by Sonia Shah
So why do some pathogens provoke yawns while others trigger panic? It may have to do with the way they disrupt or conform to the popular conception of pathogens. This conception is clear from the way we talk about disease. The reigning metaphor, in medicine as in the culture at large, is war. We “attack” illness, we “wage war” on disease, we “arm” ourselves with medicines. “Pandemic disease and war,” as The Economist put it, “are so similar.” But the war we’re waging is not against enemies that are elusive or forbidding; on the contrary, they’re cast as easy to conquer. Complex, resilient pathogens such as malaria are seen as easily foiled. All it takes is a few dollars. (As one charitable organization put it, “For just $10, you can … save a life.”) Victory in the war against pathogens is ours, Microsoft cofounder Bill Gates argued in the wake of the 2014 Ebola epidemic. All we have to do is try a little bit harder.20
In this popular formulation, we imagine ourselves the victors of a winnable war against pathogens. That may be why the most frightening pathogens are those that seem invulnerable to our armaments, even when they aren’t actually threatening to us, like Ebola. The virus loomed over our microbial war machine. During the months of Ebolanoia, there was no vaccine to prevent Ebola, no treatment to cure it. It seemed that even sophisticated Western palliative care—round-the-clock nursing, ventilators, and the like—would not make much difference in the course of the infection. Since Ebola’s untamable nature was at the root of the panic, it didn’t matter that Ebola is easily and simply avoided. The very fact of its existence disturbed. Ebola was the red six of spades, a painted clown in a darkened cellar: unexpected, unfathomable, terrifying.
This also explains why Lyme, dengue, and rabies, despite being more threatening and burdensome, are considered less scary. Our chemicals can, in theory, vanquish all three. As my students told me, getting a tick bite in Lyme disease country is no big deal: you just pop a course of the antibiotic doxycycline. Both Lyme and dengue are carried by insects, which are vulnerable to a range of lethal and widely available insecticides. And the vaccine against rabies is 100 percent effective. It doesn’t seem to matter that we may not actually have these pathogens under control: the existence of a weapon that can be used against them provides the comforting illusion of mastery.
Besides shaping our expectations about the risks that pathogens pose to us, casting certain microbes as enemies obscures the fluidity of their disease-causing capacities and our own complicity in nurturing them. Pathogens become something separate, with fundamentally opposed interests that are unresponsive to us. They are simply our nemeses. And yet, the virulence of even a pandemic-causing pathogen like Vibrio cholerae depends entirely on its context. In the body, it’s a pathogen; floating in some warm estuary, it’s a productive member of a harmonious ecosystem. And much of its transformation from harmless microbe to virulent pathogen has to do with our own activities. We turned it into an enemy ourselves.
The simplistic enemy-victor dichotomy with which we often approach pathogens can’t capture this complexity. The result is reactions to pathogens that range from futile paroxysms of fear to lethal apathy.
What we need instead is sustained engagement, with both the formidable threat that pathogens pose and our own critical role in shaping it. That is to say, we need to transcend the simplistic enemy-victor dichotomy and develop a new way of thinking about microbes and our role in the microbial world.
It’s already started to happen. The idea that there are “good germs,” which are beneficial to human health, and not only “bad germs,” has filtered into public consciousness. New ideas about the nature of human health as signifying more than brute victory over pathogenic enemies have started to gain ground, too. The One Health movement, spearheaded by organizations such as Peter Daszak’s EcoHealth Alliance, argues that human health is linked to the health of wildlife, livestock, and the ecosystem. In 2007, both the American Medical Association and the American Veterinary Medical Association passed resolutions recognizing the concept, and scientists from the Institute of Medicine, the Centers for Disease Control, and the WHO have signed on. Let’s hope that these new ideas about disease will lead to a more honest reckoning with pathogens and the risk they pose. Ultimately, preventing pandemics will require reorganizing human activities that aggravate them. Recognizing the responsive dynamism of the microbial world and our own connection to it is a critical first step.
