On August 8, 2014, the World Health Organization declared the Ebola virus disease outbreak in West Africa to be a Public Health Emergency of International Concern (PHEIC). This seemed a truism to some attentive observers, and yet it was shocking to see the WHO make such a declaration in cold print. The announcement reflected the realities of a situation that, for a variety of reasons, had gone beyond the boundaries of previous experience with Ebola virus, so that even the experts were now on unfamiliar terrain.

Guinea had been the first country affected, then Liberia and Sierra Leone, and then by dire happenstance the virus travelled via airplane to Lagos, Nigeria, a raucous city of twenty-one million people. Elsewhere the numbers of cases and fatalities continued to rise quickly. Liberia was especially hard hit. Sierra Leone called out a battalion of soldiers to ensure that cases would remain isolated at treatment centers. In Guinea, amid rumors that health workers had deliberately spread the virus, riots broke out and young men with knives and guns threatened to attack a hospital. On the morning of September 2, Dr. Thomas R. Frieden, director of the CDC in Atlanta, told a CNN interviewer that the outbreak was “spiraling out of control.” This seemed as unnerving as the WHO’s PHEIC announcement; Frieden is no alarmist. Three days later, United Nations Secretary-General Ban Ki-moon issued an “international rescue call” for a “massive surge in assistance” from the global community, warning that the disease “is spreading far faster than the response.” By that time the total number of probable, confirmed, and suspected cases had reached 3,988, including 2,112 deaths—more cases, and more fatalities, than in all previously known outbreaks of Ebola combined. People around the world were worried and sympathetic and bewildered. People in Liberia and its neighboring countries were scared and angry and aggrieved. Many of them, too, were sick and dying.

Advertisement:

That’s where things stand as I write this, wondering which way the trends will have tipped by the time you read it. No one can predict just how much more awful the West Africa outbreak will become; there are too many variables, some of which are impossible to calculate, others calculable but (as Thomas Frieden suggested) almost beyond control. We don’t even know whether the past is a reliable guide to the future—that is, to what degree history and science can illuminate the Ebola events of 2014. But I’ve tried to offer a bit of both in this little book, science and history, on the chance that they might provide useful context for what you’re seeing, hearing, and reading in the news reports, and perhaps even make you slightly better equipped to act as global citizens in the face of what has become a global challenge. At very least, a bit of history and science can put in relief how present events might resemble, or differ from, those in the past, and why.

The outbreak seems to have begun as early as December 2013, in the Guéckédou prefecture of southern Guinea, not far from the borders of both Liberia and Sierra Leone. A two-year-old boy in a village called Meliandou began showing symptoms—fever, black stool, vomiting—and died four days later, on December 6. His mother hemorrhaged fatally the following week. Then his three-year-old sister sickened on Christmas, with symptoms similar to the boy’s, and died quickly too. Their grandmother, again after fever and vomiting and diarrhea, died on January 1, 2014. From there the outbreak spread, evidently by way of family care-givers, foot travel, and contacts that may have occurred at the grandmother’s funeral. It reached other villages, as well as hospitals in two nearby towns. A doctor in the town of Macenta, after attending one patient, took sick himself, with symptoms that included vomiting, bleeding, and hiccups, and soon died. The doctor’s funeral brought the virus to yet another town.

All this happened without being noticed by national or international health authorities. Then, on March 10, 2014, health officials from the region alerted the Guinean Ministry of Health about the alarming clusters of illness and death. Guinean doctors and scientists from the capital, Conakry, now became involved; Médecins sans Frontières (Doctors without Borders) also sent a team, which began caring for patients and sending blood samples up to BSL-4 laboratories in France and Germany for analysis. A team drawn from all these professionals hurriedly compiled a scientific report, with Sylvain Baize of the Pasteur Institute in Lyon as first author, which was published online by The New England Journal of Medicine in April, charting the chain of infections and making one other signal point. The bug they had found was not Taï Forest virus, as might have been expected on grounds of geography (given that Côte d’Ivoire shares a border with Guinea). No, this outbreak was caused by a different ebola virus, a variant of Ebola virus itself, as known from Gabon and the two Congo countries, roughly two thousand miles eastward. The Baize study also noted that the three kinds of fruit bat implicated by Eric Leroy’s group as suspected Ebola virus reservoirs, including the hammer-headed bat, are present in parts of West Africa.

