The Hot Zone

by Richard Preston

  Meanwhile, he was surprised at how calm his wife seemed. He would have flown home that night if he had perceived any inkling of distress in her.

  The Ebola experiments were not a success in the sense that the drugs had no effect on the virus. All of Gene Johnson’s infected monkeys died no matter what drugs they were given. They all died. The virus absolutely nuked the monkeys. It was a complete slate wiper. The only survivors of the experiment were the two control monkeys—the healthy, uninfected monkeys that lived in cages across the room from the sick monkeys. The control monkeys had not been infected with Ebola, and so, as expected, they had not become sick.

  Then, two weeks after the incident with the bloody glove, something frightening happened in the Ebola rooms. The two healthy monkeys developed red eyes and bloody noses, and they crashed and bled out. They had never been deliberately infected with Ebola virus, and they had not come near the sick monkeys. They were separated from the sick monkeys by open floor.

  If a healthy person were placed on the other side of a room from a person who was sick with AIDS, the AIDS virus would not be able to drift across the room through the air and infect the healthy person. But Ebola had drifted across a room. It had moved quickly, decisively, and by an unknown route. Most likely the control monkeys inhaled it into their lungs. “It got there somehow,” Nancy Jaax would say to me as she told me the story some years later. “Monkeys spit and throw stuff. And when the caretakers wash the cages down with water hoses, that can create an aerosol of droplets. It probably traveled through the air in aerosolized secretions. That was when I knew that Ebola can travel through the air.”

  EBOLA RIVER

  1976 SUMMER-AUTUMN

  On July 6, 1976, five hundred miles northwest of Mount Elgon, in southern Sudan, near the fingered edge of the central-African rain forest, a man who is known to Ebola hunters as Yu. G. went into shock and died with blood running from the orifices of his body. He is referred to only by his initials. Mr. Yu. G. was the first identified case, the index case, in an outbreak of an unknown virus.

  Mr. Yu. G. was a storekeeper in a cotton factory in the town of Nzara. The population of Nzara had grown in recent years—the town had experienced, in its own way, the human population explosion that is occurring throughout the equatorial regions of the earth. The people of that area in southern Sudan are the Zande, a large tribe. The country of the Zande is savanna mixed with riverine forest, beautiful country, where acacia trees cluster along the banks of seasonal rivers. African doves perch in the trees and call their drawn-out calls. The land between the rivers is a sea of elephant grass, which can grow ten feet high. As you head south, toward Zaire, the land rises and forms hills, and the forest begins to spread away from the rivers and thickens into a closed canopy, and you enter the rain forest. The land around the town of Nzara held rich plantations of teak and fruit trees and cotton. People were poor, but they worked hard and raised large families and kept to their tribal traditions.

  Mr. Yu. G. was a salaried man. He worked at a desk in a room piled with cotton cloth at the back of the factory. Bats roosted in the ceiling of the room near his desk. If the bats were infected with Ebola, no one has been able to prove it. The virus may have entered the cotton factory by some unknown route—perhaps in insects trapped in the cotton fibers, for example, or in rats that lived in the factory. Or, possibly, the virus had nothing to do with the cotton factory, and Mr. Yu. G. was infected somewhere else. He did not go to a hospital, and died on a cot in his family compound. His family gave him a traditional Zande funeral and left his body under a mound of stones in a clearing of elephant grass. His grave has been visited more than once by doctors from Europe and America, who want to see it and reflect on its meaning, and pay their respects to the index case of what later became known as Ebola Sudan.

  He is remembered today as a “quiet, unremarkable man.” No photograph was taken of him during his lifetime, and no one seems to remember what he looked like. He wasn’t well known, even in his hometown. They say that his brother was tall and slender, so perhaps he was, too. He passed through the gates of life unnoticed by anyone except his family and a few of his co-workers. He might have made no difference except for the fact that he was a host.

