Chinese officials seized civet cats in a wildlife market in Guangzhou in 2004 to prevent the spread of the SARS virus.

Chinese officials seized civet cats in a wildlife market in Guangzhou in 2004 to prevent the spread of the SARS virus. Dustin Shum/South China Morning Post via Getty Images

Interview

Spillover Warning: How We Can Prevent the Next Pandemic

Author David Quammen has tracked the spillover of viruses from animals to humans for more than a decade. To avoid future pandemics, he says, we must rethink our relationship with nature and recognize how our choices can lead to dangerous disruptions of the natural world.

As the novel coronavirus has emerged and spread around the globe, science writer David Quammen has not been surprised. He’d warned of just such a scenario in his unsettling 2012 book, Spillover, which detailed how — as we continue to disrupt the natural world — viruses are increasingly spreading from wild animal populations to humans.

A global pandemic like Covid-19 was inevitable, Quammen says in an interview with Yale Environment 360. What was not inevitable, given the alerts that scientists have been issuing for a decade or more, was the utter lack of preparedness. “I am surprised at how unprepared we’ve been and how badly we, meaning this [Trump] administration but also state governments, have managed this,” he says.

David Quammen

David Quammen

For his reporting, Quammen has crawled into bat caves with researchers in search of emerging viruses, visited wild animal markets in China that are prime hot spots for viral transfer, and traveled to African villages ravaged by Ebola. The heart of the issue, he tells e360, is “our relationship with the rest of the natural world, which is consumptive, intrusive, and disruptive.”

“All the choices that we make — what we eat, how much we travel, how many children we have, what we buy… ,” he says, “all of these choices have consequences for our contact with the rest of the natural world.”

Yale Environment 360: When you wrote Spillover in 2012, you warned that we were going to face basically the same situation we’re faced with now — a virus that spills over from animals into humans and spreads around the globe. And scientists warned us three years ago about the emerging novel coronavirus. Yet the world now finds itself unprepared for this outbreak. Has that surprised you at all?

David Quammen: Yes, the lack of preparedness is the only thing about this whole situation that has surprised me. I didn’t have any illusions that the people who control the wheels of power and government were listening carefully to the scientists, but I thought they were listening at least enough to have some preparedness. And in this country, of course, I knew that [President] Trump was trying to defund the Centers for Disease Control as much as he could and had gotten rid of the key people on the National Security Council who were in charge of pandemic preparedness.

Still, I am surprised at how unprepared we’ve been and how badly we, meaning this administration but also state governments, have managed this thing. It’s appalling.

e360: You’ve been out in the field with the scientists who go searching for new viruses in wild animal populations. This virus was actually discovered and then identified in China in 2017. How did researchers come upon this virus?

Quammen: Scientists have known that coronaviruses are dangerous because SARS was a coronavirus. Coronaviruses have been one of the groups at the top of the watch list. It has also been known that small bats, insectivorous bats, such as horseshoe bats, carry coronaviruses in some variety, unknown, and that those bats live, among other places, in Southern and Central China where they roost in caves.

“If a bat roosts together with thousands of other bats in these cozy huddles or scrums, that is a great situation for passing viruses.”

So a team from the Wuhan Institute of Virology, among other institutions, led by a woman named Dr. Shi Zhengli, went to caves in Yunnan Province and captured bats. They took blood samples. They looked for coronaviruses, and in 2017, they came out with a paper announcing that they had found a new coronavirus and identified its genome sequence.

e360: It seems like many of these viruses originate in bats. Is there any sense of why that is?

Quammen: A couple of things make bats more likely to seem as though they are overrepresented as the reservoir hosts of these viruses. First of all, bats are an incredibly diverse order of mammals. One in every four species of mammal on the planet is a species of bat. They would naturally seem overrepresented because they are overrepresented in mammal diversity.

Beyond that, there are actual physiological reasons . Bats tend to live a long time — some of them can live 18 to 20 years. If a bat lives 18 to 20 years, and if it roosts together with thousands of other bats in these cozy huddles or scrums on the wall of a cave, 60,000 bats, essentially, in a pileup on the wall of a cave, then that is a great situation for passing viruses from one individual to another endlessly, round and round, so that the virus continues circulating in the bat population.

e360: In the case of novel coronavirus and others, these bats made their way into animal markets and then spread from there to humans. I know you’ve been to one of those markets in China. Can you describe what it was like?