Advertisement:

The hammer-headed bat, in fact, has a distribution that includes southern Guinea. Did the two-year-old boy in Meliandou, the apparent first case, contract his infection from a hammer-headed bat? It’s possible but it isn’t known.

Another important study of the genetics of the virus appeared in late August, in Science Express (a streamlined publication of the journal Science), under the authorship of Stephen K. Gire, of Harvard, and a long list of coauthors. Five of those coauthors, having worked amid the outbreak, had died of Ebola virus disease by the time this study was published, giving it a certain extra gravitas. Based on their sequencing of the genomes of virus samples from 78 patients in Sierra Leone, Gire and his colleagues reported three notable results. First, the virus was mutating prolifically and accumulating a fair degree of genetic variation as it replicated within each human case and passed from one human to another. (So it was changing, evolving, as time progressed; whether it was adapting to humans is a separate but related question.) Second, the 78 samples were sufficiently similar to suggest that they had all descended from a single recent ancestor, implying just one spillover from the reservoir host. Third, comparative analysis of the samples showed this West African variant of Ebola virus to be distinct from Ebola virus as lately seen in the Democratic Republic of the Congo by about ten years worth of mutational differences. It had evidently evolved independently in its reservoir host for about a decade since becoming isolated from the Central African lineage.

That last finding, just ten years worth of localized mutation for the virus within its West African reservoir, seemed to suggest that Peter Walsh might be right. Is it possible that Ebola virus is still spreading like a wave through the bat populations of Central and West Africa—reaching new locations, diverging genetically, and presenting new dangers to people in those places? Maybe.

Advertisement:

While these scientific studies progressed, so did the spread of the outbreak and the anguished but unsuccessful efforts to contain it. Those efforts were hampered by a number of factors: the weakness of governance in Liberia, Guinea, and Sierra Leone after decades of coups, juntas, and civil wars; the bitterness and suspicion among their peoples as legacy of those conflicts; the inadequacy of health-care infrastructure and basic health-care services in the three countries, as reflected in extremely low annual per capita expenditures on health; the immediate shortage of money and outbreak-response supplies necessary for stopping Ebola, such as examination gloves, masks, gowns, rubber boots, bleach, and plastic buckets in which to put bleach solution so that hands could be washed; the shortage of treatment centers and beds within them; the porosity of the national borders between Guinea, Liberia, and Sierra Leone; the reluctance of people in affected villages and towns to see their loved ones confined to isolation facilities, within which treatment was often marginal and case fatality rate was running above 50 percent; the reluctance of people to suspend their traditional burial practices, which often involved washing or otherwise touching the body; the relatively short distances between rural areas where the outbreak started and the capital cities of the three countries, allowing people to travel from affected areas to Monrovia, Freetown, and Conakry by such relatively inexpensive modes of transport as shared taxi and bus; and the shortage of timely international aid. Notwithstanding heroic efforts by many Liberian, Guinean, and Sierra Leonean doctors, nurses, and other health-care workers, and by the courageous foreign responders from Médecins sans Frontières, Samaritan’s Purse, the CDC, the WHO, and other organizations, there just wasn’t enough material support and expertise on the scene, not yet, to contain this unusually difficult outbreak.

And then the virus rode an airplane to Nigeria. Some observers, including myself, had noted in the past that Ebola virus doesn’t ride airplanes well, because it tends to debilitate its victims so quickly, and because it typically affects poor people in remote villages amid forest areas, who can’t afford air travel anyway; but we were wrong if we seemed to imply that it can’t ride airplanes at all. On July 20, a Liberian-American man named Patrick Sawyer arrived in Lagos after a visit to Liberia, during which he had reportedly cared for his Ebola-stricken sister. He sickened during the last leg of the flight and was admitted to a hospital in Lagos, where he died on July 25. “Within days of his case being diagnosed, authorities in Nigeria were following 59 people who had had contact with the man,” according to an account by Helen Branswell, a medical reporter for the Canadian Press, Canada’s news agency. “The case count started to grow. A doctor tested positive. Then a nurse, who died.” Although public health workers in Lagos traced Sawyer’s contacts assiduously, one of them escaped the net and, defying a quarantine order, flew south to Port Harcourt, an oil-refining city of almost two million people on Nigeria’s southern coast. There the escapee infected a doctor, who infected others, igniting a worrisome new hotspot of the outbreak.

