Forty days later, on Christmas Day, the woman developed symptoms of acute viremia and was put in a general ward of Evangel Hospital. Throughout her hospitalization the woman's newborn and three-and-a-half-year-old child stayed beside her, and she was closely tended to by her mother and brother-in-law.
By mid-January the woman was well enough to return to Bassa, but shortly after the family reached their home the older child died and the woman's mother fell ill.
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Altogether, twenty-eight people suffered Lassa fever in the two hospitals between Christmas 1969 and February 26; thirteen died. With the exception of Jeannette Troup, all were Nigerian.
At least sixteen people got Lassa from the first Bassa woman, though most never had physical contact with the patient. Much to the embarrassment of Evangel physicians, it seemed most infections actually occurred on the A Ward of their hospital. There, the Bassa woman struggled with her fever for two weeks, lying on a corner bed beside an open window. The prevailing breezes carried her exhaled viruses down the ward, past the noses and mouths of four patients, six visitors to the ward, and four hospital employees, all of whom developed Lassa. The infected, in turn, passed the virus on to family members after leaving the hospital, indicating it was possible for Lassa survivors to carry the virus for two or more weeks.
Searches throughout Bassa failed to find the source of the epidemic.
For Frame, who was responsible for the health and safety of SIM missionaries in West Africa, the second Lassa outbreak was particularly worrisome for three reasons: it occurred primarily among Nigerians, indicating there might not be natural immunity in the population; the outbreak clearly spread as a result of hospital procedures; and the source of the disease remained elusive.
In 1970 Frame collected blood samples from 712 current and recent
American missionaries working in West Africa and had them tested for evidence of past Lassa virus infection.
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Five tested positive, four of whom recalled having suffered long, unexplained fevers. Only one member of the group, Harry Elyea, had been ill while in Nigeria. In 1952, Elyea spent a month in Rahama, Nigeria, severely ill. As a result, he suffered a lifelong hearing deficit.
20
Hearing loss would prove a common side effect of Lassa infection. Twenty-five years after her brush with death from Lassa fever, Pinneo would still have a constant ringing in her ears.
The other four cases were missionaries who fell ill between August 1965 and February 1968 in far-off Telehoro, Guinea. Sixty-one-year-old missionary Carrie Moore was rendered stone-deaf by her illness, having suffered total auditory nerve destruction.
Frame's group also tested blood samples that had been collected in 1965â66 from villagers in northern Nigeria as part of a parasite survey; 2 percent showed signs of previous Lassa infection. The scientists suspected Lassa was hiding inside some ubiquitous species of African animal and might well be infecting human beings all over West Africa. With so many fever-producing diseases to worry about in the tropics, it was to be expected that the occasional Lassa case would go unnoticed.
They warned that Lassa would undoubtedly strike again.
It was just months before their prediction proved sadly accurate. Not in Nigeria, nor Guinea, but Liberia.
Garbazu, a Liberian peasant, was four months pregnant when she started bleeding profusely. Though she had been nauseated and sick for a week, she tried to treat herself in her village of Zigida, using traditional antisorcery methods of herbs and incantations. The uterine bleeding, however, scared her enough to prompt a twenty-seven-mile journey to the Curran Lutheran mission hospital in Zorzor.
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On March 3, 1972, Esther Bacon, a missionary nurse-midwife from Colorado, performed an emergency dilation and curettage after Garbazu spontaneously aborted twins. Throughout the procedure, Garbazu bled an inordinate amount, hemorrhaging so severely that Bacon's nursing gown soaked through, as did her cotton dress beneath, leaving her torso drenched in Garbazu's blood.
After a few days, Garbazu recovered and went home to Zigida, but two other women with whom she had shared the ob-gyn ward developed similar symptoms: nausea, mouth sores, fevers. By mid-March, Bacon was ailing, as were other members of the hospital staff. At month's end, five patients (including an ob-gyn patient's newborn baby) and eight hospital staff members were sick,
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and, as rumors spread of Lassa fever, panic erupted in Zorzor. Travelers zoomed through the town, their car windows shut tight against imagined plague. And residents of neighboring towns became dangerously agitated.