Of course, reimagining our role in the microbial world—which is to say, reimagining our place in nature—is hardly a quick fix to the menace of pandemics. It’s more likely a decades-long, generational project. In the meantime, more immediate measures of pandemic protection will be required.
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If we can’t prevent pandemics altogether, the next best thing is to detect them as quickly as possible.
This will require strengthening and expanding the present system of disease surveillance, which is inadequate in several ways. For one, the system is slow and passive. It’s triggered only when pathogens make their presence obvious by causing outbreaks. In the United States, the Centers for Disease Control maintain a continually amended list of eighty or so infectious diseases, from syphilis to yellow fever. If a clinician happens upon a patient with one of these “notifiable” diseases, he or she is supposed to inform state-level public-health authorities, who pass on the information to national public-health authorities.21 If the outbreak has the potential of crossing borders, national authorities must report it to the WHO within twenty-four hours, according to the agency’s 2007 “International Health Regulations.”22
Even when this system works, it’s not fast enough. By the time the alarm is triggered, pathogens have already adapted to the human body and cases have already started to grow exponentially. The containment effort required to contain the pathogen will necessarily be large and urgent.
By the time the containment effort began in West Africa in 2014, Ebola had been brewing for months (and possibly much longer than that) in remote forest villages in Guinea. Each victim had infected his or her contacts, and those contacts in turn had infected their contacts, and so on for several iterations, each wave of new infections exponentially larger than the last. Disrupting transmission could have been straightforward—each contact has to be tracked and isolated for Ebola’s three-week incubation period—but Ebola had ignited so many concurrent chains of transmission that identifying and isolating all of their potentially exposed contacts had become impossible.23 By mid-September, when the United States announced plans to send its military to build Ebola treatment units in Liberia, the epidemic there had already peaked. Ultimately, the units they built treated a grand total of twenty-eight patients. Nine of the eleven facilities failed to treat a single one.24
Extravagant and only partially effective measures to contain other new pathogens are similarly the result of tardiness. Since H5N1 was not stamped out when it first emerged in the late 1990s, it now regularly plagues poultry flocks around the world. In Hong Kong, authorities slaughter every unsold chicken in their markets nightly in an attempt to contain it.25 Because the SARS virus was not noticed until it had spread into south China’s massive wet markets and started sickening people, containing it required muscular quarantines and travel restrictions that bled Asia’s tourism industry of more than $25 billion.26 Because dengue, West Nile virus, and other vectorborne diseases were not checked before they established footholds across the United States, expensive and controversial campaigns of aerial spraying of insecticides are now de rigueur in many U.S. cities.27 Even when controlling a disease outbreak requires only the cheapest, easiest fixes—like rehydration therapy for cholera—waiting too long makes it a lot harder. The cholera outbreak in Haiti grew so fast that Doctors Without Borders tapped out the entire global supply of intravenous rehydration fluids.28 The mismatch between the way epidemics expand and the rollout of even the most well-coordinated containment effort is inevitable: epidemics grow exponentially while our ability to respond proceeds linearl
y, at best.
The problem is not just that the present surveillance system is slow and passive. It’s also riddled with holes. The system gets activated only when a person infected with a notifiable disease arrives at a doctor’s office. But that’s a reliable switch only if clinicians are trained to detect and report new diseases and their services are readily available across the globe. Neither is the case. People often fail to visit doctors when they’re ill. For many, it’s too expensive. For others, it’s too much trouble. And even when they do anyway, doctors often don’t bother diagnosing strange conditions, or reporting them either. I saw this in action myself. A few summers ago, I’d visited my doctor during a debilitating week-long bout of watery diarrhea and vomiting. Rita Colwell speculated that I’d contracted some kind of vibrio infection. But my doctor responded like many probably do when faced with a patient with a strange but likely self-limiting illness they can’t easily treat. He didn’t order a lab analysis or notify any authorities, though vibrio infections are “notifiable.” He shrugged his shoulders. “Probably just some bug,” he said, and sent me on my way. Anyone in a similar situation who had been an early victim of a new pathogen would have strolled through the disease surveillance system unnoticed.
