An Ugly Truth: Pandemics and the Livestock Trade

Image Credit: Hippopx, CC0 1.0, Image Cropped.

Ever since COVID-19 hit, things have changed for people the world over. Many governments enforced lockdowns on their citizens, certain products are harder to get than before (looking at you toilet paper hoarders), and there has been an enormous and terrible loss of life. A wet market in China is suspected to be the source of the outbreak, but one thing to consider as we move forward is that the risk of another outbreak from other animal markets remains high.

Industrial Farming

Industrial farming is an ugly truth that not many people are truly aware of, and while I think that it is an issue worth discussing, it is not the point of today’s article. I bring it up instead to give a sense of the sheer scale of industrial farming and what it entails. Not only are animals being raised in famously unsanitary conditions, but they are kept in incredibly crowded conditions, with hundreds or even thousands of animals in close contact with one another. This close contact is where the risk of deadly disease comes into play. I’m a disease ecologist, and one of the first things I learned about disease was that the more dense a population, the more likely a disease is to spread (social distancing, anyone?). Animal cruelty and welfare aside, we have a safety issue with the way in which these animals are raised, housed, and traded.

There are close to 8 billion people on this planet, all of whom need to eat. Most people consume some form of animal product as a part of their daily diet. This huge demand for animal products, specifically meat, means that livestock make up close to 60% of the biomass of all animals on Earth. That sounds like a big number (because it is!), but what makes that number even more staggering is that wild animals only make up 4% of the planet’s biomass. To put that into perspective, imagine that for every wild animal you see there are 15 cows being raised to become someone’s meal. Because of this population size, there isn’t enough land mass on Earth to capably raise these cows “free range”, thus factory farming steps in. Limiting large population sizes to a much smaller than normal land area. So not only are livestock kept in conditions that are perfect for an outbreak to occur, but there are so many of them that the probability of a new outbreak happening is much higher than it normally would be.

Disease Outbreaks and Livestock

COVID-19 may have come from a wet market in China, but it is not the first outbreak linked to animal markets and industrial farming. In 2017 a different type of coronavirus (not COVID-19) swept southeast China and killed 25,000 pigs. One year later yet another pig disease spread across China. That disease killed at least 100 million pigs, devastated China’s pork industry, and it continues to spread across Asia today. Despite these examples, the issue of an outbreak via livestock is not exclusive to China. Remember H1N1 (aka swine flu)? I was fortunate enough to avoid contracting it myself when it started in the US in 2009, but swine flu was responsible for the deaths of hundreds of thousands of people the world over after originating at a pig farm in Mexico. Another famous example is Creutzfeld-Jakob disease, more commonly known as mad cow disease. After originating in the United Kingdom in the 1980’s, this disease was responsible for deaths of over 100 people and the culling of millions of cows. It also resulted in bans on the export of British beef and regulations on the cattle industry as a whole.

Disease outbreaks coming from animal farms are nothing new, but why do they happen? Animals on these farms can consume food or water contaminated with a virus transmitted from bird or bat droppings. All it takes is one animal becoming infected for the virus to not only spread throughout the farm, but to also change and mutate as it goes. These mutations are how viruses then jump species, because they become really, really good at invading and taking over cells, causing damage to their hosts. The ability of these viruses to take over cells after jumping species makes them particularly dangerous to humans, as our immune systems aren’t prepared for a completely new virus.

Despite previous outbreaks in the 21st century such as SARs and the previously mentioned H1N1, not enough about the livestock industry has changed to prevent future outbreaks from happening again. Industrial farming provides the perfect recipe for disease that could adversely affect humans: animals are not only kept at high density and transported to different markets globally, but they are also kept in close proximity to other animals and humans. These dangers are not limited to large-scale industrial farms. Small “backyard farms” like those around where I live don’t operate at the scale that the larger factory farms do, but they tend to abut areas containing native wildlife. Any disease that breaks out in a small farm could spread to the wild animals nearby and decimate native populations (or vice versa). Contact with livestock is actually how koalas are thought to have originally contracted chlamydia, a disease that is the second-highest cause of mortality for koalas.


Small farms like this one in rural Georgia don’t have quite the same issues with scale that a factory farm does, but they do run the risk of contact between livestock and native wildlife (Image Credit: JR P, CC BY-NC 2.0)

Next Steps and Take Home Message

Unfortunately, most of the burden to reduce the risk of future outbreaks falls on the shoulders of the livestock industry. Large factory farms need to take steps to improve biosecurity at their facilities. This could be done through screenings to test for diseases and restricting the number of animals kept together. But they can also take steps to limit potential contact between livestock and other organisms, be they wild animals or humans. The sheer number of farms engaged in the livestock industry, and the fact that humans eventually end up eating animal products that come from these farms, mean that they have a responsibility to be better than they have in the past.

It is also possible to help out by taking steps in your own life to limit how much you contribute to industrial farming and the livestock industry. I say this as a former omnivore and meat-lover who recently became vegan, because not only do I find industrial farming needlessly cruel, but it is also unsustainable at its current scale and contributes to ecosystem destruction and climate change. Whether it’s trying out new (and delicious) plant-based alternatives, having a small coop of backyard chickens, or speaking with elected officials about changing current or upcoming agricultural policies, there are a variety of ways to aid in the reduction of large scale factory farming. We at Ecology for the Masses are firm believers that the perfect should not be the enemy of the good, and as such feel that any step taken to improve some issue is worth taking, no matter how small.

Disease can be scary, especially a disease that affects so many people with such deadly consequences. We are all living through a potential turning point in our history, and whether or not we avoid another pandemic will depend on how the livestock industry (and the laws regulating it) respond.


If you want to learn more about the livestock trade and factory farming I encourage you to do your own research and educate yourself on the issues surrounding the animal product industry. As I mentioned above the livestock industry is unsustainable in its current form, but it also entails a large amount of cruel treatment and abuse of the animals themselves. The documentary “Dominion” is freely available on YouTube and offers a non-biased, educational insight into the world of factory farming. Full disclosure: Dominion is incredibly hard to watch and contains lots of graphic and upsetting content, but I think it is important to know where your food comes from.

Adam Hasik is an evolutionary ecologist interested in the ecological and evolutionary dynamics of host-parasite interactions. You can read more about his research and his work for Ecology for the Masses here, see his personal website here, or follow him on Twitter here.

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