Quammen: I was there during one of the periods of suppression of the [wild animal] trade [after the 2003 SARS outbreak]. But frogs were still legal. Turtles were still legal. I didn’t see bats. But I saw a ton of wild birds of all sorts that had been captured, not for pets but for food, and all caged in a great jumble, with water flowing and blood flowing, and butchery happening in a pretty unhygienic environment.

Bats for sale in a market on Sulawesi island in Indonesia in February.

Bats for sale in a market on Sulawesi island in Indonesia in February. Ronny Adolof Buol / AFP via Getty Images

There is a vogue in China now for what’s called “wild flavor.” That’s our English translation. There’s this vogue for eating wild animals: porcupines, bamboo rats, palm civets, pangolins, bats, frogs, snakes, tortoises, turtles, et cetera, and more. There are these markets that periodically operate in the open. Then sometimes, the Chinese enact regulations against them, which they did after the SARS outbreak. This wild animal trade was driven underground. It never disappeared, but it was happening out the back doors of restaurants and other places. Some people say, “Well, this is an ancient tradition in China. This is going to take a lot of education to move people away from it.” But I have a Chinese colleague who looked into this and read some of the ancient Chinese sources. Those ancient Chinese sources were saying the opposite. They were saying, “Don’t eat wild animals. You’re liable to get sick. No, wild animals are not healthy.”

I think it’s a myth that this is an ancient and revered tradition. What it is more likely is a vogue. It’s not like what we call bushmeat in Africa, which to a considerable degree is consumed by people in the countryside, people in villages who live close to the forest who desperately need protein. It’s true that bushmeat in Africa is also traded commercially. There are chimpanzees being killed, and shipped, or trucked to capital cities where people with money pay fancy prices to be able to eat chimpanzee meat. It’s a vogue in parts of Africa. But of course, in Montana, where I live, it’s also a vogue. We eat deer and elk, and we call it wild game.

e360: What underlies this whole issue, really, is our relationship with nature, how it’s changed, and the way we keep pushing more and more into habitat and increasing human contact with animals. Do you see that as the heart of the issue?

Quammen: That is absolutely the heart of the issue, yes. Our relationship with the rest of the natural world, which is consumptive, and intrusive, and disruptive. Those things shake loose viruses from their natural hosts. All these wild animals carry their own unique viruses. When we go into a tropical forest with its great diversity, and we start cutting down trees, and capturing animals, or killing animals for food, then we offer those viruses the opportunity to become our viruses, to jump into us and find a new host, a much more abundant host. And when a virus moves from an infected animal into a human, it’s won the sweepstakes. It can now spread around the world and become one of the world’s most successful viruses, which this coronavirus now is.

“The problem is that when there’s no outbreak, there’s no interest in discovering new viruses, and there’s no money for it.”

All the choices that we make — what we eat, how much we travel, how much energy we consume, how many children we have, where we live, what we buy, whether we have a cell phone and a laptop computer — all of these choices have consequences for our contact with the rest of the natural world. For instance, cell phones. Cell phones contain tantalum capacitors. Tantalum comes from the mineral coltan, which is mined in just a few places, one of which is the eastern Democratic Republic of the Congo in an area near Itombwe Nature Reserve, which has got lowland gorillas and bats and all sorts of other biological diversity. By owning a cell phone, I am essentially commissioning miners to go into that place and mine coltan for my phone. While they’re there, what are they going to eat? Well, they’re probably going to eat bushmeat. I realize that, not just by the number of miles that I fly in a year but by some of my basic consumer choices, I bear some of the responsibility.

e360: Why don’t these viruses affect their animal hosts, but they do affect humans?

Quammen: The reason they don’t seem to affect their animal hosts is because they probably, in most cases, have lived in that animal host for thousands or millions of years. There has been a coadaptation. The animal host is called the reservoir host, and the usual relationship between a virus and a reservoir host is that the virus exists at relatively low levels. It’s not fulminating inside the reservoir hosts’ individual bodies. It’s not replicating as fast as it might. It’s not causing organ shutdown in that animal. It’s just living there.

