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Because 60% of all emerging infectious diseases are zoonoses and because animal farming is one of the main contributors to antibiotic resistance, one of the most effective ways to prevent pandemics seems to reduce animal farming and hunting.


WHO “warned in its 2007 report that infectious diseases are emerging at a rate that has not been seen before. Since the 1970s, about 40 infectious diseases have been discovered, including SARS, MERS, Ebola, chikungunya, avian flu, swine flu and, most recently, Zika.” [1] Could the increase in emerging infectious diseases have to do with the increase an intensification in animal farming? The number of farmed animals almost quadrupled in the last 50 years [2]. The main rise was in poultry birds (483%), which were the leading cause of the H5N1 epidemic in 2003 (455 human deaths) and the H7N9 outbreak in 2013 (616 human deaths)[3]. Farmed sheep and goat populations swelled by 156%, and cows and buffaloes 147% during that time. Cows were responsible for Variant Creutzfeld-Jacob disease (‘mad cow disease’/BSE) which claimed hundreds of human lives.Correlation is not causation, but as Al-Jazeera showed in March 2020, most epidemics had to do with animals (see graph below). A widely-cited article in Nature notes that 60% of all emerging infectious diseases are zoonoses, i.e. either came from wild or farmed animals, or animals can at least transmit them.[4]

Larger version - Source: [3]

‘Species distancing’: No farming and hunting of animals

I propose two measures to reduce epidemics: Not farming and not hunting animals. These measures would block the main routes of transmission from animals to humans[5]. According to CDC[6], these are contact with bodily fluids of animals (most common in farming, hunting and animal product processing), food (think salmonella in eggs, E. coli from contamination with faeces), and bites and waterborne transmission. Only bites and waterborne transmission would not be solved.

Antibiotic resistance

Preventing animal husbandry is also necessary to prevent antibiotic resistance. Yes, not only viruses, but also bacteria can cause pandemics. Take meningitis: “In 1996, the largest meningitis epidemic ever recorded, in terms of the numbers of affected people, occurred in West Africa. An estimated 250,000 people contracted meningitis, and 25,000 people died of the infection.” [7] “Neisseria meningitidis [a bacterium] is the major cause of seasonal meningitis epidemics in the African meningitis belt.” [8]The more animal products humans consume, the more vulnerable they become to antibiotic resistance. In 2017, 26% of all antibiotics were given to livestock in the UK.[9] The percentage in the US is estimated as high as 80% (and in most other countries, antibiotics given to animals are unfortunately not tracked). The “WHO is recommending that farmers and the food industry stop using antibiotics routinely to promote growth and prevent disease in healthy animals.” [10]Might the WHO proposal not be an unnecessary and unrealistic extra step? After all, its implementation would hurt profitability or animal welfare (because farmed animals would fall ill easier unless one gives them more space). Reducing animal farming and transitioning to plant food seems a more painless and safer alternative that also has other benefits for global public health (e.g. cancer from red and processed meat[11]).

Open questions

The following are questions I was unable to answer with a 1-hr Google search. Please provide comments if you have ideas on who could answer the following questions:

  • What diseases were spread by farmed and hunted animals and which are likely in the future?
  • What is more effective, reducing contact with wild animals (“banning bush meat”, closing ‘wet markets’ as widely proposed) or reducing farming?
  • What share are animal-to-human zoonoses in the 60% zoonosis number?
  • What share of human infections with zoonoses occur through bites and waterborne transmission?
  • What level of reduction would be how effective? I suspect that contact reduction and pandemic risk reduction are positively correlated. However, what shape could the following curve have?

Larger version - Source: Own imagination. Risk of pandemic of 1 corresponds to the current (2020) risk of a future pandemic. Restriction in contact with animals is from 0 (no restriction) to 1 (no animal farming and hunting).


[1] https://www.bcm.edu/departments/molecular-virology-and-microbiology/emerging-infections-and-biodefense/emerging-infectious-diseases

[2] Own calculation (see Google sheet) using data from UN FAO 2019. Calculation of the number 2.7%: In 50 years, the number of farmed Poultry Birds, Sheep, Goats, Cattle and Buffaloes grew by a factor of 3.725685523 ≈ (1+0.0266558)^50

[3] https://www.aljazeera.com/indepth/interactive/2020/02/deadly-viral-outbreaks-originated-animals-200205173647803.html

[4] About emerging infectious diseases (EIDs): “EID events are dominated by zoonoses (60.3% of EIDs) “- Jones KE, Patel NG, Levy MA, et al. Global trends in emerging infectious diseases, Nature, 2008, vol. 451 7181(pg. 990-993), online at https://www.nature.com/articles/nature06536

[5] And vice versa, which may also contribute to human pandemics by leaving human viruses and bacteria to mutate in large biomass stocks, stocks that are much larger than the 7bn humans we have (For wild animal biomass and population estimates see Brian Tomasik’s article)