The fear was compounded by a very special concern for Bacon. Since her arrival in Zorzor in 1941, the energetic midwife had personally revolutionized
health care in the region, and eventually throughout Liberia, by creating a vast infrastructure of trained midwife assistants and prenatal screenings. Twice she was awarded Liberian presidential medals for her years of walking hundreds of miles to far-flung villages to convince women of the wisdom of delivering their babies in clean hygienic settings, assisted by trained personnel.
Located in the high-country tropical forestland of eastern Liberia, close to the Guinea border, Zorzor was a remote area where sorcerers usually resented the intrusion of all forms of competing providers of medicine, yet Bacon managed to gain respect even in villages located so deep in the rain forest that they could only be reached by horseback or on foot.
When word spread of Bacon's illness, prayer meetings occurred spontaneously throughout the region and the fear of Lassa fever grew. People wondered, “What can be so terrible that it can kill nurse Bacon?”
On Good Friday, March 30, Bacon was carried from her home to a small landing strip, where she would board a prop plane bound for the somewhat more sophisticated Phebe Hospital. As her stretcher-bearers wended their way to the airstrip, the people of Zorzor lined the path, some crying out, others sobbing.
Samples of blood drawn from Bacon and other ailing hospital staff members
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were forwarded to the CDC in Atlanta, and health officials in Liberia, as well as WHO headquarters in Geneva, were alerted. Once again, Penny Pinneo, who had remained in Jos, was asked to donate her services and her blood. Now convinced that God had intended her to survive Lassa for just such a purpose, Pinneo enthusiastically complied.
Though Pinneo brought two units of antibody-containing plasma, the blood proved useless for Bacon. As Karl Johnson had predicted three years before, antisera was effective for viral hemorrhagic diseases only when given early in the illness.
On April 4, Esther Bacon died.
When Esther Bacon fell ill, Tom Monath was just finishing up his research fellowship in virology at the University of Ibadan in Nigeria. The thirty-year-old Bostonian had developed a fascination with insect-carried viral diseases during his medical studies at Harvard, and went to Nigeria to study yellow fever. By March 1972, his work was done, crates were packed, and Monath was already imagining sinking his teeth into a nice juicy all-American cheeseburger when a cable arrived from the CDC.
“Go to Liberia,” it read, noting there were reasons to suspect Lassa fever had broken out in a tiny mission hospital. He was instructed to link up with Penny Pinneo and get to Zorzor as fast as possible. His job was to find out where Lassa came from and how it was spread.
For a moment Monath just stared at the cable, struck by a flash of fear. “This is pretty terrifying,” he thought. “Nobody really knows anything about this. It's highly contagious, and half of the people who got it in Jos died.”
But hours later, as he unpacked gear he had already prepared for shipping
to the United States, Monath deliberately downplayed the assignment, telling his wife it was “no big deal, probably routine.”
Pinneo and Monath made their way from Lagos to the Liberian capital of Monrovia, and then took a tiny light-wing plane to Zorzor. The moment they landed the pair could feel the pall over the community. Nobody was walking along the roads, and travelers refused to make their usual stopovers for gasoline and food in Zorzor.
“The air smells like fear,” Monath thought.
Bacon was still aliveâbarely. Several hospital beds were occupied by other Lassa patients, and the staff was frankly stupefied by it all. Pinneo and Monath met with the hospital director, Dr. Paul Mertens, and Tom laid out a battle plan.
“First, we go to Zigida, track down Garbazu, and try to figure out where she got the virus,” Monath said. While Pinneo and Monath searched the village, Mertens would try to determine how the virus spread within his hospital. Because she was immune, Pinneo agreed to be in charge of drawing and handling blood samples.