There are gaps where no one is watching at all. As of this writing, truckloads of foods and armies of insects carry disease across borders, for the most part free of scrutiny. Hardly anyone tracks the spread of invasive disease-carrying vectors, such as the Asian tiger mosquito, which first arrived in the United States in the mid-1980s. Entomologists proposed containing it before it spread but failed to garner sufficient interest. Today, the mosquito carries dengue and other diseases, including new mutant strains of a virus called chikungunya, which established itself in the Americas in 2013.29
In many countries, even the most rudimentary surveillance is scarce. As of 2013, only 80 of the WHO’s 193 member nations had the surveillance capacity to fulfill their WHO-mandated requirements. Antibiotic-resistant pathogens such as NDM-1 are being found basically by accident. There’s no national surveillance to track the bug in India. In most avian-flu-affected countries, livestock are not monitored for signs of the virus. Nor are humans, for that matter.30
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Fixing the present surveillance system is no small task: it will require easy and affordable health care for people everywhere. A network of clinics, staffed with health-care workers trained to recognize and report new pathogens, could do the trick. At the same time, the surveillance system needs to be significantly expanded. Instead of relying solely on sick people visiting doctors, we can actively search for signs of incipient pandemics.
Obviously it’s not possible to surveil every microbe with pandemic potential. Nor is it possible to focus in on a few, for there’s no way to know which microbe will cause the next pandemic. But the probability of new pandemic-causing pathogens emerging is not uniform across the globe. There are certain “hot spots” where it’s most likely to happen, places where wild habitat is being invaded in new and accelerated ways, crowded slums are booming, factory farms are growing, and air connections are expanding. By actively surveilling these hot spots—and the “sentinel” populations that interact with them—we can zero in on the places most likely to hatch new pandemic-causing pathogens. This kind of active surveillance is already under way. Scientists from the University of Hong Kong, for example, collect hundreds of samples of pig and bird feces monthly from wholesale markets, wildlife preserves, pet shops, and slaughterhouses across Hong Kong. At the blindingly white labs of the Li Ka Shing Institute of Health Sciences, scientists pore over the samples for early signs of pathogens with pandemic potential.31 USAID’s Emerging Pandemic Threats program, founded in 2010, coordinates active surveillance programs in hot spots such as the Congo basin in East and Central Africa, the Mekong region in Southeast Asia, the Amazon in South America, and the Gangetic plain in South Asia.32 The International Society of Travel Medicine’s GeoSentinel program collects information about travelers, who act like canaries in the coal mine for emerging disease, from more than two hundred travel and tropical disease clinics.33
A handful of organizations conduct active surveillance for signs of new pathogens in the general population, too. A few U.S. states comb through a continuous stream of data on the “chief complaint” of patients arriving in local emergency rooms, along with data on sales of thermometers and antivirals from pharmacies, for signals that might indicate an impending outbreak. Organizations such as HealthMap and Ascel Bio analyze social media and other online sources to do the same.34
These new active surveillance projects have already proved that they can identify outbreaks faster than the traditional passive surveillance system. HealthMap detected the 2014 Ebola outbreak in West Africa nine days before the World Health Organization broke the news. Ascel Bio’s James Wilson detected the outbreak of cholera in Haiti weeks before official reports appeared. Active surveillance of hot spots has even fingered new spillover pathogens before they’ve infected humans at all. In 2012, an active surveillance program founded by the Stanford University virologist Nathan Wolfe uncovered Bas-Congo virus, a novel virus that can cause Ebola-like hemorrhagic fever, in the Democratic Republic of Congo. Earlier efforts by Wolfe, surveilling blood samples collected by bushmeat hunters and wet-market sellers, uncovered several other new microbes, including one called simian foamy virus and another called simian T-lymphotropic virus, both of which have started crossing over into humans.35
