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The Coming Plague

Page 30

by Laurie Garrett


  The Legionella bacterium, as it was dubbed, had peculiar dietary needs. Standard laboratory culture media wouldn’t support growth of the persnickety microbe: it needed supplements of the amino acid cysteine, vitamins, and minerals, particularly iron. Accustomed to living in what is politely referred to as pond scum, Legionella preferred dark, nutrient-rich, almost anoxic environments. It also enjoyed living inside the cytoplasms of larger one-celled organisms.56

  These conditions rendered the organism impossible to see through microscopes with standard techniques. When treated with silver, however, the organism clearly revealed itself, and Shepherd and McDade saw the long, round rods of Legionella squirming on their slides.

  The epidemiology team in Philadelphia meanwhile noticed that most of the Legionnaires’ Disease sufferers had spent time schmoozing in the five cocktail suites run by the candidates for leadership of the veterans’ group. Further analysis revealed that the bacteria thrived in the Bellevue-Stratford Hotel’s cooling tower. From that water supply, the hotel derived its air conditioning. The Legionella organisms were hidden in biofilm “scums” along the edges of the cooling tower, and were actively pumped into the hotel’s hospitality suites during the hot month of July.

  It wasn’t long before similar cases of Legionnaires’ Disease surfaced all over the world. First, the CDC spotted isolated cases in eleven different states.57 By September 1977, the federal agency was busily tracking three hospital outbreaks in Ohio,58 one in Vermont,59 and one in Tennessee.60 The combined fatalities in the Ohio, Vermont, and Tennessee outbreaks and sporadic isolated cases in 1977 reached thirty-two by December, about 25 percent of all reported Legionnaires’ cases.61

  In the fall of 1977 a small epidemic of Legionnaires’ broke out in a hospital in Nottingham, England, leaving three patients dead.62

  In the summer of 1977 Legionnaires’ struck a brand-new hospital located in one of the wealthiest parts of Los Angeles. The Wadsworth Medical Center, a veterans hospital, situated between the posh communities of Bel Air and Brentwood, was the site of a yearlong outbreak of the disease that infected about 3 percent of all patients who passed through the facility, caused disease in both staff and patients, and claimed sixteen lives.63

  By late 1978 scientists had discovered the Legionella bacterium in soil samples, ponds, cooling towers, water-driven condensers, slow-flowing creeks, mud, polluted and silty water, at construction sites, and in steam turbines. In coming years, they would find the dangerous organism in shower heads, grocery store vegetable counter misters, hot tubs, fountains, and a wide variety of humidifiers and other devices that aerosolized water.

  Clinically, it was soon apparent that the organism was most dangerous to cigarette smokers, people recovering from surgery, and individuals who were suffering some type of immunosuppression. It seemed the bacteria were inhaled from the environment; never were they transmitted from person to person. Once somebody was infected, the Legionella were tough to defeat because they were resistant to a wide spectrum of antibiotics.

  Air-conditioning standards changed after 1976, with federal agencies all over the world requiring far more stringent cleaning and hygiene provisions for cooling towers and large-scale air-conditioning systems.

  In the case of Legionella, a new human disease had emerged in 1976, brought from ancient obscurity by the modern invention of air conditioning.

  At the CDC’s International Legionnaires’ Disease meeting in 1978, several particularly ominous facets of the bug were scrutinized. CDC scientists revealed that the organism could be found in tap water, shower nozzles, and other allegedly clean water sources. One tap water study showed Legionella could survive over a year inside pipe biofilms, emerging in wholly infectious form once the faucet was turned on full force. It thrived in temperatures from ice cold to steamy hot. Even distilled water samples occasionally contained small numbers of Legionella organisms.