  His illness began to copy itself. A few days after he died, two other salaried men who worked at desks near him in the same room broke with bleeding, went into shock, and died with massive hemorrhages from the natural openings of the body. One of the dead men was a popular fellow known as P. G. Unlike the quiet Mr. Yu. G., he had a wide circle of friends, including several mistresses. He spread the agent far and wide in the town. The agent jumped easily from person to person, apparently through touching and sexual contact. It was a fast spreader, and it could live easily in people. It passed through as many as sixteen generations of infection as it jumped from person to person in Sudan. It also killed many of its hosts. While this is not necessarily in the best interest of the virus, if the virus is highly contagious, and can jump fast enough from host to host, then it does not matter, really, what happens to the previous host, because the virus can amplify itself for quite a while, at least until it kills off much of the population of hosts. Most of the fatal cases of Ebola Sudan can be traced back through chains of infection to the quiet Mr. Yu. G. A hot strain radiated out of him and nearly devastated the human population of southern Sudan. The strain burned through the town of Nzara and reached eastward to the town of Maridi, where there was a hospital.

  It hit the hospital like a bomb. It savaged patients and snaked like chain lightning out from the hospital through patients’ families. Apparently the medical staff had been giving patients injections with dirty needles. The virus jumped quickly through the hospital via the needles, and then it hit the medical staff. A characteristic of a lethal, contagious, and incurable virus is that it quickly gets into the medical people. In some cases, the medical system may intensify the outbreak, like a lens that focuses sunlight on a heap of tinder.

  The virus transformed the hospital at Maridi into a morgue. As it jumped from bed to bed, killing patients left and right, doctors began to notice signs of mental derangement, psychosis, depersonalization, zombie-like behavior. Some of the dying stripped off their clothes and ran out of the hospital, naked and bleeding, and wandered through the streets of the town, seeking their homes, not seeming to know what had happened or how they had gotten into this condition. There is no doubt that Ebola damages the brain and causes psychotic dementia. It is not easy, however, to separate brain damage from the effects of fear. If you were trapped in a hospital where people were dissolving in their beds, you might try to escape, and if you were a bleeder and frightened, you might take off your clothes, and people might think you had gone mad.

  The Sudan strain was more than twice as lethal as Marburg virus—its case-fatality rate was 50 percent. That is, fully half of the people who came down with it ended up dying, and quickly. This was the same kind of fatality rate as was seen with the black plague during the Middle Ages. If the Ebola Sudan virus had managed to spread out of central Africa, it might have entered Khartoum in a few weeks, penetrated Cairo a few weeks after that, and from there it would have hopped to Athens, New York, Paris, London, Singapore—it would have gone everywhere on the planet. Yet that never happened, and the crisis in Sudan passed away unnoticed by the world at large. What happened in Sudan could be compared to the secret detonation of an atomic bomb. If the human race came close to a major biological accident, we never knew it.

  For reasons that are not clear, the outbreak subsided, and the virus vanished. The hospital at Maridi had been the epicenter of the emergence. As the virus ravaged the hospital, the surviving medical staff panicked and ran off into the bush. It was probably the wisest thing to do and the best thing that could have happened, because it stopped the use of dirty needles and emptied the hospital, which helped to break the chain of infection.

  There was another possible reason why the Ebola Sudan virus vanished. It was ex
ceedingly hot. It killed people so fast that they didn’t have much time to infect other people before they died. Furthermore, the virus was not airborne. It was not quite contagious enough to start a full-scale disaster. It traveled in blood, and the bleeding victim did not touch very many other people before dying, and so the virus did not have many chances to jump to a new host. Had people been coughing the virus into the air … it would have been a different story. In any case, the Ebola Sudan virus destroyed a few hundred people in central Africa the way a fire consumes a pile of straw—until the blaze burns out at the center and ends in a heap of ash—rather than smoldering around the planet, as AIDS has done, like a fire in a coal mine, impossible to put out. The Ebola virus, in its Sudan incarnation, retreated to the heart of the bush, where undoubtedly it lives to this day, cycling and cycling in some unknown host, able to shift its shape, able to mutate and become a new thing, with the potential to enter the human species in a new form.

