Some experts have hypothesized that the novel coronavirus made the jump from animals to humans in China’s wet markets, just like SARS before it. Unsurprisingly, many people are furious that the markets, which were closed in the immediate wake of the outbreak in China, are already reopening. It’s easy to point the finger at these “foreign” places and blame them for generating pandemics. But doing that ignores one crucial fact: The way people eat all around the world — including in the US — is a major risk factor for pandemics, too.

That’s because we eat a ton of meat, and the vast majority of it comes from factory farms. In these huge industrialized facilities that supply more than 90 percent of meat globally — and around 99 percent of America’s meat — animals are tightly packed together and live under harsh and unsanitary conditions.

“When we overcrowd animals by the thousands, in cramped football-field-size sheds, to lie beak to beak or snout to snout, and there’s stress crippling their immune systems, and there’s ammonia from the decomposing waste burning their lungs, and there’s a lack of fresh air and sunlight — put all these factors together and you have a perfect-storm environment for the emergence and spread of disease,“ said Michael Greger, the author of Bird Flu: A Virus of Our Own Hatching.

To make matters worse, selection for specific genes in farmed animals (for desirable traits like large chicken breasts) has made these animals almost genetically identical. That means that a virus can easily spread from animal to animal without encountering any genetic variants that might stop it in its tracks. As it rips through a flock or herd, the virus can grow even more virulent.

Greger puts it bluntly: “If you actually want to create global pandemics, then build factory farms.”

For years, expert bodies like the World Health Organization and the Centers for Disease Control and Prevention have been warning that most emerging infectious diseases come from animals and that our industrialized farming practices are ratcheting up the risk. “Livestock health is the weakest link in our global health chain,” noted the Food and Agriculture Organization of the United Nations in a 2013 report.

We know from past experience that farmed animals can lead to serious zoonotic diseases (those transmitted from animals to humans). Just think back to 2009, when the H1N1 swine flu circulated in pig farms in North America, then jumped to humans. That novel influenza quickly became a global pandemic, killing hundreds of thousands of people.

To be clear, scientists believe the novel coronavirus originated in wild bats, not factory farms. But it has awakened us all to the crushing effect a pandemic can have on our lives. Now that we’ve come face to face with this reality, the question is: Do we have the political and cultural will to do something major — changing the way we eat — to sharply decrease the likelihood of the next pandemic?

What we talk about when we talk about pandemics

When we talk about the risk of pandemics, we’re actually talking about two different types of outbreaks. The first is a viral pandemic; examples include the 1918 influenza pandemic and Covid-19. The second is a bacterial pandemic; the prime example is the bubonic plague, the “Black Death” that wracked Europe in the Middle Ages.

Factory farming presents a risk in both these categories.

Sonia Shah, author of the 2017 book Pandemic, worries about viruses and bacteria alike. “When I was writing my book, I asked my sources what keeps them awake at night. They usually had two answers: virulent avian influenza and highly drug-resistant forms of bacterial pathogens,” she told me. “Both those things are driven by the crowding in factory farms. These are ticking time bombs.”

Let’s focus on avian influenza first. Bird flu is caused by viruses and it’s a massive risk coming out of factory farms (as is swine flu). That’s both because the birds in these farms are squeezed together by the thousands in close proximity and because they’re bred to be almost identical genetically. That’s a recipe for a highly virulent virus to emerge, spread, and kill rapidly.

“Factory farms are the best way to select for the most dangerous pathogens possible,” said Rob Wallace, an evolutionary biologist at the Agroecology and Rural Economics Research Corps in St. Paul, Minnesota. To explain why, he offered a crash course in zoonotic transmission, from the point of view of the pathogen.

“If you’re a pathogen in a host,” Wallace said, “you don’t want to kill your host too fast before you can get into the next host — otherwise you’re cutting off your own line of transmission. So there’s a cap on how much of a badass you can be. The faster you replicate, the more likely you end up killing your host before the next host can come along.”

If you’re deep in the wilderness or on a small farm, you (the pathogen) are not going to regularly come across hosts, so you’ve got to keep your virulence, or harm inflicted on the host, pretty low so that you don’t run out of hosts. “But if you get into a barn with 15,000 turkeys or 250,000 layer chickens, you can just burn right through,” Wallace said. “There’s no cap on your being a badass.”

