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The marquee on my closed neighborhood movie theater reads, “See you on the other side.” I like reading it every day as I pass by on my walk. It causes me to envision life after the coronavirus pandemic. Which is awfully hard to envision now. But it’s out there. When you have a disease and are in a hospital, alone and afraid, intravenous tubes and sensor wires snaking from your body into digital monitors, all you want is to be normal again. You want nothing more than to have a beer in a dusky bar and read a book in amber light. At least that’s all I wanted last year when I was in a hospital, not from a coronavirus. When, this February, I had that beer in a bar with my book, I was profoundly happy. The worst can pass.
With faith, you can ask how life will be on the other side. Will you be changed personally? Will we be changed collectively? The knowledge we’re gaining now is making us different people. Pain demands relief, demands we don’t repeat what produced it. Will the pain of this pandemic point a new way forward? It hasn’t before, as every war attests. This time may be no different. But the pandemic has slipped a piece of knowledge into the body public that may not be easy to repress. It’s an insight scientists and poets have voiced for centuries. We’re not apart from nature, we are nature. The environment is not outside us, it is us. We either act in concert with the environment that gives us life, or the environment takes life away.
Guess which species is the bully? No animal has had the capacity to modify its niche the way we have.
Nothing could better emphasize our union with nature than the lethal coronavirus. It’s crafted by a molecule that’s been omnipresent on Earth for 4 billion years. Ribonucleic acid may not be the first bridge from geochemical to biochemical life, as some scientists have stated. But it’s a catalyst of biological life. It wrote the book on replication. RNA’s signature molecules, nucleotides, code other molecules, proteins, the building blocks of organisms. When RNA’s more chemically stable kin, DNA, arrived on the scene, it outcompeted its ancestor. Primitive organisms assembled into cells and DNA set up shop in their nucleus. It employed its nucleotides to code proteins to compose every tissue in every multicellular species, including us. A shameless opportunist, RNA made itself indispensable in the cellular factory, shuttling information from DNA into the cell’s power plant, where proteins are synthesized.
RNA and DNA had other jobs. They could be stripped down to their nucleotides, swirled inside a sticky protein shell. That gave them the ability to infiltrate any and all species, hijack their reproductive machinery, and propagate in ways that make rabbits look celibate. These freeloading parasites have a name: virus. But viruses are not just destroyers. They wear another evolutionary hat: developers. Viruses “may have originated the DNA replication system of all three cellular domains (archaea, bacteria, eukarya),” writes Luis P. Villareal, founding director of the Center for Virus Research at the University of California, Irvine.1 Their role in nature is so successful that DNA and RNA viruses make up the most abundant biological entities on our planet. More viruses on Earth than stars in the universe, scientists like to say.
Today more RNA than DNA viruses thrive in cells like ours, suggesting how ruthless they’ve remained. RNA viruses generally reproduce faster than DNA viruses, in part because they don’t haul around an extra gene to proofread their molecular merger with others’ DNA. So when the reckless RNA virus finds a new place to dwell, organisms become heartbreak hotels. Once inside a cell, the RNA virus slams the door on the chemical saviors dispatched by cells’ immunity sensors. It hijacks DNA’s replicative powers and fans out by the millions, upending cumulative cellular functions. Like the ability to breathe.
Humans. We love metaphors. They allow us to compare something as complex as viral infection to something as familiar as an Elvis Presley hit. But metaphors for natural processes are seldom accurate. The language is too porous, inviting our anthropomorphic minds to close the gaps. We imagine viruses have an agenda, are driven by an impetus to search and destroy. But nature doesn’t act with intention. It just acts. A virus lives in a cell like a planet revolves around a sun.
Biologists debate whether a virus should be classified as living because it’s a deadbeat on its own; it only comes to life in others. But that assumes an organism is alive apart from its environment. The biochemist and writer Nick Lane points out, “Viruses use their immediate environment to make copies of themselves. But then so do we: We eat other animals or plants, and we breathe in oxygen. Cut us off from our environment, say with a plastic bag over the head, and we die in a few minutes. One could say that we parasitize our environment—like viruses.”2
Our inseparable accord with the environment is why the coronavirus is now in us. Its genomic signature is almost a perfect match with a coronavirus that thrives in bats whose habitats range across the globe. Humans moved into the bats’ territory and the bats’ virus moved into humans. The exchange is just nature doing its thing. “And nature has been doing its thing for 3.75 billion years, when bacteria fought viruses just as we fight them now,” says Shahid Naeem, an upbeat professor of ecology at Columbia University, where he is director of the Earth Institute Center for Environmental Sustainability. If we want to assign blame, it lies with our collectively poor understanding of ecology.