  A team of scientists from the Denver Veterans Administration Medical Center was particularly prescient, predicting the bacteria might survive chlorine purification efforts. “The residual amount of chlorine recommended (0.2 ppm) for standard water purification may not be sufficient for killing the LD bacterium when it is present in high concentrations,” the group wrote.64

  Bacteriologist Mortimer Stall, of the University of California, Davis, warned that the soils and waters of the earth were replete with organisms not yet identified, many of which might, like Legionella, one day be provided the proper circumstances for their emergence as human pathogens. Plant bacteria such as Serratia and Pseudomonas were known to cause human disease, he noted, and it would be arrogant for humanity to assume it had identified all of its flora, marine, and soil microbial enemies.

  “The existence of plant-animal ambilateral harmfulness is generally unrecognized, even though I have assembled more than 200 bacteriological and mycological examples, mainly in the ‘questionable’ category,” Stall told the international gathering. “It seems, then, that ambilateral harmfulness may have a significant bearing on the ‘emergence’ of ‘new’ infectious diseases … because the ability of a plant microbe to harm an animal (or vice versa) in any manner whatsoever would seem to indicate that the ‘emergence’ of a ‘new’ pathogen is not far off!”

  The CDC estimated that somewhere between 2,000 and 6,000 people had been dying every year of Legionnaires’ Disease, probably for decades, certainly since the advent of air-conditioning technology and, long before that, indoor plumbing. Prior to the dramatic Philadelphia outbreak, these cases had simply been dumped into the category of “pneumonia of unknown etiology.”

  Armed with such observations, medical historian Robert Hudson of the University of Kansas closed the international gathering on a particularly frightening note. After describing the Black Death plague of medieval Europe, Hudson warned that “when we grant that our knowledge of existing microscopic pathogens is deficient, we necessarily grant the possibility at least of a return of the great epidemics of the past … . the possibility exists that a deadly and common organism could emerge that is easily spread from person to person and that might be aloof to all available therapeutic and preventive methods.”

  “The Philadelphia event remains unsettling because it shows the very real limitations of our tools for investigating an apparently new microbial disease,” Hudson concluded. “If we are to retain public confidence in the face of some future serious epidemic, it is important that our limitations be widely understood. As a medical community, there is no cause to feel humiliated by the Legionnaires’ affair, but it is altogether proper that we be humbled.”65

  Chagrined by events of 1976, the U.S. public health community looked to the future, for the first time in the late twentieth century, with a vague sense of unease.

  7

  N’zara

  LASSA, EBOLA, AND THE

  DEVELOPING WORLD’S ECONOMIC

  AND SOCIAL POLICIES

  Improvement in health is likely to come, in the future as in the past, from modification of the conditions which lead to disease, rather than from intervention into the mechanisms of disease after it has occurred.

  —Thomas McKeown, 1976

  The microbe is nothing; the terrain everything.

  —Louis Pasteur

  While his colleagues in Atlanta anguished over Swine Flu damage control, Joe McCormick was content to finally have a chance to uncrate several thousand pounds of laboratory equipment and build his remote Lassa Fever Research Unit in Sierra Leone. It hadn’t been easy getting all the gear by ship from Atlanta to Freetown and by assorted trucks along the sporadically paved roads to Segbwema.

  But here he was, at long last, on his own, in charge, doing what he most loved: science. Months earlier, long before he was detoured off to the Sudan to chase down the Ebola virus, McCormick sat
down with Karl Johnson and mapped out a strategy for his Lassa research.

  There was so much to do.

  He wanted to find out just how widespread Lassa virus infection was in the West African Mastomys rat population. McCormick planned to do antibody tests on thousands of Sierra Leonians to see how many had ever been infected with the virus.

  “While I’m at it, might as well check for antibodies to Marburg and Ebola. Wouldn’t it be a kick if it turned out those things were up there,” McCormick told Johnson just before he left Zaire.

  Pat Webb would later join Joe, and that pleased him. She was one of the best field lab workers he’d ever seen, and McCormick knew he could count on Webb’s data: it would always be reliable. He appreciated her caustic, opinionated way of looking at the world, always coupled with a great sense of humanity. She could be counted on for ample hilarity.