[6] https://www.cdc.gov/onehealth/basics/zoonotic-diseases.html

[7] https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/epidemics-bacterial

[8] https://www.sciencedirect.com/science/article/pii/S1201971216312188

[9] UK One Health Report, 2019, p. 11. Calculation: 26%=281.6/(491.0+281.6)*72% (the latter figure being the share of livestock in all animals)[10] WHO: Stop using antibiotics in healthy animals to prevent the spread of antibiotic resistance[11] WHO: Q&A on the carcinogenicity of the consumption of red meat and processed meat; NHS: Red meat and the risk of bowel cancer





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I haven't looked into this much, but my impression is that mainstream public health experts are worried about overuse of antibiotics in factory farming, and maybe about specific settings like wet markets, but that calls for stopping meat consumption in general are coming from the animal advocacy side more than the public health side. I'd be interested in whether mainstream public health people think reduction in animal consumption is a tractable thing to push for. My guess is that this looks much more worthwhile to work in if you factor in animal welfare, but on public health grounds doesn't seem to be all that tractable compared to other ways to reduce pandemic risk?

From a sociological perspective, a transition to "not hunting and farming animals" would mean big shifts in economics, food culture, etc. Even if governments decided they wanted to do this, it's a much harder step to take than a lot of other steps they could take toward reducing pandemic risk. When you look at the efforts to reduce poaching of certain species it hasn't been easy or fully successful, and moving to preventing all animal consumption would be many times harder.

There is some call in public health for work to reduce risk of zoonoses. This includes training in some LMIC's to improve hygeine and care around animals, and for vaccination of flu in some animal populations.

// On tractability and implementation

Thanks for your thoughts! I agree with everything you say but one thing, but maybe you can explain a bit more so I understand: "Even if governments decided they wanted to do this, it's a much harder step to take than a lot of other steps they could take toward reducing pandemic risk"

Are you referring to specific measures? One much-proposed idea seems to invest in medical systems[1]. However, that costs around 3% of world GDP[2] whereas my measures don't seem to cost much. Readying healthcare systems to nip pandemics in the bud also seems very unlikely to be solved in the next decades in developing and emerging economies, where most pandemics originate.[3]

The developing country origin of pandemics means that my measures might be the next best option if healthcare is too expensive, but it also means that they must be implemented in developing countries if they are to be successful.

My intuition is that any solution will be driven by superpowers such as the US and China, which are able to partially coerce the others. I also suspect that global sentiment towards development assistance is currently so bad that it is easier to convince superpowers to force a meat and game reduction from poor countries than it is to convince superpowers to fund poor countries' healthcare systems. Some states may resist (such as Tadjikistan), but that's a problem for any measure to prevent pandemics.

Another problem is shadow markets. They persist for many products and services that governments have tried to discourage, like drugs and prostitution. However, unlike with those two, there is a clear, safe and cheap substitute for animal products - plant products.

Governments around the world seem quite successful in shutting down entire sectors of their economies right now. Why not animal farming and hunting? Governments have successfully influenced diets systems in the past[4]. They promoted crops from other continents such as potatoes and maize. South Korea promoted a particular form of traditional cuisine with public cooking courses.[5]

We only need to convince governments, i.e. we need a stronger medical case.

[1] "The most cost-effective strategies for increasing pandemic preparedness, especially in resource-constrained settings, consist of investing to strengthen core public health infrastructure, including water and sanitation systems; increasing situational awareness; and rapidly extinguishing sparks that could lead to pandemics." https://www.ncbi.nlm.nih.gov/books/NBK525302/

[2] https://data.worldbank.org/indicator/SH.XPD.CHEX.GD.ZS hows how much is spent on healthcare by government and private individuals. If you compare developed to developing economies, there are gaps of 5-7% of GDP between rich and poor countries (e.g. the Euro area spends 10% of GDP and Sub-Saharan Africa spend 5%). We would have to spend maybe 3% of world GDP if we were to make all public health systems industrial standard. This takes into account that the share of not-pandemic-ready countries is maybe 60% but that it is cheaper to make these countries ready because labour costs are lower. However, it does not account for the cost of building working education systems for doctors and nurses.

[3] This seems partly due to the correlation of developing country status and tropical areas, which in turn correlate with high biomass and therefore many zoonoses (I heard in a news report on German state TV which is usually reliable). It's probably also because developing countries are just so resource-constrained that they're bad at nipping pandemics in the bud (would SARS-Cov-2 be a thing had it emerged from bats in Canada?).