Organisms evolve with uniquely adaptive traits. Bats play many ecological roles. They are pollinators, seed-spreaders, and pest-controllers. They don’t die from the same coronavirus that kills humans because the bat’s anatomy fights the virus to a draw, neutralizing its lethal moves. What’s the deal with the human immune system? We don’t fly. “Bats are flying mammals, which is very unusual,” says Christine K. Johnson, an epidemiologist at the One Health Institute at the University of California, Davis, who studies virus spillover from animals to humans. “They get very high temperatures when they fly, and have evolved immunological features, which humans haven’t, to accommodate those temperatures.”
A viral invasion can overstimulate the chemical responses from a mammal’s immune system to the point where the response itself causes excessive inflammation in tissues. A small protein called a cytokine, which orchestrates cellular responses to foreign invaders, can get over-excited by an aggressive RNA virus, and erupt into a “storm” that destroys normal cellular function—a process physicians have documented in many current coronavirus fatalities. Bats have genetic mechanisms to inhibit that overreaction. Similarly, bat flight requires an increased rate of metabolism. Their wing-flapping action leads to high levels of oxygen-free radicals—a natural byproduct of metabolism—that can damage DNA. As a result, states a 2019 study in the journal Viruses, “bats probably evolved mechanisms to suppress activation of immune response due to damaged DNA generated via flight, thereby leading to reduced inflammation.”3
Bats don’t have better immune systems than humans; just different. Our immune systems evolved for many things, just not flying. Humans do well around the cave fungus Pseudogymnoascus destructans, source of the “white-nose syndrome” that has devastated bats worldwide. Trouble begins when we barge into wildlife habitats with no respect for differences. (Trouble for us and other animals. White-nose syndrome spread in part on cavers’ shoes and clothing, who tracked it from one site to the next.) We mine for gold, develop housing tracts, and plow forests into feedlots. We make other animals’ habitats our own.
Our moralistic brain sees retribution. Karma. A viral outbreak is the wrath that nature heaps on us for bulldozing animals out of their homes. Not so. “We didn’t violate any evolutionary or ecological laws because nature doesn’t care what we do,” Naeem says. Making over the world for ourselves is just humans being the animals we are. “Every species, if they had the upper hand, would transform the world into what it wants,” Naeem says. “Birds build nests, bees build hives, beavers build dams. It’s called niche construction. If domestic cats ruled the world, they would make the world in their image. It would be full of litter trays, lots of birds, lots of mice, and lots of fish.”
But nature isn’t an idyllic land of animal villages constructed by evolution. Species’ niche-building ways have always brought them into contact with each other. “Nature is ruled by processes like competition, predation, and mutualism,” Naeem says. “Some of them are positive, some are negative, some are neutral. That goes for our interactions with the microbial world, including viruses, which range from super beneficial to super harmful.”
Nature has been doing its thing for 3.75 billion years, when bacteria fought viruses as we fight them now.
Ultimately, nature works out a truce. “If the flower tries to short the hummingbird on sugar, the hummingbird is not going to provide it with pollination,” Naeem says. “If the hummingbird sucks up all the nectar and doesn’t do pollination well, it’s going to get pinged as well. Through this kind of back and forth, species hammer out an optimal way of getting along in nature. Evolution winds up finding some middle ground.” Naeem pauses. “If you try to beat up everybody, though, it’s not going to work.”
Guess which species is the bully? “There’s never been any species on this planet in its entire history that has had the capacity to modify its niche the way we have,” Naeem says. Our niche—cities, farms, factories—has made the planet into a zoological Manhattan. Living in close proximity with other species, and their viruses, means we are going to rub shoulders with them. Dense living isn’t for everyone. But a global economy is. And with it comes an intercontinental transportation system. A virus doesn’t have a nationality. It can travel as easily from Arkansas to China as the other way around. A pandemic is an inevitable outcome of our modified niche.