This is part of why factory farms are a bigger risk for zoonotic outbreaks than the natural world or small farms.

The biologist added that because we’re increasingly trading poultry and livestock across international borders, we’re ramping up the danger even more. Strains that were previously isolated from each other on opposite sides of the world can now recombine.

“Take influenza,” Wallace said. “It has a segmented genome, so it trades its genomic parts like card players on a Saturday night. Usually, most hands are not too terrible, but some hands come out much more dangerous. An increase in the rate of recombination means an explosion in terms of the diversity of pathogens that are evolving.”

The world has already seen a really frightening example of this. Between 1997 and 2006, highly pathogenic strains of H5N1 bird flu were linked to poultry farms in China.

“Our entire understanding of how bad a pandemic could potentially be changed in 1997 with the emergence of the H5N1 avian influenza virus. All of a sudden, there was a flu virus that was killing over half the people it infected,” Greger said.

When people became infected with H5N1, it had a 60 percent mortality rate. For comparison, experts estimate that Covid-19’s mortality rate is probably somewhere in the neighborhood of 1 percent to 3 percent, though these estimates continue to evolve and vary widely by country and by age. (If you’re wondering why H5N1 didn’t become as big a deal as Covid-19, it’s because it mostly infected poultry rather than people; it wasn’t as good at infecting humans as the coronavirus unfortunately is.)

“These new bird flu viruses have been tied to the industrialization — the ‘Tysonization’ — of our poultry production,” Greger said, citing evidence that exporting the factory farming model to Asia led to an unprecedented explosion of viruses infecting birds and people starting in the 1990s.

It’s not only birds we need to worry about. Remember that pigs are also highly effective carriers of viruses. A decade before the swine flu struck in 2009, the Nipah virus emerged in Malaysian pig farms. It caused encephalitis (inflammation of the brain) in hundreds of people, killing about 40 percent of the patients who were hospitalized with serious neurological disease.

Factory farming and the urgent problem of antibiotic resistance

The other pandemic risk associated with factory farms has to do with “highly drug-resistant forms of bacterial pathogens,” as Shah put it — that is, antibiotic resistance.

When a new antibiotic is introduced, it can have great, even life-saving results — for a while. But as we start to use and overuse antibiotics in the treatment of humans, crops, and animals, the bacteria evolve, with those that have a mutation to survive the antibiotic becoming more dominant. Gradually, the antibiotic becomes less effective, and we’re left with a disease that we can no longer treat.

 Brendan Smialowski/AFP via Getty Images

The CDC warned in a major report last year that the post-antibiotic era is already here: We’re living in a time when our antibiotics are becoming useless and drug-resistant bugs, like C. difficile and N. gonorrhoeae, can all too easily decimate our health. Every 15 minutes, one person in the US dies because of an infection that antibiotics can no longer treat effectively.

Yet we continue to dole out too many antibiotics, driving the resistance. Animal farmers use antibiotics copiously on livestock and poultry, sometimes to compensate for poor industrial farming conditions.

“With more spontaneous mutations,” he explained, “the odds increase that one of those mutations will provide resistance to the antibiotic that’s present in the environment.” Those resistant bacteria could become strains that spread all over the world. “That’s the biggest human health risk of factory farms.”

In fact, factory farming presents us with a double bacterial risk. Say a bacterial outbreak emerges among chickens. The poultry can pass that bacteria on to us humans, causing serious infection. We’d normally then want to use antibiotics to treat that infection, but precisely because we’ve already overused antibiotics on our farmed animals, the bacteria may be resistant to the antibiotic. If the infection happens to be one that transmits well between people, we can end up with an untreatable bacterial pandemic.

When asked how he’d compare the pandemic risks posed by factory farms with those posed by China’s wet markets carrying live animals, Lawrence said, “With factory farming, the opportunity to start a viral pandemic may be less, but the opportunity for acquiring an antibiotic-resistant bacterial infection is greater.”

Factory farms also put their workers’ health at risk — including from coronavirus

Another distressing reality of factory farming is the way it tends to treat not only animals but also human workers as widgets in a large machine.

The mistreatment of laborers was a problem long before Covid-19, but the current pandemic has thrown the problem into especially sharp relief. We’re seeing a jump in the number of coronavirus cases among workers at meat plants in the US. Hundreds of people have tested positive at Cargill and Smithfield plants, in states from Pennsylvania to South Dakota. A few have died.

