Lisa Henley is of medium height, with hazel eyes and dark brown hair that she' usually wears tied back in a ponytail; when she's working m the laboratory, she ties her hair up so that it won't fall into her experiments. She has an open face, a calm, unruffled manner, and a rapid, precise way of speaking. She was an All-American varsity-lacrosse player at Johns Hopkins, and she has broad shoulders and an athletic way of moving. She usually wears khaki slacks, square-toed loafers, and gold earrings decorated with small pearls. She rarely takes off the earrings, even when she's inside a biohazard s.p.a.ce suit. Hensley is a scuba diver, and she likes to dive on wrecks and into underwater caves. Cave diving is not for people who get claustrophobia, and the sport has a high rate of accidents. She finds it calming, she says.

Lisa's father, Dr. Michael Hensley, works in the pharmaceutical industry. When he was younger, Mike Hensley rode horseback and fenced with sabers, but during his medical internship he had what he describes as an interesting event-a hemorrhage. He learned that he had a mild form of hemophilia, a genetic disease that occurs only in men but is inherited through female carriers. Hemophilia ran in the Hensley family. Many men with hemophilia have died of AIDS, having received blood transfusions tainted with HIV during the years when blood wasn't tested for it.

When Lisa was eight years old, HIV was just beginning to be understood. Mike Hensley received blood transfusions during that time, but he didn't become infected. Lisa was extremely close to her father. He took her into his laboratory and taught her how to grow bacteria on petri dishes, and he gave her bottles of seawater to look at in his microscopes. She saw that a tiny droplet of the sea was an ecosystem packed with life. She told her parents that she wanted to be a marine biologist, and at twelve she was certified as a diver.

In high school, she was a jock who was bored out of her mind with her studies, including biology.

She became a state-champion lacrosse goalie with a string of varsity letters, and applied to the U.S.

Naval Academy to become an aviator. Then, at the last minute, she changed her mind and went to Johns Hopkins, which recruited her to play lacrosse.

At Johns Hopkins, Hensley began taking courses in public health. When she was a junior, Mike Hensley invited her to attend a scientific conference in San Francisco on HIV, and it electrified her. She became fascinated with the idea that if you really understood how viruses emerge, you might be able to stop a disease like AIDS before it could spread. She graduated from Johns Hopkins in four years with a master's degree in public health.

Hensley went on to get a Ph.D. in epidemiology and microbiology in three years at the University of North Carolina at Chapel Hill, and at the same time she got a second master's degree in public health.

She had pretty much no social life in graduate school and devoted herself to the laboratory. She moved viruses from one type of host to another and watched trans-species jumps occur in the lab, before her eyes. She learned the standard methods of virus engineering-how to change the genes of a virus, altering the strain.

Hensley had an apartment across the street from her lab at Chapel Hill, so that she could spend nearly every waking minute in the lab, with the goal of having three advanced degrees by her twenty-fifth birthday. She didn't sleep much, and when she did she had recurrent dreams, focused on her hands. In the dreams, she was working faster and faster, trying to finish an experiment, yet she could never make her hands go fast enough.... She was falling behind.... Her grant money was running out.... Life was too short.... And she would wake up. She'd grab a Diet c.o.ke for breakfast and stumble across the street to the lab, where she would work all day and half the night.

At USAMRIID, Lisa Hensley began doing research on SHF, a Level 3 virus that is harmless to humans but is devastating to monkeys. It was a virus that could emerge as a human disease someday.

Her social life had opened up, and she had begun dating a virologist at the National Inst.i.tutes of Health in Bethesda, Maryland. Things didn't work out well between them. The problem was that when they argued with each other, it was about viruses. Scientific people are compet.i.tive types, and they like to be right. Any sort of discussion about viruses with her friend could turn into an emotional fight. One time, they were in his apartment debating some minor point about a virus, and he said, "You're wrong about that." She went over to a shelf, grabbed a textbook, and opened it to the page that showed she was right.

She placed it on the kitchen table and walked out. Hensley admitted to herself that this was perhaps not emotionally shrewd. When they broke up, he vowed to herself, No more scientists, they're a headache.

The head of Lisa Hensley's division at USAMRIID was Colonel Nancy Jaax, an experienced pathologist with a strong interest in Ebola virus. Hensley had zero interest in Ebola. The s.p.a.ce suits at USAMRIID are blue, and from the day she arrived there Hensley made a point of sayng, "The people who work in the blue suits are nuts. I'm not putting on a blue suit for Ebola. You have to be crazy to do that."