  Two months after the start of the Sudan emergence—the time was now early September 1976—an even more lethal filovirus emerged five hundred miles to the west, in a district of northern Zaire called Bumba Zone, an area of tropical rain forest populated by scattered villages and drained by the Ebola River. The Ebola Zaire strain was nearly twice as lethal as Ebola Sudan. It seemed to emerge out of the stillness of an implacable force brooding on an inscrutable intention. To this day, the first human case of Ebola Zaire has never been identified.

  In the first days of September, some unknown person who probably lived somewhere to the south of the Ebola River perhaps touched something bloody. It might have been monkey meat—people in that area hunt monkeys for food—or it might have been the meat of some other animal, such as an elephant or a bat. Or perhaps the person touched a crushed insect, or perhaps he or she was bitten by a spider. Whatever the original host of the virus, it seems that a blood-to-blood contact in the rain forest enabled the virus to move into the human world. The portal into the human race may well have been a cut on this unknown person’s hand.

  The virus surfaced in the Yambuku Mission Hospital, an upcountry clinic run by Belgian nuns. The hospital was a collection of corrugated tin roofs and whitewashed concrete walls sitting beside a church in the forest, where bells rang and you heard a sound of hymns and the words of the high mass spoken in Bantu. Next door, people stood in line at the clinic and shivered with malaria while they waited for a nun to give them an injection of medicine that might make them feel better.

  The mission in Yambuku also ran a school for children. In late August, a teacher from the school and some friends went on a vacation trip to the northern part of Zaire. They borrowed a Land Rover from the mission to make their journey. and they explored the country as they headed northward, moving slowly along rutted tracks, no doubt getting stuck in the mud from time to time, which is the way things go when you try to drive through Zaire. The track was mostly a footpath enclosed by a canopy of trees, and it was always in shadow, as if they were driving through a tunnel. Eventually they came to the Ebola River and crossed it on a ferry barge and continued northward. Near the Obangui River, they stopped at a roadside market, where the schoolteacher bought some fresh antelope meat. One of his friends bought a freshly killed monkey and put it in the back of the Land Rover. Any of the friends could have handled the monkey or the antelope meat while they were bouncing around in the Land Rover.

  They turned back, and when the schoolteacher arrived home, his wife stewed the antelope meat, and everyone in the family ate it. The following morning he felt unwell, and so before he reported to his teaching job at the school, he stopped off at the Yambuku Hospital, on the other side of the church, to get an injection of medicine from the nuns.

  At the beginning of each day, the nuns at Yambuku Hospital would lay out five hypodermic syringes on a table, and they would use them to give shots to patients all day long. They were using five needles a day to give injections to hundreds of people in the hospital’s outpatient and maternity clinics. The nuns and staff occasionally rinsed the needles in a pan of warm water after an injection, to get the blood off the needle, but more often they proceeded from shot to shot without rinsing the needle, moving from arm to arm, mixing blood with blood. Since Ebola virus is highly infective and since as few as five or ten particles of the virus in a blood-borne contact can start an extreme amplification in a new host, there would have been excellent opportunity for the agent to spread.

  A few days after the schoolteacher received his injection, he broke with Ebola Zaire. He was the first known case of Ebola Zaire, but he may well have contracted the virus from a dirty needle during his injection at the hospital, which means that someone else might have previously visited the hospital while sick with Ebola virus and earlier in the day received an injection from the same needle that was then used on the schoolteacher. That unknown person probably stood in line for an injection just ahead of the schoolteacher. That person would have started the Ebola outbreak in Zaire. As in Sudan, the emergence of a life form that could in theory have gone around the earth began with one infected person.

  The virus erupted simultaneously in fifty-five villages surrounding the hospital. First it killed people who had received injections, and then it moved through families, killing family members, particularly women, who in Africa prepare the dead for burial. It swept through the Yambuku Hospital’s nursing staff, killing most of the nurses, and then it hit the Belgian nuns. The first nun to break with Ebola was a midwife who had delivered a stillborn child. The mother was dying of Ebola and had given the virus to her unborn baby. The fetus had evidently crashed and bled out inside the mother’s womb. The woman then aborted spontaneously, and the nun who assisted at this grotesque delivery came away from the experience with blood on her hands. The blood of the mother and fetus was radiantly hot, and the nun must have had a small break or cut on the skin of her hands. She developed an explosive infection and was dead in five days.