[4] Behavioural Insights Team, 2020. Menu for Change, pp.19-21. https://www.bi.team/wp-content/uploads/2020/03/BIT_Report_A-Menu-for-Change_Webversion_2020.pdf.pdf

[5] Soowon Kim, Soojae Moon, Barry M Popkin, The nutrition transition in South Korea, The American Journal of Clinical Nutrition, Volume 71, Issue 1, January 2000, Pages 44–53, https://doi.org/10.1093/ajcn/71.1.44

"A more plausible explanation is that movements to retain the traditional diet have been strong in South Korea. These movements include mass media campaigns, such as television programs that promote local foods by emphasizing their higher quality and the need to support local farmers (eg, Korean Broadcasting System First station's daily program Six O'clock My Village introduces famous products of South Korean villages and promotes consumption of traditional dishes). South Korea also promoted the concept of “Sin-To-Bul-Yi” (translated directly as “A body and a land are not 2 different things,” meaning that a person should eat foods produced in the land in which he or she was born and is living).

Part of this effort is reflected in a unique training program offered by South Korea's Rural Development Administration. Beginning in the 1980s, the Home Management Division of the Rural Living Science Institute trained thousands of extension workers to provide monthly training sessions on cooking methods of traditional Korean foods such as rice, kimchi (pickled and fermented Chinese cabbage), and fermented soybean foods. These sessions are open to the public in most districts of the country and the program appears to reach a large audience (41)"

"Another problem is shadow markets. They persist for many products and services that governments have tried to discourage, like drugs and prostitution. However, unlike with those two, there is a clear, safe and cheap substitute for animal products - plant products."

There are also substitutes for illegal drugs and prostitution, e.g. legal drugs, and masturbation, respectively. Despite this, there is still a market for illegal drugs and prostitution, though perhaps a smaller one than if those substituted didn't exist. The substitutes are already priced into the market.

We already eat plants, which means we already eat less animal product than if the substitute didn't exist. The substitutes are already priced into the market. You can probably shift demand further by subsidizing the substitutes or taxing the animal products, but this requires political capital or better supply of substitutes, not just pointing to existing substitutes.

I would expect the low-hanging fruit to be things like closing certain types of operations or outlawing certain practices, not ending animal consumption entirely.

This industry wouldn't just vanish costlessly - it would have to be replaced with something else, in terms of livelihoods for people who currently work in that sector, economic reality for low-income people who raise and hunt animals, and food culture. For example, I'm from Virginia where tobacco used to be a major crop and still is to some degree (despite the frowns of public health experts). When the government decided to start discouraging tobacco use, those tobacco farmers had to be transitioned to another livelihood. For example, in 2004 the federal government offered $10 billion in buyouts to encourage tobacco farmers to switch to another crop.

The study you point to on the "nutrition transition in South Korea" includes in its summary "Major dietary changes included a large increase in the consumption of animal food products and a fall in total cereal intake." Providing lessons to people in preparing traditional plant-based foods doesn't mean that's what people will actually do en masse. 

I didn't mean to cite the Korea study as an example of plant-based campaigns. It is not. It's a nationalist and traditionalist campaign but it shows that diet change campaigns such as cooking courses have been (cited as) highly effective; at least the study claims that the government campaigns were a main contributor to the fact that Korea is the least obese country in the OECD.

One would also need to change school curricula with their food pyramid, direct change in public catering, get nutritionists to agree that animal protein has no benefits etc. Most animal/vegan organisations are working on that in some way but aren't hugely successful (vegans are only 1% in most societies) - it is hard to work on the demand side. But if you take away the supply then it might be easier. People choose food mostly because of taste, price and convenience, not much because it contains an animal product.[1]

So if animal products are restricted due to pandemic risk, they're more expensive and market forces will drive them out.

You're right about replacing livelihoods, buyouts / nationalisation programs and reactance from 'luddite' farmers. I think this is actually a more difficult point than changing diets, and something the animal people are ignoring a bit. Interesting with the $10 bn US buyout in 2004. It doesn't seem that much, it's about 0.43% of the federal budget (which was $2.3trn and 19% of GDP in 2004[2]), but the cost might be higher for an animal husbandry buyout.

Anyone, please let me know if you're interested in working on this or have more information:

It seems important to more accurately estimate the economic cost of different pandemic mitigation options, including my 'species distancing'. There are emotional costs, too; economic arguments against Brexit haven't convinced everyone. These apply both to fears of dying from zoonotic disease and fears of having to eat a vegan steak and having to replace one's livelihood. Again, these would be good to quantify. There are also distributional costs; Julia_Wise mentions low-income people who hunt for a living (perhaps even illegally, see bans on pangolin hunts and its role in covid-19, or illegal use of great apes and the potential origin of the HIV virus).

[1] https://www.cam.ac.uk/vegnudge https://europepmc.org/article/pmc/pmc6800350 [2] https://en.m.wikipedia.org/wiki/2004_United_States_federal_budget

Michael Huemer has written on this here: https://fakenous.net/?p=1397

Some good counter-arguments have been raised in the comments.

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