Nancy Jaax heard about Hensley's cracks about people who worked with Ebola being crazy. It was felt that cautious people would be less likely to have an accident in Level 4. The last thing anyone wanted was a researcher getting c.o.c.ky around a hot agent.

One day Hensley walked into a regular staff meeting, in a windowless conference room on the second floor of the Inst.i.tute, and, as a junior scientist, took her place at the foot of the table. The meeting droned on for a while, typically, until Nancy Jaax suddenly looked down the table at Hensley and announced that her mission was about to change. "I'm going to have you refocus your efforts, Lisa," Jaax said. "We'll get you trained in the blue suits, and we'll start you working with Ebola Zaire."

Lisa Hensley came out of the meeting feeling dizzy and a little unsteady on her feet. She teetered back to her cubicle and fell into a chair. The cubicle was a cluttered s.p.a.ce, piled with papers. There was a computer, a stereo, and pictures of her mother and father and other members of her family.

They're going to start me with Ebola Zaire? she thought.

Death from Ebola comes about five to nine days after you break out with symptoms, and it occurs with spurts of blood coming from the orifices and a collapse of blood pressure, an event that Army people call the crash and bleed-out. In some cases, the virus causes a near-total loss of blood-an Ebola exsanguination. They were paying Hensley thirty-eight thousand dollars a year, but was it worth it?

If you infected yourself with Ebola, that was it.

Hensley was closer to her parents than to anyone else in the world. Her mother, Karen, called her three times a week to find out how things were going. Lisa told her that the powers at the Inst.i.tute had redirected her career into Ebola virus.

"You're going into a BL-4 suite to work with Ebola? Isn't there anything else they could have you do?"

Lisa tried to play things down. "Oh, Mother. I'm much safer in a s.p.a.ce suit. Really."

"Mike! Mike! Come talk to your daughter."

Lisa's father thought it was a good opportunity for her, and they decided to give Karen a tour of the laboratories, so she could see that everything was safe.

The tour wasn't quite as successful as they had hoped. Karen Hensley is an economist, and she didn't have a natural feel for biohazard containment. She noticed a door marked CRASH DOOR.' That didn't sound too good, but it was a safety feature. If a fire or other emergency occurs in Level 4, you can burst out through the crash door, and you end up standing in the hallway in your s.p.a.ce suit. (So far, no crash door has been used for that purpose at USAMRIID.) What really bothered her was the fact that the edges of the crash door were sealed with brown duct tape, which ran all around the door frame.

"Why do they have tape around that door, Lisa? Is that how they seal the doors around here? Just with tape?"

Lisa explained to her mother that the hot suites were under negative air pressure, and air was constantly flowing into the labs, so the tape was actually to prevent dust and contaminants from entering and messing up the experiments.

Karen Hensley didn't like the look of the tape, period. Then she discovered what you wear inside a biohazard s.p.a.ce suit: green cotton surgical scrubs, latex surgical gloves, and socks. That is all.

Underwear is forbidden in a hot lab. Karen Hensley was mortified for her daughter. She could not imagine why they would make any woman work in a laboratory without a bra.

Hensley was trained in blue-suit work by an older postdoc at USAMRIID named Steven J.

Hatfill, a big, muscular man in his forties with a mustache and a medical degree-a civilian medical doctor with a background in the U.S. Special Forces. He showed her how to put on the suit, how to do a safety check on it for leaks, how to maintain it properly, and how to go in and out through the decon-shower air lock m Level 4. Steve Hatfill was known around the Inst.i.tute as a "blue-suit cowboy."

He seemed fearless in a blue suit, and he thrived in Level 4. He had a thirst for adventure: he had been a soldier in Africa, where he said he had served in Rhodesia with the white Rhodesian Special Air Squadron-the SAS-during the years when black insurgents were trying to overthrow Rhodesia's white government. Later, he got a medical degree in Zimbabwe, and he worked as a doctor in Antarctica for a year and a half with a team of South African scientists. Hatfill had become convinced that a bioterror event was likely to happen. He served as a consultant to emergency planners in New York City, and he kept a scrip of reflective tape on the roof of his car, so that in the event of a bioemergency the state-police helicopters could find him.