  There was a nun at the Yambuku Hospital who is known today as Sister M. E. She became gravely ill with l’épidémie, or “the epidemic,” as they had begun to call it. A priest at Yambuku decided to try to take her to the city of Kinshasa, the capital of Zaire, in order to get her better medical treatment. He and another nun, named Sister E. R., drove Sister M. E. in a Land Rover to the town of Bumba, a sprawl of cinder blocks and wooden shacks that huddles beside the Congo River. They went to the airfield at Bumba and hired a small plane to fly them to Kinshasa, and when they reached the city, they took Sister M. E. to Ngaliema Hospital, a private hospital run by Swedish nurses, where she was given a room of her own. There she endured her agonals and committed her soul to Christ.

  • • •

  Ebola Zaire attacks every organ and tissue in the human body except skeletal muscle and bone. It is a perfect parasite because it transforms virtually every part of the body into a digested slime of virus particles. The seven mysterious proteins that, assembled together, make up the Ebola-virus particle, work as a relentless machine, a molecular shark, and they consume the body as the virus makes copies of itself. Small blood clots begin to appear in the bloodstream, and the blood thickens and slows, and the clots begin to stick to the walls of blood vessels. This is known as pavementing, because the clots fit together in a mosaic. The mosaic thickens and throws more clots, and the clots drift through the bloodstream into the small capillaries, where they get stuck. This shuts off the blood supply to various parts of the body, causing dead spots to appear in the brain, liver, kidneys, lungs, intestines, testicles, breast tissue (of men as well as women), and all through the skin. The skin develops red spots, called petechiae, which are hemorrhages under the skin. Ebola attacks connective tissue with particular ferocity; it multiplies in collagen, the chief constituent protein of the tissue that holds the organs together. (The seven Ebola proteins somehow chew up the body’s structural proteins.) In this way, collagen in the body turns to mush, and the underlayers of the skin die and liquefy. The skin bubbles up into
a sea of tiny white blisters mixed with red spots known as a maculopapular rash. This rash has been likened to tapioca pudding. Spontaneous rips appear in the skin, and hemorrhagic blood pours from the rips. The red spots on the skin grow and spread and merge to become huge, spontaneous bruises, and the skin goes soft and pulpy, and can tear off if it is touched with any kind of pressure. Your mouth bleeds, and you bleed around your teeth, and you may have hemorrhages from the salivary glands—literally every opening in the body bleeds, no matter how small. The surface of the tongue turns brilliant red and then sloughs off, and is swallowed or spat out. It is said to be extraordinarily painful to lose the surface of one’s tongue. The tongue’s skin may be torn off during rushes of the black vomit. The back of the throat and the lining of the windpipe may also slough off, and the dead tissue slides down the windpipe into the lungs or is coughed up with sputum. Your heart bleeds into itself; the heart muscle softens and has hemorrhages into its chambers, and blood squeezes out of the heart muscle as the heart beats, and it floods the chest cavity. The brain becomes clogged with dead blood cells, a condition known as sludging of the brain. Ebola attacks the lining of the eyeball, and the eyeballs may fill up with blood: you may go blind. Droplets of blood stand out on the eyelids: you may weep blood. The blood runs from your eyes down your cheeks and refuses to coagulate. You may have a hemispherical stroke, in which one whole side of the body is paralyzed, which is invariably fatal in a case of Ebola. Even while the body’s internal organs are becoming plugged with coagulated blood, the blood that streams out of the body cannot clot; it resembles whey being squeezed out of curds. The blood has been stripped of its clotting factors. If you put the runny Ebola blood in a test tube and look at it, you see that the blood is destroyed. Its red cells are broken and dead. The blood looks as if it has been buzzed in an electric blender.