Then it happens to spill over into a new host, say, a human. It’s a new environment. If the virus has broad adaptive capacity, a relatively wide niche, it might already be adapted, and it finds that, okay, I can get along in this other mammal pretty well. I can get into the cells of this new mammal, this one that’s wearing a wristwatch and clothes. I can replicate in that first cell and come busting out of that cell, and I can get into another one. And I can even do that in the respiratory tract which means, holy cow, now I have the opportunity to come flying out of this host the next time I succeed in making him cough, and maybe I can get into a new host. Gloriosky! I’ve succeeded.

Now I’m a human virus traveling from one human to another. But it’s a new relationship. I don’t have an old co-evolved relationship with this host. I’m going to replicate as fast as I damn well can, and make myself abundant and seize this new opportunity for vast, evolutionary success by going from one host to another at high levels. Before you know it, I’m going to be one of the most successful viruses in the world. It’s all ecology and evolutionary biology.

The shuttered Huanan Seafood Wholesale Market in Wuhan, where the Covid-19 virus was detected in January.

The shuttered Huanan Seafood Wholesale Market in Wuhan, where the Covid-19 virus was detected in January. Hector Retamal/AFP via Getty Images

e360: This whole subject seems to fuse the two overarching topics of your work, which are ecology and evolution. Do you see it that way?

Quammen: Absolutely. That’s the reason I got interested in this whole crazy field 20 years ago or so. I started reading about Ebola, and I realized there was the question of Ebola and where it goes when it’s not killing humans. Oh, it’s got a reservoir host. What’s the reservoir host? Well, we don’t know. We haven’t found it yet. There’s a mystery story there. I realized that it was all about ecology and evolutionary biology, the ecology of scary viruses, and the evolutionary biology of scary viruses, and the hosts that they live in. That was right over the plate for me, that was in my wheelhouse of evolutionary biology.

e360: You’ve been out with the scientists who are virus hunters, people who are looking for the origins of these viruses. Funding for this kind of work, not to mention for preparedness for outbreaks, has been cut. There’s not enough?

Quammen: No, there’s not enough. There’s never enough money for this kind of important research. Some call it viral discovery, finding out what’s out there that might be dangerous. The problem is that when there’s no outbreak, there’s no interest in discovering new viruses, and there’s no money for it. When there’s an outbreak, it’s a medical emergency, so you can’t get money to go out there and do the basic ecological research to identify the host. If there are people dying in Liberia, Sierra Leone, or Guinea, you can’t go in there with your white suits and say, “Oh, we’re not dealing with people. We want to go into the forest, and trap some bats, and take blood samples.”

There’s never enough money. There are organizations that are doing this and doing wonderful work. But there’s not enough, just the way there’s not enough money for actual preparedness for various reasons, including the fact that if you spend $5 billion on preparedness against the pandemic and then the pandemic doesn’t happen during your first presidential term, then when you run for your second term, people are going to criticize you for having wasted that money.

“We can do some things: cutting down on the wild animal trade and cutting down on our disruption of diverse ecosystems.”

e360: Is there anything we can do to reduce the chances of the next big pandemic or at least be better prepared for it?

Quammen: Yes. We can reduce the chances both of spillovers occurring and of spillovers turning into outbreaks, epidemics, pandemics. The less disruptive contact that we have with wild animals, the less chance there is for there to be spillover of a dangerous new virus into the first human. We can do some things about that: cutting down on the wild animal trade, cutting down probably on the meat that we eat, cutting down on our disruption of wild animals and diverse ecosystems. We’ll then bring a lessening of the opportunities for these viruses to spill over into a single human. Once a spillover happens, we can improve our scientific and technological ways of detecting that very quickly, and our public health measures for isolating an outbreak before it becomes an epidemic.

The big events don’t happen every year, but they may happen once every 10 years. A new, really dangerous virus comes blasting out of some particular country. It gets on airplanes with people, and it rides around the world. When we know this virus is getting loose, our responses at that point can be much better. We can have real-time detecting, screening of people, positive or negative, at airport security points, if we develop the technology to do that. I thought that was going to be done by now. I heard about that 10 years ago, and it still hasn’t happened.

e360: Do you think that this will finally spur action on that?

Quammen: I hope so, but I’m not confident. Still, I am hopeful that this should make a difference, that this will shock us into better preparedness.

Roger Cohn is the editor of Yale Environment 360.

This interview has been edited for length and clarity.