Lisa Hensley found Steve Hatfill likable and entertaining, quite a character. He was bright, a super lab worker, and he taught her some techniques. He was researching the coagulation of monkey blood infected with Ebola virus. Ebola blood became hemorrhagic and wouldn't coagulate, but it needed to be clotted in the lab for study; he taught her how to do this. He had all kinds of gadgets running in Level 4-a.s.say machines, that sort of thing.

During one of her first training sessions, Hensley looked over at Hatfill and noticed that he was hunched inside his s.p.a.ce suit. One arm of his sutt was hanging limp, as if he had had a stroke. At first, she didn't know what was going on: was he suffocating or what? Hatfill had pulled his arm up inside the sleeve of his s.p.a.ce suit, and he was eating a candy bar.

Lisa Hensley was a rising star at the Inst.i.tute. Postdocs like her tended to move on quickly if they got bored, and she was a.s.signed to work in Peter Jahrling's group. Despite his growing involvement with smallpox and national policy, Jahrling had continued to do research into Ebola virus, working closely with Tom Geisbert. They not only were scientific collaborators but had become personal friends. Lisa Hensley went to work for Geisbert, who was running Ebola experiments in Level 4. She did lab work on samples of monkey blood infected with Ebola. On her own, she began developing tests for detecting the presence of Ebola virus inside individual cells. The tests made infected cells glow red or green under a fluorescent microscope. You could see how Ebola virus was invading cells in the immune system and doing clever things that seemed to trigger a cytokine storm. She was getting closer to understanding how Ebola overwhelms the human immune system. This was important work, because there might never be a vaccine or cure for Ebola unless scientists understood how it killed.

Hensley found that she liked the peaceful feeling of working alone in a s.p.a.ce suit in Level 4, with n.o.body to distract her, nothing but the green cinder-block walls and her dishes of Ebola. She felt cozy inside the suit, even though the rooms around her were hot with the virus. It was like scuba diving. A s.p.a.ce suit was a sanctuary from the hubbub of the world. You could do your work without being interrupted by people asking questions or calling on the telephone, and you could press a little deeper into nature.

Hensley was growing Ebola in virus cultures. Viruses are grown in plastic well plates containing a liquid cell-culture medium. In the bottom of the wells there is a carpet of living human cells, alive and bathed in the liquid. (The cells are HeLa cells, cervical-cancer cells derived from an African-American woman named Henrietta Lacks, who died in Baltimore in 1951. Her cancer cells have become a cornerstone of medical research and have saved many human lives.) Hensley would infect plates of cells with Ebola, and in a few days virus particles would begin budding out of them. Ebola particles are shaped like spaghetti, and they grow out of the cells like hair. The strands break off and drift away in the liquid. The virus is amplified in the well plate, and in a few days the liquid becomes a virus soup, rich with particles of Ebola.

Hensley became good at making amplified Ebola soups. Using a pipette, she moved droplets of Ebola soup around from well to well, from vial to vial. She would hold the pipette in her heavy yellow rubber gloves, push a b.u.t.ton on the pipette with her thumb, pick up a small quant.i.ty of the Ebola soup, and then drop it into a vial.

Ebola soups are pale red, the color of a watered ruby, and sparkling clear. A well plate full of Ebola soup contains up to five million lethal doses of the virus-in theory, enough Ebola to make half of New York City crash and bleed out. Yet handling Ebola soup is no more dangerous than walking down a busy street. You could be killed if you stepped in front of a bus, but careful people watch where they are going. Hensley wore earplugs, and she heard nothing but the distant roar of cool, sterile air running in her s.p.a.ce suit. It sounded like surf on a beach.

Hensley spent so many hours working in her suit with Ebola that she began to get those dreams again. In her Ebola dreams, she would be moving droplets of Ebola soup from well to well, from vial to vial, working faster and faster, trying to complete an experiment, and there was never enough time to find out what she longed to know about viruses. In her dreams, she was always in control of Ebola virus, and Ebola never had control over her.

Panic in the Gray Zone JANUARY 12, 2000.

Hensley was working alone in her blue suit in hot suite AA4, near the center of the Inst.i.tute. It was about three o'clock in the afternoon. She had been working with soups of Ebola for many hours.

She wasn't feeling well: she had a cold and was a little achy, as if she might have a slight fever. She had probably caught a virus, but she was in the middle of an-experiment, and she couldn't abandon it just because she felt sick. She would lose her data if she went home.