Although nature doesn’t do retribution, our clashes with it have mutual consequences. The exact route of transmission of SARS-CoV-2 from bat to humans remains unmapped. Did the virus pass directly into a person, who may have handled a bat, or through an intermediate animal? What is clear is the first step, which is that a bat shed the virus in some way. University of California, Davis epidemiologist Johnson explains bats shed viruses in their urine, feces, and saliva. They might urinate on fruit or eat a piece of it, and then discard it on the ground, where an animal may eat it. The Nipah virus outbreak in 1999 was spurred by a bat that left behind a piece of fruit that came in contact with a domestic pig and humans. The Ebola outbreaks in the early 2000s in Central Africa likely began when an ape, who became bushmeat for humans, came in contact with a fruit bat’s leftover. “The same thing happened with the Hendra virus in Australia in 1994,” says Johnson. “Horses got infected because fruit bats lived in trees near the horse farm. Domesticated species are often an intermediary between bats and humans, and they amplify the outbreak before it gets to humans.”
Transforming bat niches into our own sends bats scattering—right into our backyards. In a study released this month, Johnson and colleagues show the spillover risk of viruses is the highest among animal species, notably bats, that have expanded their range, due to urbanization and crop production, into human-run landscapes.4 “The ways we’ve altered the landscape have brought a lot of great things to people,” Johnson says. “But that has put wildlife at higher pressures to adapt, and some of them have adapted by moving in with us.”
Pressures on bats have another consequence. Studies indicate physiological and environmental stress can increase viral replication in them and cause them to shed more than they normally do. One study showed bats with white-nose syndrome had “60 times more coronavirus in their intestines” as uninfected bats.5 Despite evidence for an increase in viral replication and shedding in stressed bats, “a direct link to spillover has yet to be established,” concludes a 2019 report in Viruses.3 But it’s safe to say that bats being perpetually driven from their caves into our barns is not ideal for either species.
As my questions ran out for Columbia University’s Naeem, I asked him to put this horrible pandemic in a final ecological light for me.
“We think of ourselves as being resilient and robust, but it takes something like this to realize we’re still a biological entity that’s not capable of totally controlling the world around us,” he says. “Our social system has become so disconnected from nature that we no longer understand we still are a part of it. Breathable air, potable water, productive fields, a stable environment—these all come about because we’re part of this elaborate system, the biosphere. Now we’re suffering environmental consequences like climate change and the loss of food security and viral outbreaks because we’ve forgotten how to integrate our endeavors with nature.”
A 2014 study by a host wildlife ecologists, economists, and evolutionary biologists lays out a plan to stem the tide of emergent infectious diseases, most of which spawned in wildlife. Cases of emergent infectious diseases have practically quadrupled since 1940.6 World leaders could get smart. They could pool money for spillover research, which would identify the hundreds of thousands of potentially lethal viruses in animals. They could coordinate pandemic preparation with international health regulations. They could support animal conservation with barriers that developers can’t cross. The scientists give us 27 years to cut the rise of infectious diseases by 50 percent. After that, the study doesn’t say what the world will look like. I imagine it will look like a hospital right now in New York City.
Patients lie on gurneys in corridors, swaddled in sheets, their faces shrouded by respirators. They’re surrounded by doctors and nurses, desperately trying to revive them. In pain, inconsolable, and alone. I know they want nothing more than to see their family and friends on the other side, to be wheeled out of the hospital and feel normal again. Will they? Will others in the future? It will take tremendous political will to avoid the next pandemic. And it must begin with a reckoning with our relationship with nature. That tiny necklace of RNA tearing through patients’ lungs right now is the world we live in. And have always lived in. We can’t be cut off from the environment. When I see the suffering in hospitals, I can only ask, Do we get it now?
Kevin Berger is the editor of Nautilus.
References
1. Villareal, L.P. The Widespread Evolutionary Significance of Viruses. In Domingo, E., Parrish, C.R., & Hooland, J. (Eds.) Origin and Evolution of Viruses Elsevier, Amsterdam, Netherlands (2008).
2. Lane, N. The Vital Question: Energy, Evolution, and the Origins of Complex Life W.W. Norton, New York, NY (2015).
3. Subudhi, S., Rapin, N., & Misra, V. Immune system modulation and viral persistence in Bats: Understanding viral spillover. Viruses 11, E192 (2019).
4. Johnson, C.K., et al. Global shifts in mammalian population trends reveal key predictors of virus spillover risk. Proceedings of The Royal Society B 287 (2020).
5. Davy, C.M., et al. White-nose syndrome is associated with increased replication of a naturally persisting coronaviruses in bats. Scientific Reports 8, 15508 (2018).
6. Pike, J., Bogich, T., Elwood, S., Finnoff, D.C., & Daszak, P. Economic optimization of a global strategy to address the pandemic threat. Proceedings of the National Academy of Sciences 111, 18519-18523 (2014).
Lead image: AP Photo / Mark Lennihan
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