Advertisement:

The virus has now also reached Senegal, another West African neighbor, by way of a student from Guinea. It may well get to other locations, other countries, transported within infected people by bus, foot, or bicycle across open borders, or by air travel internationally or intercontinentally. So we have reached a point, as of September 2014, where we’ve got to stop calling this an outbreak and begin calling it an epidemic. Stephen K. Gire and his colleagues took that step in their genomic study of the virus.

The word “pandemic,” so fearfully resonant, is still inappropriate and—with anything but the worst of luck—will continue to be inappropriate. Ebola as we know it is just not the right sort of virus to spread around the world, as influenza regularly does, and as another respiratory bug such as SARS coronavirus might, causing tens of thousands of deaths, not just in poor countries but also in wealthy ones with all the advantages of strong governance and rigorous health care. This is still a slow-moving virus, compared to many. What we should recognize, what we should remember, is that the events in West Africa (so far) tell us not just about the ugly facts of Ebola’s transmissibility and lethality; they tell us also about the ugly facts of poverty, inadequate health care, political dysfunction, and desperation in three West African countries, and of neglectful disregard of those circumstances over time by the international community.

That said, though, I’ve got to mention one other dangerous factor we need to consider: evolution. As I mentioned above, the Gire study found a “rapid accumulation” of genetic variation in the virus from those 78 patients. The observed rate, in fact, was twice as high as the normal rate of mutation in Ebola virus between outbreaks. Furthermore, some or many of those mutations have been consequential ones (“nonsynonymous,” in genetic lingo), changing the identity of an amino acid for which the RNA codes. Change like that can lead to functional changes. The high rate of nonsynonymous mutations, according to Gire and his colleagues, “suggests that continued progression of this epidemic could afford an opportunity for viral adaptation, underscoring the need for rapid containment.” In plain language: the higher the case count goes, the greater the likelihood that Ebola virus as we know it might evolve into something better adapted to pass from human to human, something that presently exists only in our nightmares.

Advertisement:

The other piece of grim but illuminating news, as I write this, is that another outbreak of Ebola virus disease has begun, far to the east, in a remote and forested northern province of the Democratic Republic of the Congo. The Congo outbreak involves a different variant of Ebola virus from the one at large in West Africa, and therefore it must have resulted from an independent spillover. The death toll had risen to 32 by September 6, when the DRC Minister of Health told a press conference that the outbreak can be contained. Probably it can. The city of Kinshasa and its N’Djili International Airport are five hundred miles away, and that’s a long bus ride for a mortally ill person.

What will happen next? Nobody knows. That’s the best wisdom of science and public health and all other expert prognostication at this point: Nobody knows the future. It’s contingent on the scope and the speed of coordinated response, and on luck. What we do know is that the problem of Ebola virus is both acute and chronic. Acute: The West African epidemic of 2014 must be contained, and ended, and to do that will require radically more international commitment—in money and material and logistical help and expertise and courageous health workers volunteering to serve in the most difficult conditions—than has been offered so far. Chronic: When that epidemic has been stopped, and the Congolese outbreak too, Ebola virus will not be gone. It will only be hiding again. It will recede into its reservoir host, somewhere amid the forest, and await its next opportunity. We live on a complicated planet, rich with organisms of vast diversity, including viruses, all interacting opportunistically, and although there are seven billion of us humans, the place has not been arranged for our convenience and pleasure.

Excerpted from "Ebola: The Natural and Human History of a Deadly Virus" by David Quammen. Published by W.W. Norton and Co. Copyright 2014 by David Quammen. Reprinted with permission of the publisher. All rights reserved.