NPR reported that in one case, a city mayor had to actually force Smithfield to close a plant: “The count of positive coronavirus tests among employees at the Sioux Falls plant reached 350. It represented almost 10 percent of all workers at the plant, and 40 percent of all Covid-19 cases in South Dakota.”

 Stephen Groves/AP

Laborers in meat plants are typically stationed very close together along processing lines, which makes social distancing all but impossible. Some workers have staged walkouts over the working conditions.

“The companies need them to be present, but Covid-19 is killing them. And it’s obvious why: They have to stand shoulder-to-shoulder with their coworkers while the rest of us are six feet apart,” said Leah Garcés, the president of Mercy for Animals.

Knowing that the country’s meat is being produced on the backs of laborers who are mistreated, we’ve got to ask: Is it really worth it? For Garcés, the answer is clear. “It’s a ridiculous sacrifice to make for a chicken,” she said.

How can we build a better food system post-coronavirus?

In the US, where meat has become entwined with national identity and the average citizen consumes more than 200 pounds of meat a year, most people are probably not going to give up meat entirely. So it’s worth asking: Is there a way to do livestock farming that diminishes the threat of zoonotic disease? And perhaps, in the process, also diminishes other problems with industrialized farming, like the impact on climate change and cruelty to animals?

The answer is yes. We can absolutely have a meat production system that is better for human health, the climate, and animal welfare — if we’re willing to abandon factory farming.

“The de-intensification of the livestock industry would go a long way toward reducing pandemic risk,” Greger said. “I mean decreasing long-distance live animal transport, moving toward a carcass-only trade, and having smaller and less-crowded farms. Basically, the animals could use a little social distancing, too.”

Greger said we should abolish confinement practices like gestation crates, where pigs are kept in spaces so small they can’t even turn around. “Even measures as simple as providing straw beddings for pigs can cut down on swine flu transmission rates,” he noted, “because they don’t have the immunosuppressant stress of living on bare concrete their whole lives.”

We also need to reintroduce more biodiversity into our farms. Raising animals that are slightly different from each other genetically (rather than selecting for specific genes) will build in immunological firebreaks to help prevent the spread of infectious diseases, Wallace said, adding, “On a very practical level, I would farm completely the opposite of how they’re doing it now.”

By “they,” he means factory farms. There are plenty of farmers who already prefer other methods, like regenerative agriculture, but who may lack the support they need to execute them because agribusiness has a lock-hold on many rural communities.

“There’s a lot of farmers who completely understand how the system works and object to it but just can’t get off the treadmill,” Wallace said. He suspects the pandemic is giving the issue new salience.

It may also shift mindsets around existing plans to stop factory farming, like the legislation proposed by Sen. Cory Booker (D-NJ) to impose a moratorium on the US’s biggest factory farms and phase them out altogether by 2040. In March, as the Covid-19 pandemic gained traction, the conservative magazine National Review carried a piece arguing that “if you reflect on this issue with an open mind, you’ll agree that ending factory farms is a good idea — even if Cory Booker thinks that it is.”

Moving away from industrialized farming can reduce the likelihood of a zoonotic outbreak, but to really remove the threat, Greger said we should be accelerating the movement toward plant-based meat, milk, and egg products.

Americans were already getting excited about plant-based products before the coronavirus came along, and there’s reason to think the pandemic will drive even more interest, both because the traditional meat supply chain is now under some strain and because of a growing awareness that factory farming is a pandemic risk.

Impossible Foods announced on April 16 that it’s expanding sales of its meatless burgers to 750 more grocery stores in the US. “We’ve always planned on a dramatic surge in retail for 2020 — but with more and more Americans eating at home, we’ve received requests from retailers and consumers alike,” said the company’s president Dennis Woodside in an emailed statement. “Our existing retail partners have achieved record sales of Impossible Burger in recent weeks.”

From Garcés’s perspective, increased public awareness of the link between factory farms and pandemics is a silver lining to the horrible Covid-19 pandemic. “In my whole career, I’m not sure we’ve had a better chance than this to have the eyes of the nation and the world on the way we’re using animals in our food system and the risk that puts to us as a species,” she said.

“We’ve been ringing the alarm bells for a long time. My deep hope is that now people will make the connection — factory farming is a catastrophic risk to our species — and that this permanently changes our behavior in the long term.”