Spillover, revisited

“You’re overreacting. Look at how many people die from the flu every year,” my mom said. This was a couple weeks ago, and we were on the phone discussing my plans to visit home. My parents live in Houston, I live in Portland, Oregon, and my annual work trip to SXSW in Austin presented an all too rare opportunity to visit Texas. I was expressing my doubts that the trip was going to happen. There was this new coronavirus, and it sounded serious.

My mom, like many at the time and some even now, thought the media might be blowing the whole thing out of proportion. She mentioned my own writing, which has often focused on debunking media-driven health panics. Could this be more of the same? At first, it seemed unthinkable to cancel an event as massive as SXSW. Then it began to feel inevitable. Today, the idea that they could have done anything less feels recklessly irresponsible.

The events I’d been planning for months were called off, but I still had plane tickets and an expensive, non-refundable hotel room. I still had parents who wanted me to visit. I still had a hunger for breakfast tacos and Texas barbecue. But I also had vague yet evocative memories of a book I’d read eight years ago, a book in which ordinary people pick up extraordinary diseases, with often fatal consequences for themselves, their loved ones, and the doctors and nurses who care for them. Transporting my body and its invisible passengers into my parents’ house, where any sneeze, cough, or lick from an affectionate terrier could spread contagion, didn’t feel worth the risk. And so, as my flight departed to Austin, I stayed home revisiting David Quammen’s prescient book, Spillover.

David Quammen is among a handful of authors whose books I’ll order as soon as they’re announced, regardless of whether I have any previous interest in the subject matter. (Perceptions of man-eating predators? I will – hopefully – never be devoured by a bear, but Monster of God was an engaging read nonetheless.) His 2012 book, Spillover, is devoted entirely to infections that make the leap from other animals into humans. In technical parlance, “zoonosis.” The list of previous zoonoses is long: AIDS, Ebola, Marburg, rabies, Nipah encephalitis, Lyme disease, too many more to mention. Some, like flu, have become an ever-fluctuating part of our familiar viral landscape. Others, like SARS, flare up, run their course with terrifying intensity, and burn out. Our lives move on. But Quammen’s book wasn’t intended as a curious catalogue of past events. It was a warning. Zoonosis, he cautioned, “is a word of the future, destined for use in the twenty-first century.” Eight years later, that future has arrived.

Is this new coronavirus the “Next Big One” that epidemiologists have been fearing? If not, it’s certainly big enough, and it’s exposing how unprepared we are for it. Though Spillover is too dense to cover fully, here are three points that stood out while re-reading it during the current pandemic.

“Everything comes from somewhere”

One of the things I appreciate about Quammen’s books is that he situates his topics in evolutionary and ecological contexts. “Although infectious disease can seem grisly and dreadful, under ordinary conditions it’s every bit as natural as what lions do to wildebeests and zebras, or what owls do to mice.” We are not separate from nature. We are not even fully human; each of us is an ecological niche unto ourselves, home to uncountable microbes. So is every other creature. Through the long, relentless pressure of evolution, most of these relationships become manageable, sometimes even beneficial. Occasionally these microbes find themselves outside of the reservoir hosts to which they’ve become adapted. And then? A dead end, typically. But also opportunity. Nearly 8 billion opportunities in the case of humans, an efflorescence of new environments packed densely into cities and connected by global travel. And while most of us in wealthier countries rarely come into contact with live animals other than our pets, we interact with them indirectly through farming, trade, and encroachment into wild habitats. “Shake a tree,” as Quammen writes, “and things fall out.”

From a microbe’s eye view, we humans are high-risk, high-reward. They may infect our bodies and ravage us so thoroughly that they are unable to spread, their path blocked by human response strategies or their own excessive virulence. That’s the Ebola story, so far: a handful outbreaks, extremely high fatality rates, but ultimately, containment. In other conditions, the microbe may take hold and find itself capable of transmitting from host to host indefinitely, keeping the humans it infects alive long enough to spread it to others. That’s HIV, a virus that jumped from the blood of other primates to a person. The circumstances are contingent; it might have happened lots of times, eventually fizzling out. It only had to break through once. (In actuality, it probably succeeded multiple times.)

You don’t have to slaughter a chimp or eat a bat for zoonosis to happen. Disease could spring from racehorses (Hendra), pigs and chickens (swine and avian flu), domesticated goats (Q Fever), cattle (“mad cow”), parrots (psittacosis), ticks (Lyme disease), or Old Yeller (rabies). Reasonable steps can be taken to prevent spillover, and the present epidemic will likely result in some reflection on how to do so, but there’s no way to stop it entirely. The next disease is out there, uncharted. The question is how to prepare for it.

SARS should have prepared us

Eight years after first reading Spillover, there were a few specific cases described within it that lingered in my memory. The Australian horse trainer who came down with Hendra. The Dutch tourist who picked up Marburg during a ten-minute venture into a Ugandan cave. And most relevant to the current epidemic, the “superspreaders” who inadvertently transmitted SARS far beyond its initial entry into the human population.

A surprising number of these cases can be traced to a single hotel in Hong Kong, where a professor from Guangzhou arrived for a wedding. He’d been ill two weeks before, then felt well enough to travel. At the hotel, he felt sick again. He stayed on the ninth floor. So did a seventy-eight-year-old grandmother from Toronto, who overlapped with him for one night. So did a young woman from Singapore. Within a few weeks, the professor had died. The grandmother died, too, after flying the virus back to Canada, where it killed thirty-one. The young woman returned to Singapore. She survived, but her mother, father, uncle, and pastor did not. A woman infected by the grandmother brought SARS to the Philippines; a man infected by the young woman took it to Germany. In the end, SARS infected 8,098 people and took the lives of 774.