The risk of epidemics could even be predicted the way meteorologists predict the risk of storms. Weather forecasts and satellite data on chlorophyll signatures could help predict outbreaks of malaria, tickborne disease, and cholera. Thanks to the plummeting price of genetic sequencing, the genomes of the microbes around us—on our computers and toilet handles, and in sewage—can be rapidly and cheaply identified, as the computational biologist Eric Schadt has done, to create microbial maps. Those maps could help scientists pinpoint microbial signatures that precede outbreaks, too.36
What emerges from these disparate projects, stitched together alongside beefed-up surveillance based on traditional methods, is a kind of global immune system. It could detect pandemic-worthy pathogens before they hop on flights and get swept up in population movements, pinpointing the next HIV, the next cholera, and the next Ebola before they start to spread.37 For some enthusiasts, such a system would allow societies to continue doing all the things that make pandemics more likely without suffering the consequences. “I believe you can have your cake and eat it too,” the emerging-disease expert Peter Daszak says. “It’s not like you have to stop eating meat. Or stop eating spinach,” he says, or stop flying in airplanes, or eating food from across the globe, or any of the novel modern behaviors that enhance pathogens’ ability to spread. “You can do that. But you can also understand there’s a risk. [Then] you have to insure against that risk,” he says, by helping to pay for a global system of disease surveillance.38 A tax on air travel of 1 percent could cover the bill.39 A global pandemic insurance fund could disburse the money necessary to respond to these early alarms, the same way that disaster insurance policies pay out when hurricanes and earthquakes strike. The World Bank and the African Union started to discuss establishing such a fund in the spring of 2015.40
It’s an appealingly technocratic approach. Early notice makes possible all kinds of more efficient containment and mitigation. We could prevent some epidemics and more effectively prepare to withstand others. But even if such a global surveillance system can be built, it will work only if it translates into people actually using the information to do something about it. And as challenging as building an active global surveillance system will be, ensuring that people act will require an even more far-reaching global project.
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The remote fishing village of Belle-Anse, on the southwestern coast of Haiti, is like countless other towns and villages where the world’s poor live, ostensibly connected to the global economy
and yet brutally isolated. It’s about fifty miles from Port-au-Prince. I made the trip in the summer of 2013. It began in a thirty-year-old Nissan minivan, built to accommodate around eight passengers but carrying nearly twenty that day, including a couple with a small whimpering child and a man with a surprisingly sedate chicken on his lap. The minivan took us over the mountains on steep, narrow, winding roads, discharging us at a dusty lot in the foothills by the coast. But that was just the beginning of the journey. An hour-long motorcycle ride to the shore followed, and then, because the road to Belle-Anse is impassable, another hour zooming across long, wide swells on a fifteen-foot skiff with an outboard motor tied to its stern with a frayed bit of rope.
It took us eight hours to get to Belle-Anse from the capital city. It took cholera about a year. The epidemic enveloped most of the country in 2010 but didn’t reach Belle-Anse until 2011. Its arrival was not only predictable: it had been predicted, using many of the digitally enhanced techniques that will power the new active global surveillance system. There’d been a huge influx of NGOs onto the island before the epidemic started, due to the earthquake that had occurred earlier in the year. When cholera broke out, they used all the technology at their disposal to track its spread. The epidemiologist Jim Wilson and his team trolled Twitter feeds and handed out their cell numbers to local people across the country. “We would see cholera just marching down the highway,” he remembered.41 Volunteers of all kinds had mapped the entire country, “down to each stray dog,” one aid worker said. A Swedish NGO, in collaboration with the local mobile phone company, tracked people’s SIM cards in their phones to map their movements so that they could predict where cholera would hit next. As an early trial of the kind of active disease surveillance system that could be extended globally, it worked beautifully. Cholera arrived in Belle-Anse in 2011 as the Twitter charters and the SIM card trackers watched.42