  Not long after getting settled in and starting up laboratory operations, McCormick received a cable from the U.S. Embassy in Freetown summoning him for a top secret meeting. After traversing the backbreaking roads from Segbwema to Freetown, McCormick was informed that his presence was required immediately at the U.S. Embassy in nearby Monrovia, Liberia. It was an official diplomatic summons, passed from the Liberian government of President William R. Tolbert, Jr., to the Carter administration in Washington. The U.S. State Department cabled word to its embassy in Freetown that Liberia had requested McCormick, by name. And he had better go.

  When McCormick finally reached the U.S. Embassy in Monrovia, he was informed that the Tolbert government, which was aligned with that of the United States in Africa’s crazy-quilt mixture of Cold War allegiances, was concerned about the recent arrival in the country of four Soviet scientists. The Soviets, who were interested in Lassa research, had arrived in Monrovia a few days earlier, unannounced, requesting unusual and basically unobtainable supplies, such as tanks of liquid nitrogen and various compressed gases.

  The U.S. Embassy set up a formal meeting, attended by McCormick, the four Soviets, and representatives of the U.S. and Liberian governments. One of the Soviets was a bona fide scientist: Sasha Kachenko had collaborated years earlier with Karl Johnson on studies of hemorrhagic fevers in Russia and the Ukraine. The true identity of the other three was less clear, though Joe was certain at least one was a KGB agent. The fellow certainly didn’t know anything about basic biology. It was obvious after twenty minutes of vague conversation that the Soviets had no lucid plan for studying the Lassa virus.

  “Hell,” McCormick told embassy officials, “it sounds like they’re just going to wander around collecting rodents.”

  Once outside the embassy, far from electronic surveillance, the Soviet team pressed McCormick for assistance. They wanted Lassa antibodies, reagents, and, most important, samples of the virus. They also wanted to know how to do Lassa research.

  Convinced it would be dangerous to turn over samples of such a lethal virus to men he was certain worked directly or circuitously for Soviet intelligence, McCormick simply smiled and told his luncheon companions that all such requests would have to be submitted in writing to the director of the CDC in Atlanta.

  Throughout 1977 and 1978 the Soviet researchers continued importuning McCormick and the CDC for Lassa virus samples. And the CIA grilled McCormick after every contact with the Russians. McCormick and then former CDC director David Sencer were convinced that both sides in the Cold War feared the other was developing Lassa as an instrument of biological warfare. As a weapon, Lassa certainly had many desirable characteristics: better than 90 percent lethality in nonimmune populations, extraordinary virulence that needed only minute doses for infection, apparent viral tolerance of a variety of hostile environments, and, most important, no clear treatment or antidote. Furthermore, because of the circumstances surrounding Mandrella’s infection, military researchers on both sides of the Iron Curtain were convinced that lethal infection could result from inhalation of the virus.1

  The Soviets had first approached the U.S. government five years earlier, requesting a sample of the Lassa virus during a Moscow visit by U.S. Secretary of State Henry Kissinger. Because he had publicly vowed complete openness in United States/U.S.S.R. information exchange as part of ongoing nuclear and biological arms negotiations between the Nixon and Brezhnev administrations, Kissinger ordered the CDC in 1972 to accede to the Soviet request.2 Sencer later did so by personally hand-carrying a vial of the virus to Moscow.

  It was, therefore, unclear to the CDC in 1977–78 why the Soviet researchers in Liberia needed further samples of the virus, and though the superpowers had signed a treaty forbidding biological weapons use and development, the U.S. agency remained suspicious of Soviet intentions.

  Though the Soviet effort in Africa over the coming years was far larger than anything McCormick and Webb could muster in Sierra Leone on their meager CDC funds, it accomplished nothing. Four separate teams of Soviets “were wandering around in a thick fog, with no sense of direction,” McCormick told Webb. Both the CDC scientists felt that a golden opportunity to do stellar collaborative work was lost. The Americans couldn’t conduct research in Guinea because the United States did not have diplomatic relations with President Sékou Touré’s left-wing government. Similarly, the Soviets couldn’t freely roam about the countryside in search of Lassa in Senegal, Liberia, Sierra Leone, or Nigeria.