This web of infections, vaguely remembered, is what was on my mind as I contemplated my forthcoming trip to Texas. The United States had restricted travel from China, but the new coronavirus was already here. Never mind the Chinese; I fit the profile of a superspreader. I’d just been to New York, cramming onto subways, squeezing into airplanes, massing at the rails of the Staten Island Ferry as we passed the Statue of Liberty. Then back to Portland, where I went to bars and restaurants, played soccer. And then? To Austin, where I would interact with thousands of other travelers who had non-refundable tickets? And on to the home of my parents, who are in their sixties? No, thank you. Better to stay in Oregon reading popular science books.

Another thing about SARS: It was also caused by a coronavirus, SARS-CoV, namesake for the virus you’re currently worried about, SARS-CoV-2. As frightening as the original SARS outbreak was, its spread was limited. Perhaps that’s part of why some people are downplaying risks now. We’ve had outbreaks like this before, and they weren’t that bad in the scheme of things. That’s the wrong way to think about it. A better question to ask is, “Under what conditions could SARS have been much, much worse?”

The fortunate thing about SARS is that the infected typically endured recognizable symptoms before they became highly contagious. That made it possible to contain it. “This was an enormously consequential factor in the SARS episode – not just lucky but salvational,” writes Quammen. For some other viruses, such as the flu, infectiousness can precede symptoms; that’s part of why they spread so easily. So, what’s scarier than SARS? SARS that spreads like the flu.

That’s not exactly what we’re facing now, but there are similarities. Toward the end of Spillover, Quammen recounts an interview with epidemiologist Donald S. Burke, who had given a lecture back in 1997 on the groups of viruses most likely to lead to the next pandemic. Coronaviruses stood out as a probable candidate even then, given their propensities toward infecting animals and rapidly evolving. The genomes of coronaviruses are encoded in error-prone RNA. That means they mutate often; they adapt, they evolve, the replicate in huge numbers. We were warned about this before SARS. SARS proved that the danger was real. Less than two decades after the initial SARS outbreak, the danger is here.

What we do now matters

I’m not writing this post to sound fatalistic. Yes, zoonoses are to some degree inevitable (though we can alter practices to prevent them). Yes, a bad one has arrived. But there’s a reason there are nearly eight billion of us: We are smart and we can change our behavior in light of new information. Toward the end of his book, Quammen considers how much that matters. “[Individual] effort, individual discernment, individual choice can have huge effects in averting the catastrophes that might otherwise sweep through a herd.”

Here in the United States, we’ve squandered our early opportunities to prevent the spread of this new coronavirus. Due to a lack of testing, we’re not even sure how many people have been infected. What happens next depends on a multitude of factors: how deadly the virus turns out to be, how many people get it (especially in vulnerable populations), and whether our hospital systems are able to deliver care without being overwhelmed by new patients. Under the rosiest estimates, deaths will be in the hundreds or thousands. If things don’t go well? Hundreds of thousands. If this goes very badly? More than a million.

The worst-case scenarios are not inevitable. But they are plausible. They are realistic. You should take them seriously. Even now, I feel like many people I talk to or interact with online are still complacent about how rapidly things can change. Here are the two points I think cannot be emphasized enough:

First, this is not something that only happens over there, or to other people. It’s not just the flu. You need to be thinking of this as something that could very well take the life of someone you care about.

Second, think about what you, as an individual, can do to prevent the worst-case scenarios from happening. Don’t be a superspreader. Try not to be a mediumspreader, either. Cancel your trip, cancel your events, cancel your parties. Work from home, if you can. Practice social distancing. How extreme? Honestly, I can’t tell you, but do think about it. If you’re reading this on your phone while waiting in line to get into a crowded bar, you’re doing it wrong.

What’s next?

What’s next, when the worst of this is over? I don’t mean next for this virus, or even for diseases generally. I mean what other disasters have we been warned about that many of us blithely ignore? That’s another thing I think about reading Spillover now. There’s climate change, obviously, which could spiral out in all sorts of terrible ways. Living in the Pacific Northwest, something more specific comes to mind: the other Next Big One, the earthquake and tsunami that will likely be triggered by the next great shift in the Cascadia subduction zone.

When Americans think of destructive earthquakes, we generally think of the San Andreas Faultline because it’s the most active. Due to all that activity, the cities along it are prepared. Little earthquakes and big earthquakes happen with too much frequency to ignore. The Cascadia subduction zone is different. Until fairly recently, scientists didn’t even recognize it as seismically active. That stillness belied a more frightening truth: The pressure is building up. Rather than releasing it gradually and actively, like the San Andreas, the CSZ releases it all at once in massively destructive megaquakes.

Based on current estimates, these megaquakes occur about every 243 years. The last one has been dated precisely to January of 1700. That’s… 320 years ago. You get the picture. I won’t go into detail here, but you can read grim predictions of what’s coming. Outside magazine devoted a feature to it in 2011. The New Yorker in 2015. Vice in 2016. The narrative structures differ but the basic story is always the same. The megaquake is coming and it’s going to be very, very bad.

Like many people living in the region, I read these stories when they were published. And like many of us, I haven’t done enough to prepare. There’s a suggestive parallel to COVID-19. Places with recent experience of respiratory disease outbreaks, particularly in Asia, knew to take it seriously and had plans in place for dealing with it. It’s similar to how cities that experience minor earthquakes are more prepared for the big ones. In the case of the Cascadia subduction zone, we are not the places prepared for coronavirus like Taiwan or Hong Kong or Taiwan. We’re Italy or the US. If you live in the Pacific Northwest and are currently lamenting the hardship of missing events or scrambling to find toilet paper because of the current epidemic, start thinking about what you can do now to be ready for the next disaster. We can’t say nobody warned us.