was a warm day in Indian summer. A brown haze hung over Washington. I turned off the Beltway and approached the building discreetly. The place was deserted and as quiet as a tomb. Out front, a sweet-gum tree dropped an occasional leaf. FOR LEASE signs sat in front of many of the offices around the parking lot. I sensed the presence not of a virus but of financial illness—clinical signs of the eighties, like your skin peeling off after a bad fever. I walked across the grassy area behind the building until I reached the Army’s insertion point, a glass door. It was locked. Shreds of silver duct tape dangled from the door’s edges. I looked inside and saw a floor mottled with reddish brown stains. A sign on the wall said CLEAN UP YOUR OWN MESS. Next to it, I discerned the air-lock corridor, the gray zone through which the soldiers had passed into the hot zone. It had gray cinder-block walls: the ideal gray zone.

  My feet rustled through shreds of plastic in the grass. I found elderberries ripening around a rusted air-handling machine. I heard a ball bounce, and saw a boy dribbling a basketball on a playground. The ball cast rubbery echoes off the former monkey
house. Children’s shouts came from the day-care center through the trees. Exploring the back of the building, I came to a window and looked in. Climbing vines had grown up inside the room and had pressed against the glass of the windows, seeking warmth and light. Where had those vines found water inside the building? The vine was Tartarian honeysuckle, a weed that grows in waste places and on abandoned ground. The flowers of Tartarian honeysuckle have no smell. That is, they smell like a virus; and they flourish in ruined habitats. Tartarian honeysuckle reminded me of Tartarus, the land of the dead in Virgil’s Aeneid, the underworld, where the shades of the dead whispered in the shadows.

  I couldn’t see through the tangled vines into the former hot zone. It was like looking into a rain forest. I walked around to the side of the building and found another glass door beribboned with tape. I pressed my nose against the glass and cupped my hands around my eyes to stop reflections, and saw a bucket smeared with a dry brown crust. The crust looked like dried monkey excrement. Whatever it was, I guessed it had been stirred up with Clorox bleach. A spider had strung a web between a wall and the bucket of waste. On the floor under the web, the spider had dropped husks of flies and yellow jackets. The time of year being autumn, the spider had left egg cases in its web, preparing for its own cycle of replication. Life had established itself in the monkey house. Ebola had risen in these rooms, flashed its colors, fed, and subsided into the forest. It will be back.

  MAIN CHARACTERS

  IN ORDER OF APPEARANCE

  (Military rank given as of the time of the Reston event.)

  “CHARLES MONET.” A French expatriate living in western Kenya. In January 1980, he essentially melts down with Marburg virus while traveling on an airplane.

  LIEUTENANT COLONEL NANCY JAAX. Veterinary pathologist at USAMRIID. Begins working with Ebola virus in 1983, when she gets a hole in her space-suit glove. Becomes chief of pathology at USAMRIID in 1989, and during the winter of that year becomes a player in the Reston biohazard operation.