Before he left Zorzor, Monath grabbed every mousetrap and net he could find. Though all his training was in insects, Monath knew that Junin and Machupo were rodent-carried diseases, and circumstances just didn't point to insects in either Jos or Zorzor; if insects had carried the disease the cases would not have all occurred indoors or been primarily among adults. As a rule, insect-carried diseases attacked children more than adults because youngsters tended to play outdoors in watery or wooded areas where they came in contact with mosquitoes, mites, spiders, and such.
But in Zorzor only one child had Lassaâa newborn who undoubtedly got infected as a result of blood-to-blood contact with its dying Lassa-infected mother.
As they headed for Zigida, Monath reviewed what he had heard about rodent disease carriers and tried to imagine what a real CDC rodent expert might do in the situation.
Neither Pinneo nor Monath spoke the Liberian languages of Loma or Kpelle, but the government conducted its affairs in English because the nation was founded by freed American slaves in the nineteenth century, and even in remote villages it was possible to get by with basic English. They found Garbazu and gained village approval to take blood samples from her friends and relatives, set mousetraps, and collect local animals. While Pinneo patiently drew blood from anxious villagers unaccustomed to such procedures, Monath hunted.
Night after night Monath crouched by candlelight, a net grasped tightly in one well-gloved hand, the other constantly adjusting his respirator. In this manner he captured dozens of bats, always aware that the fangs of the animals that were thrashing about in his nets might carry the deadly virus. With only a flickering candle to illuminate his actions, Monath carefully
placed each captured bat in a thermos full of liquid nitrogen, freezing their bodies for future study at CDC high-security laboratories in Atlanta.
Monath failed to find the animal culprit responsible for the original Zigida cases, but blood tests of 133 villagers showed that, in addition to Garbazu, four people had survived bouts of Lassa fever.
Back at the hospital, Mertens and Monath were joined by Jordi Casals, who was sent by the CDC. Together they scoured the building for pests, but eventually were forced to conclude that the mini-epidemic constituted a classic case of nosocomial transmission: spread of disease between patients and medical staff.
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Nurse Esther Bacon, they decided, clearly became infected during the dilation and curettage performed on Garbazu, who presumably somehow contracted Lassa fever in Zigida.
Garbazu was on the Curran Lutheran Hospital ob-gyn ward from March 1 to 19. During that time Nessie, who was recuperating from a kidney infection during pregnancy, lay in the bed that was beside Garbazu's for a few days, sharing her newfound friend's food and water. Nessie recovered nicely from her pyelonephritis and was discharged. Five days later she returned, suffering a soaring fever. Nessie died of Lassa.
Liberian midwives Jetty Ziegler and Phebe Hollwanger, having tended to both Nessie and Garbazu, fell ill in mid-March, but recovered fully from Lassa after a few weeks' time.
Sarah wasn't so lucky. Bedded just twenty feet downwind from Garbazu, the Kpaiyean villager was recuperating from an emergency caesarean section and caring for her newborn baby. The very day Garbazu left Curran Lutheran Hospital, Sarah developed a sudden searing headache, her fever spiked at 103°F, and she was unable to sit up. On April 4 her birth canal began hemorrhaging so severely that Sarah went into shock and died. Four days later her baby succumbed.
In all, eleven women got Lassa in Zorzor in 1970, all of whom had been in the Lutheran hospital; seven were members of the staff. Four people died: Esther Bacon, a Liberian obstetrics patient named Sarah, her newborn baby, and Juanita Akoi, a Liberian nursing assistant.
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Two of the survivors were rendered hearing-impaired, one was completely deaf.
The team tested fifty-nine other patients who had been in the hospital during Marchâsix tested positive for Lassa. Among the fifty-seven hospital staff members, in addition to the seven known to have had the disease, two more tested positive. Both had worked on the obstetric ward tending to Sarah, Garbazu, and Nessie.
Nessie's case particularly troubled the researchers because it implied Lassa could have a long latency time (nineteen days), and could even recur. The prospect of Lassa relapses among his staff was particularly unnerving for Mertens.