She was holding a pair of blunt children's scissors with her rubber s.p.a.ce-suit gloves. (Sharp scissors are forbidden in Level 4.) She was trying to open a bottle by prying on a tab with the scissors.

Suddenly, they slipped, and the tip of the scissors jammed into the middle finger of her right glove. She felt a stab of pain near her fingernail.

She held her s.p.a.ce-suit glove in front of her faceplate. What had just happened? Had she cut the glove? The yellow rubber was wet, and as she turned the glove in the light, she couldn't tell if there was a cut in the rubber or not.

Inside her s.p.a.ce-suit gloves, she was wearing latex surgical gloves, for an extra layer of protection. Wriggling her arm, she pulled her hand out of the s.p.a.ce-suit sleeve and up inside her s.p.a.ce suit-the way Dr. Hatfill did when he ate a snack inside his suit-and inspected the latex glove at close range, inches from her eyes.

The rubber was translucent. Beneath it, she saw blood oozing out of her finger, moving along the fingernail. A red spot under the rubber was spreading along the cuticle. It hurt.

It is believed that a single particle of Ebola virus introduced into the bloodstream is fatal.

Hensley felt a sudden rise of fear, which turned into a little bit of panic. What was the last thing I touched with my hand? What was I doing? What were the scissors touching? Was there any soup on the scissors? The mind goes sticky in a moment of fear. She blanked. She couldn't remember what she had been doing with her hands. There was n.o.body to ask.

She began to talk to herself silently: Quit panicking and calm down. Did I make holes in both gloves? Or did I just crush my cuticle? She stuffed her arm back down into the sleeve of the s.p.a.ce suit and wiggled her fingers into the outer glove.

Time to get out of here.

She opened the decon-shower air-lock door, stepped into the air lock, closed the door, and latched it. She pulled the shower chain, and a spray of chemicals hissed down over her s.p.a.ce suit.

While she was taking the chemical shower, she realized that she did seem to have a lowgrade fever. Oh, this is great, she thought. I already don't feel well, and now they're going to take my temperature and then lock me up. She racked her brain trying to remember what she had been doing with her hand. Her glove had been slippery and wet ... wet with detergent. Some detergents kill Ebola particles. So if there had been Ebola on her glove, maybe the detergent neutralized it. The shower stopped, and she opened the exit door and went out into a Level 3 staging area and pulled off her s.p.a.ce suit.

The staging area is a gray room-in between the hot side and the cold side. It has lots of equipment in it, and along one wall there is a row of hooks that hold blue suits belonging to all the scientists who work in the suite. A laboratory technician, Joan Geisbert, was working in the gray area.

Geisbert is a slender, quiet woman with dark, wavy hair, dark eyes, and a serious, intelligent manner.

She is married to Tom Geisbert, Hensley's boss. Joan Geisbert is an expert in Level 4 laboratory work, with many years of experience. Hensley trusted her, but she thought she'd better not say anything.

This is no big deal, she told herself. She pulled off her surgical glove and washed her hands with disinfectant soap.

She needed to know if there was a hole in her inner latex glove. That was a serious question. If there was a hole in the glove and there was bleeding on her hand, then there was a chance the scissors had cut her skin. The tip of the scissors could have been contaminated with Ebola virus. Washing her hands would do no good if a particle or two of Ebola had made it into her bloodstream.

Joan Geisbert was puttering with something, not paying any attention to her.

The way to test a surgical glove for a hole is to hold it under a faucet and fill it with water, like a water balloon. If there's a hole, a thread of water will squirt out. Hensley went to a sink, filled her glove with water, and held it up to see. There was nothing, no leaks ... but when she squeezed the glove, drops of water oozed out of a hole in the finger.

Okay. She had cut her finger in the presence of Ebola Zaire. "Hey, Joan? I think I screwed up."

"Let me see." Joan Geisbert came over to the sink and inspected her finger and the hole in the glove while Hensley told her what had happened. Geisbert glanced at her with a look of alarm.

Oh my gosh, Hensley thought.

"Get dressed and report to Ward 200. I'll call Tom and have him meet you there."

Ward 200 contains a Level 4 biocontainment hospital suite known as the Slammer. Someone who has been exposed to a hot agent can live there for weeks in isolation, and if they become sick they are tended by nurses and doctors wearing s.p.a.ce suits.

