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The problem

As COVID-19 has shown all too clearly, diseases can jump to humans from other animals. In fact, according to the US Centers for Disease Control and Prevention, three out of every four new or emerging infectious diseases in people come from animals.1

So, how we treat wild and farmed animals isn't just critically important to their wellbeing. It is crucial to human health.

Breeding grounds for disease

Factory farming already plays a devastating part in 'hidden' human pandemics. It helps to fuel poor diets that contribute to coronary heart disease, diabetes and some cancers.2 It is also a major cause of air pollution: if global agricultural emissions were halved, up to 250,000 air pollution-related deaths could be prevented, every year.3

Crucially, there is also a wealth of evidence that the stressful, crowded conditions on factory farms help drive the emergence and spread of dangerous, infectious diseases.

[There is] strong evidence that the way meat is produced, not only in China, contributed to COVID-19.

− Virginijus Sinkevicius, EU Environment Commissioner4

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How factory farming could lead to the next pandemic

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2. How factory farming could lead to the next pandemic
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Viruses: the clock is ticking

Viruses from both pigs and birds can infect people, and studies suggest that crowding animals together in factory farms makes diseases more likely to develop and spread.5,6

The European Food Safety Agency says that the stress animals suffer in intensive farms may increase their risk of contracting disease.7 The Scientific task force on Avian Influenza and Wild Birds states that outbreaks of highly pathogenic − dangerous − bird flu are typically associated with intensive poultry farming.8 And, because pigs can be infected by avian, swine and human influenza, intensive pig farms may be powerful 'mixing pots' for new, deadly viruses.

Indeed, we are not dealing in hypotheticals: Before COVID-19, the last global pandemic was in 2009. Then, a swine flu emerged from multiple viral gene 'reassortment events' in farmed pigs9, and killed between 150,000 and 575,000 people10. La Gloria, the Mexican town widely identified as the pandemic's source11, is just five miles from a major concentration of industrial pig farms.

It has happened before, and it could happen again. Factory farms are a ticking timebomb for the next global pandemic.

COVID-19 is a wake-up call... If we just carry on with business as usual, that will lead to the end of our species' tenure on planet Earth.

− Jane Goodall, PhD, DBE, Founder − the Jane Goodall Institute, UN Messenger of Peace and Patron CIWF12

Lame pig alone in factory farm corridor

Bacteria: a pandemic on our plates

Every year, hundreds of millions of people fall sick, and hundreds of thousands die, due to food-borne bacteria13 − and our broken food system is at least partly to blame.

Evidence suggests that fattening cattle in barren feedlots on unnatural, grain-based diets encourages the growth and spread of E.Coli. Up to a quarter of cows in the USA, where feedlots are common, carry E. coli at slaughter. In the UK, where most cows are raised on pasture, this figure is reportedly less than 5%.14

In laying hens, larger flocks increase the level of Salmonella; and several studies have found that caged birds have much higher levels of this bacteria.15 Meanwhile − in another example from the USA − notoriously poor conditions on chicken farms are accompanied by rates of Salmonella infection in chicken meat up to seven times higher than in the UK.16

What is more, antibiotics are overused in factory farms, to prop up systems that would otherwise make animals sick. This contributes to the spread of antibiotic-resistant bacteria.17

A post-antibiotic era − in which common infections and minor injuries can kill − far from being an apocalyptic fantasy, is instead a very real possibility for the 21st century.

− World Health Organization18

Factory farmed chicken with sores squatting in litter

The solution

To end animal cruelty and cut the risk of future pandemics, we need a revolution in our food system. And the solutions are out there19:

  • Modern, progressive types of farming, like agroecology and circular agriculture, can produce food ethically and sustainably, enriching rather than destroying the environment.
  • Reducing meat consumption would protect the world's resources, and allow the remaining farm animals to live healthier, happier lives.
  • Economic models that focus on social and planetary goals − what we, the environment, and animals need and want − can replace models focused on maximising production.
  • taxes can be used to address the 'negative externalities' − or hidden costs − of factory farms, whilst subsidies can be applied to support higher welfare farming and shopping.
  • And savings in healthcare costs could be made through social measures to ensure everyone can afford healthy, humane food.

We must demand that politicians, policy makers, and global institutions act on these opportunities, and use their power as a force for good. We must convince society to fundamentally reassess its relationship with animals and end factory farming.

Take action


  1. Centers for Disease Control and Prevention, 2017. Zoonotic Diseases, viewed 5 August 2020,
  2. Compassion in World Farming, 2020. Is the next pandemic on our plate? (see p.12 for links to multiple primary sources),
  3. Pozzer A et al, 2017. Impact of agricultural emission reductions on fine-particulate matter and public health, Atmos. Chem. Phys., 17, 12813-12826,
  4. Reuters, 2020. EU to step up rules on factory farming, wildlife trading amid pandemic, viewed 7 August 2020,
  5. Otte et al, 2007. Industrial Livestock Production and Global Health Risks
  6. CAST, 2005. Global Risks of Infectious Animal Diseases. Issue Paper 28, February 2005, viewed 7 August 2020
  7. EMA (European Medicines Agency) and EFSA (European Food Safety Authority), 2017. EMA and EFSA Joint Scientific Opinion on measures to reduce the need to use antimicrobial agents in animal husbandry in the European Union, and the resulting impacts on food safety. EFSA Journal 2017;15(1):4666
  8. Scientific Task Force on Avian Influenza and Wild Birds, 2016. Statement on H5H8 Highly Pathogenic Avian Influenza (HPAI) in poultry and wild birds, viewed 7 August 2020
  9. Gibbs, A.J., Armstrong, J.S. and Downie, J.C., 2009, From where did the 2009 'swine origin' influenza A virus (H1N!) emerge?, Virol J 6, 207 (2009).
  10. Centres for Disease Control and Prevention, 2019. 2009 H1N1 Pandemic (H1N1pdm09 virus), viewed 7 August 2020,
  11. Fraser C, Donnelly CA, Cauchemez S, et al, 2009. Pandemic potential of a strain of influenza A (H1N1): early findings. Science. 2009;324(5934):1557-1561. doi:10.1126/science.1176062,
  12. Webinar: Pandemics, Wildlife and Intensive Farming, 2 June 2020, extracted footage viewed 7 August 2020
  13. World Health Organization, 2015. WHO estimates of the global burden of foodborne diseases
  14. Compassion in World Farming and The World Society for the Protection of Animals, 2013, Zoonotic diseases, human health and farm animal welfare (see p.5 for links to multiple primary sources),
  15. Compassion in World Farming and The World Society for the Protection of Animals, 2013, Zoonotic diseases, human health and farm animal welfare (see p.8 for links to multiple primary sources),
  16. Compassion in World Farming and The World Society for the Protection of Animals, 2013, Zoonotic diseases, human health and farm animal welfare (see p.8 for links to multiple primary sources),
  17. Alliance to Save Our Antibiotics, 2015. Antimicrobial resistance − why the irresponsible use of antibiotics in agriculture must stop,
  18. World Health Organization, 2014, Antimicrobial resistance: global report on surveillance
  19. Compassion in World Farming, 2020. Is the next pandemic on our plate

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