  For years separate and often isolated research was conducted, and both superpowers would eventually shut down their West African Lassa laboratories, leaving the Africans the ultimate losers. At McCormick’s insistence the CDC would maintain a collaborative Lassa research effort with Sierra Leone and occasionally Nigeria well into the 1990s. But the Soviet operations would be abandoned in 1984 following a Guinean coup d’état, leaving behind no obvious scientific legacy.3

  As time went on in the late 1970s, McCormick wasn’t even sure his efforts in Sierra Leone constituted a lasting legacy for the people of that nation. Though he, Webb, and other CDC colleagues amassed an impressive store of information, they had tremendous difficulty in translating the newfound knowledge into meaningful action. The virus was carried by the Mastomys rats, which were ubiquitous throughout the villages, swamps, and forests of West Africa. The rats lived inside huts and homes, people tolerated—even ate—the rodents, and the rats urinated on stored grains and the dusty dirt floors. Once people became ill, they went to hospitals that failed to follow hygienic practices aimed at preventing spread of the virus from patient to patient.

  McCormick drew blood samples from hospitalized patients in Sierra Leone’s eastern province, discovering that on any given day some 5 to 15 percent of the adult patients were infected with the deadly virus. McCormick and his CDC colleagues surveyed the remote villages of the country’s northern savanna area, finding that up to 40 percent of the adult residents of some locales had antibodies against Lassa, which proved that they had been previously exposed to the virus. Nationwide, nearly 9 percent of Sierra Leone’s citizens tested positive for antibodies against the virus.4

  Together with Guido van der Gröen, then with the Institute of Tropical Medicine in Antwerp, McCormick collected all available blood studies and data on Lassa from all over Africa for the World Health Organization. In 1977 a second type of Lassa virus was discovered in Mastomys rats in Mozambique, and eventually one or the other Lassa strain was found in the blood of those rodent species in every country in which they were able to look, from Mozambique and Zimbabwe in the southeastern corner of Africa all the way up to Senegal and Mali in the northwest.

  McCormick and van der Gröen told WHO that the scope of rodent and human infection in Africa clearly showed that what had seemed an extraordinarily rare and mysterious disease in 1969 when Penny Pinneo took ill was actually a highly endemic problem in scattered villages across the continent.5

  When an infectious vector-borne disease was tha
t thoroughly entrenched, and its carrier—the rat—that perfectly adapted to cohabitation with human beings, classic public health training dictated just three options for limiting the further spread of the disease: a vaccine, a cure, or elimination of the vector.

  But there was no Lassa vaccine, nor did one appear likely in view of the lack of interest in developing one at the laboratories and pharmaceutical companies of the wealthy nations. McCormick’s initial hopes that stockpiling plasma from people who had recovered from Lassa would result in a storehouse of curative antiserum were quickly dashed. He soon discovered that few people made sufficient antibodies to be useful in preventing full-blown disease in other infected individuals. Indeed, he found most people didn’t even muster a strong enough immune response to prevent their own reinfection, and repeated episodes of Lassa fever were fairly common.

  In the villages of Sierra Leone, fevers were a constant presence and had been for millennia. The people assumed most fevers were caused by mosquito-borne diseases—malaria and yellow fever—or by sorcery and evil spirits. McCormick discovered that about one out of every ten cases of high fever in the villages was caused by the Lassa virus.

  Most of the time—perhaps over 98 percent of the time—people recovered from Lassa fever, but their illnesses lasted many days, even weeks. During that time they were unable to work, and McCormick could see the enormous economic toll Lassa took on the villages. In contrast, if people got infected in a hospital, through blood-to-blood contamination of medical equipment, their chances of getting sick and dying were far greater: 16 percent of such infections were fatal.

  McCormick and Webb experimentally treated Lassa with a new injectable drug called ribavirin. The antiviral drug had already proven effective in treating some other viral infections by blocking the ability of the viruses to reproduce. It worked on Lassa, McCormick and Webb found, provided it was administered before full-blown symptoms developed.

 

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