Hensley took a water shower, got dressed in civilian clothes, and reported to Ward 200. By the time she arrived, Tom Geisbert was waiting for her. He was flushed and nervous. Peter Jahrling had been paged, and he had broken away from a meeting in Washington and was driving back to the Inst.i.tute as fast as he could. The ward started to swarm with medical doctors, Army officers, nurses, soldiers, and lab techs. An accident investigation team formed up and examined the cut on her finger. They wanted to know what she had been doing with her hands just before she had cut her glove. They took her temperature and discovered she had a fever. She explained that she thought it was just a cold. They stuck needles in her arm and drew out many tubes of blood. She was too nervous to sit on the exam table, so she leaned against it, and then she couldn't stop pacing around the room.

Tom Geisbert took an Army major named John Nerges aside. "Can you stay with her?" he said.

"Talk to her and keep her mind off it." John Nerges is a large, kindly man, and he was concerned about Hensley, but he joked around and kept up a patter with her.

Meanwhile, the investigation team took her latex glove into another room and studied the hole.

They measured the distance between the hole and the location of her cut. Maybe the scissors had not made the hole. They held a meeting out of her hearing. She paced up and down the hallway, with Major Nerges at her side. "Can I get you a soda or anything?" he asked.

"Yes, please."

She could see the Slammer every time she pa.s.sed the doorway. There was a bed with a bio-isolation tent around it, and a dummy lying on the bed. Teams of soldiers at USAMRIID used the dummy to practice handing a contagious patient. Major Nerges came back with a Diet Pepsi. "It's no big deal," he said. She popped the can and noticed that soldier had walked into the Slammer and had opened the bioisolation tent.

He picked up the dummy carried it away on his shoulder.

Hensley turned to Major Nerges. "If it's no big deal, why is he taking the dummy away?"

Major Nerges walked over to the grunt and swatted him lightly across the back of the head.

"You idiot, she's standing right there," he growled.

After interviewing her for two hours, and studying the glove and her hand, the accident investigators came to the conclusion that there was a low probability that Lisa Hensley had been infected with Ebola virus. Her glove had been wet with detergent, and they felt it would most likely have killed any virus particles. She was free to go home and get some rest. However, she would need to report to an Army doctor twice a day for the next three weeks.

She wasn't sure her mother should know about this. She went to a telephone near the Slammer and dialed her parents' house in Chapel Hill. Unfortunately, her mother answered.

"Hi, Mom. I need to talk with Dad about science."

In a moment, her father came to the phone, and Lisa told him what had happened.

He spent a long time calming her down. "Let's not tell your mother. I'll call you every day." He was worried about her, but he said, "I think you need to suck it up and get back in there and finish your experiment."

"I know. I know I do."

Otherwise, she might never go back.

At six o'clock, after most people had gone home, she returned to the locker room in suite AA4, put on surgical scrubs and her s.p.a.ce suit, and faced the steel door that led inward to Biosafety Level 4.

It was a matter of turning the handle and pulling the door open. That was not difficult. The staging room was quiet, empty, with only the sound of her breath running inside her faceplate, which was starting to fog up. Through her visor she saw the red, spiky biohazard symbol on the steel door. Suck it up and turn the handle.

Peter Jahrling arrived at the Inst.i.tute and went looking for Lisa Hensley. He didn't find her in her cubicle, so he went to Tom Geisbert's office: "Jesus, Tom, she'll never want to go back to the lab. Was she crying? Where is she?"

"She went into AA4, Pete."

"You're kidding."

The door was heavy, and it swung open slowly. She latched it behind her and stepped through the air lock to the hot side.

Up in Geisbert's office, Jahrling was saying, "Would you and Joan mind giving her the talk?"

"What talk, Pete?"

"The one I don't want to give her. About not sharing body fluids with anyone during the incubation period of Ebola."

An hour later, Hensley emerged from the hot suite, chilled and shivery, feeling a little feverish and perhaps a little trembly, but she had finished the experiment.

Joan and Tom Geisbert were waiting for her on the cold side. They invited her out to dinner at a Mexican restaurant, where they bought her some dinner and two beers. The beers helped. Tom and Joan looked at each other, and Tom said to Lisa, "I'm supposed to give you the talk about not sharing body fluids with anyone for a while."

"Yeah?"

"That was the talk."

"You mean when I kiss a guy, no swappin' spit?"

Tom turned red, and Joan burst out laughing.