The subtitle for Richard Preston’s 1994 bestseller reads: “The Terrifying True Story of the Origins of the Ebola Virus.” How much you enjoy The Hot Zone might just hinge on what you know about Ebola going in and, by extension, how seriously you take that subtitle. To say that Preston took artistic liberties is akin to saying Ayn Rand held only a little contempt for Marxism or that Memento had a tendency to confuse its viewers. There can be no doubt that Preston delivered a vivid and hair-raising thrill ride, a marvelously written if unevenly paced house of horrors, but on balance his book is about as accurate as a Stone age slide rule. It might have passed for harmless over-sensationalizing, except with the Ebola epidemic in-progress and tensions wound tighter than ever, the book has become the bane of disease experts and science communicators working to tamp down the mass hysteria. In this case, thankfully, the truth isn’t scarier than fiction.
The book is structured around four events: our first contact in the 1960s with Marburg virus (MARV)—a close cousin to Ebola—named for the German city in which it was discovered; the earliest recorded outbreak of Ebola Zaire (EBOZ) in Sudan and DRC (formerly Zaire) in 1976; the 1989 outbreak of Reston virus (RESTV) in Northern Virginia; and the final act sees Preston donning a biocontainment suit for a solo jaunt in a sub-Saharan cave in search of the cagey killer.
Preston needs only the space of a few pages to subdue the reader into a state of trepidation. I was spooked almost immediately, even knowing it was all a bit light on fact. The characters, many of whom are given fictitious names, have blood spurting from every orifice, their insides “liquefying”, and at one point we read of a nurse “weeping tears of blood”. Such descriptions seem to have more in common with the active imagination that goes hand in hand with storytelling than with any viral agent identified to date. Preston himself concedes as much in a NY Times interview last month: “That almost certainly didn’t happen.”
OK. So there’s some exaggeration here and some embellishment there and the 3.5 million copies sold is probably responsible for some of the stateside hysteria. But let’s not point too much of the blame in one direction. An invisible pest that moves from person to person and leaves a high mortality rate in its wake is bound to generate a level of fear, with or without The Hot Zone. And when you combine the low science literacy rates in America with its media’s penchant for doom-mongering and narcissistic over-commentary, some version of collective psychosis is all but inevitable. Of course, the recent outbreak has sparked renewed interest in the book, and its infidelity to fact doesn’t help the situation.
In an effort to defuse some of this noise, let’s get to know the real Ebola virus, at least what we’ve gleaned so far. First, some perspective. Yes, Ebola is deadly, and international aid groups should be throwing everything they’ve got at curbing this latest and greatest outbreak. As of 14 November 2014, there have been more than 14,000 reported cases and over 5,000 confirmed deaths (WHO updates this page weekly) since it emerged in Guinea one year ago. But as a matter of pure numbers, Ebola is a minor player on the pathogen roster.
Compare those figures with seasonal flu—the reason many of your coworkers have been calling in sick recently—which infects hundreds of millions and causes 250-500,000 deaths every year (including 20,000 in the U.S. alone). Or norovirus, which infects 267 million people and kills 200,000 annually. Hepatitis C is a virus that currently infects 150 million people worldwide, while malaria kills more than 600,000 a year, or about 68 people per hour. Even rabies accounts for a steady 69,000 deaths per year. Any fear you might have of Ebola should be calibrated against the numbers, which tell us that we’re far more likely to die from lightning, a car accident or a plane crash than we are from Ebola.
Much of that has to do with Ebola’s method of transmission. Contrary to what Preston repeatedly suggests in The Hot Zone, Ebola is not transmitted through the air or by respiratory secretions (i.e., coughing or sneezing), unlike influenza or SARS. Ebola can only be transmitted by direct physical contact with the blood, vomit or feces of an infected person. A cough or a sneeze from an Ebola host doesn’t contain high enough concentrations of the virus to infect someone nearby because Ebola doesn’t aerosolize in the way its airborne counterparts do. This explains why the reports keep flowing in of infected healthcare workers; they are at the highest risk of infection because they’re the ones working with the patients after the incubation period is over and symptoms have surfaced. So unless you find yourself in contact with any of these three fluids of an Ebola victim, you have nothing to worry about.
Many have frowned on science for not having a vaccine ready by the truckloads. This may sound brusque, but given the differential threat of the other viruses mentioned above, Ebola isn’t a top priority. We’ve seen a total of 32 outbreaks over the last 40 years, and yet none have secured a lasting foothold in humans. In contrast, flu and malaria are perennial killers of titanic proportions. Moreover, vaccines and antivirals (like the experimental ZMapp, which co-opts tobacco plants to clone antibodies derived from mice) are painstakingly difficult and costly to produce and must be adapted to the rapid pace of evolution. In the triage of epidemiological exigency, Ebola’s sporadic presence and short-fused temperament simply rank lower next to many other human scourges.
Its tendency to play hopscotch with the human race is also why there is much we still don’t know about Ebola. As Level 4 contagions go, it is deceptively simple. Were you to ogle it under a microscope, you’d see a single strand of RNA that codes for a mere seven proteins, one of which—VP24—has been identified as the key facilitator for disrupting the cell signaling processes involved in immune response. With the key communication lines “cut”, Ebola is allowed free rein and overwhelms the host system before antiviral reinforcements have time to interfere.
The biochemistry is less opaque than Ebola’s origins, however. One of the finer points we’ve yet to work out is zoonotic provenance: in which species did Ebola first arise, and from which host population did it make the jump to us? Was it in the direction of apes-to-humans like HIV, or did it spill over from some other creature whose environment overlaps with ours? The favored culprit is Egyptian fruit bats, which are known to carry not only the sister virus Marburg but antibodies to Ebola. Even so, it could lurk elsewhere in the wild, biding its time until local conditions pave the way for its reemergence. Learning how pathogens jump from one species to another is vitally important to preventing future outbreaks and is a hot topic among research communities today.
Much like this review, the central character of Preston’s fan favorite is the omnipresent virus. The human characters in the book are poorly developed and ultimately forgettable backdrops which fade in and out as Preston heightens the drama around his lurid replicator—that “nonhuman other” for which he prowls in Kitum Cave. You’ll get a few interesting bits about life inside a biosafety facility, but for the most part any factual profile on Ebola is swallowed whole by the embroidery and myriad grotesqueries sprinkled in at the expense of navigating a more careful line between fiction and reality. Take The Hot Zone for what it is: a high-speed medical-mystery thriller meant to make you tremble at the raw power of nature.
For an accessible take on the real “true story” of Ebola virus, you’ll want to check out David Quammen’s Ebola: The Natural and Human History of a Deadly Virus which is an expanded extract from his larger book Spillover: Animal Infections and the Next Human Pandemic. It’s top-notch. Quammen also appeared in a recently updated Radiolab podcast to discuss the current outbreak, if you prefer a quick overview you can load up during your morning commute.
Feature image via ieeyenews
UPDATE 4.5.2015: Since my review last November, the number of deaths from Ebola have more than doubled, and the case count has increased by 75%. (Situation reports published weekly.) Liberia has been inching toward disease-free status with new cases slowing to a trickle, but two new cases on 25 March have delayed that declaration for now. Meanwhile, a half dozen vaccine candidates are in development, a few of which have progressed to Phase I clinical trials. The longer this epidemic is allowed to proceed, the more familiar the pathogen will become with our biology.