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Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
1
Coronavirus ping pong between pigs and humans:
is an infection reverting back from infected pigs conceivable?
The Corona Triangle Part II: Technical Report
Immo Fiebrig • Larissa Bombardi • Pablo Nepomuceno
Introduction
Within the last three months, the international press has reported several cases of
slaughterhouse workers infected with COVID-19. According to the news, many of these
slaughterhouses seem to be some sort of super-spreading hot spot.
Three countries - the United States, Germany and Brazil - drew the attention of the
authors, because of their own nationalities and/or because of the representation that
these countries have in the world’s production and export of pork. These countries will
therefore be the focus of this report.
In terms of the ranking in world pig production
1
, China ranks first, followed by the United
States and the European Union with Brazil coming fourth. Amongst EU countries,
Germany ranks first and slaughters 23% of the EU total of pigs
2
. In these three countries
of focus, there has been a considerable amount of complaint involving cases of
slaughterhouse workers in precarious working conditions who have contracted the
disease.
In Germany, for example, the case of the Tönnies slaughterhouse near Güthersloh in
North Rhine Westphalia, became well known. With more than 650 persons diagnosed
with COVID-19 by 17 June 2020, a new outbreak hotspot was reported, and caused
protests amongst employees
3
. By 22 June 2020, more than 1,500 cases were confirmed
positive out of 6,650 persons tested
4
.
In Brazil, the Public Ministry of Labor investigated 206 complaints involving
contamination by COVID-19 of slaughterhouse workers up to 1 July 2020
5
/
6
. This type of
1
https://www.statista.com/statistics/263964/number-of-pigs-in-selected-countries/
2
https://ec.europa.eu/eurostat/web/products-eurostat-news/-/DDN-20170919-1
3
https://www.spiegel.de/wirtschaft/unternehmen/coronavirus-bei-fleischfabrik-toennies-nicht-fuer-die-
pandemie-gebaut-a-be17ffc1-b4e3-4c16-aaa6-
65d03344c475?sara_ecid=soci_upd_KsBF0AFjflf0DZCxpPYDCQgO1dEMph
4
https://www.zeit.de/wirtschaft/unternehmen/2020-06/toennies-corona-ausbruch-guetersloh-lockdown-
armin-laschet
5
https://g1.globo.com/economia/agronegocios/noticia/2020/07/06/mpt-apura-206-denuncias-e-tem-
114-inqueritos-abertos-por-casos-de-covid-19-entre-funcionarios-de-frigorificos.ghtml
6
https://content.govdelivery.com/attachments/MIEOG/2020/07/09/file_attachments/1492329/EO%2020
20-145%20Emerg%20order%20-%20Workplace%20safeguards%20-%20re-issue.pdf
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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contamination of workers and, obviously, of their family members too, has even been
interpreted as one of the vectors of the pandemic’s interiorisation in the country
7
.
In the United States, the Michigan state governor issued a security order requiring
slaughterhouses to adopt a protection protocol for their employees
8
. The governor, in
issuing the document, stated that slaughterhouses had proved to be an entry point for
COVID-19 infections in other states
9
.
In our previous discussion article
10
, we elaborated the hypothesis - not yet proven - that
COVID-19 infections may occur not only through transmission from person to person, or
by viruses dispersed by human saliva particles and/or present in faeces, but also through
infected pigs. At the end, we posed the questions: “Would pigs contract COVID-19, carry
the virus and in turn infect us?” and, “Could we, if infected with SARS-CoV-2, pass on the
virus to pigs?”
There is, as yet, no conclusive answer to these questions - it would require extensive
animal testing and interdisciplinary studies on the ground. However, in the previous
discussion article, we could show a spatial correlation between areas of intensive pig
farming on the one hand and on the other hand, overlapping areas with a high
population rate infected with COVID-19 in spite of low human population density. We
found this salient spatial correlation using the example of the state of Santa Catarina, in
southern Brazil, which is responsible for more than 60% of pork production in the
country. In this current report, we have expanded our analysis of spatial correlation to
the United States, Germany and the entire southern region of Brazil.
Meat industry: What is involved in mass pig husbandry and slaughtering?
Meat industries worldwide, and particularly those in the three countries analysed here,
have been denounced as amplifying hotspots of COVID-19 infections. Before we get to
COVID-19 infections however, we would like to discuss three basic questions of current
mass animal husbandry, particularly in pork meat production.
1. How are these animals fed? Feed is basically produced from grains such as soybeans
and corn. For every kilogram of pork produced, three kilograms of cereals are needed
11
;
these cereals are mostly transgenic, produced largely in Latin America. The resulting
7
https://g1.globo.com/bemestar/coronavirus/noticia/2020/07/02/coronavirus-cresce-mais-rapido-no-
centro-oeste-que-na-media-do-pais.ghtml
8
https://content.govdelivery.com/attachments/MIEOG/2020/07/09/file_attachments/1492329/
EO%202020-145%20Emerg%20order%20-%20Workplace%20safeguards%20-%20re-issue.pdf
9
https://www.msn.com/en-us/finance/companies/whitmer-signs-order-outlining-safety-guidelines-for-
meat-processing-plants/ar-BB16y1XU
10
https://www.researchgate.net/publication/341525356_Hypothesising_on_the_emergence_of_SARS-
CoV-2_through_bats_Its_relation_to_intensive_pig-factory_farming_and_the_agro-industrial_complex
11
NEGRÃO, S. L. Uma análise do ciclo de produção agroindustrial de suínos e aves, à luz da ética global. Tese.
Programa Interdisciplinar de Ciências Humanas. UFSC. Florianópolis, Brasil, 2008.
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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intensive grain production in Brazil involves serious environmental and social problems:
(1) deforestation of the Amazon rainforest, (2) the intensive use of pesticides in feed
production, and (3) an impact on the country's food security due to the reduction of
areas destined to direct crop production for humans. To give the reader an idea of the
extent of soybean production in Brazil today, the area occupied with soybean cultivation
is equivalent to the entire territory of Germany (Map 1) accompanied by a devastating
effect on deforestation (Map 2).
Map 1: Comparison of the eucalyptus,
sugar cane and soybean areas in Brazil
with the territory of Germany
Map 2: Advance of deforestation and
pesticide use in the Amazon rainforest
2. How are these animals raised? The conditions of husbandry, particularly for chickens
and pigs, are rather inappropriate to the species: there is no space for them to move,
they do not have access to the soil nor to any sunlight. As such, animals feed, defecate
and sleep practically in the same place. To avoid the spread of disease and the
exacerbation of disease symptoms, it is quite common to include antibiotics and other
drugs into their diets
12
.
12
https://www.researchgate.net/publication/341525356_Hypothesising_on_the_emergence_of_SARS-
CoV-2_through_bats_Its_relation_to_intensive_pig-factory_farming_and_the_agro-industrial_complex
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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3. How are these animals slaughtered? The slaughtering of these animals and the work
in the slaughterhouses causes both animals and humans a lot of distress. In all three of
the countries under discussion here, complaints from workers subjected to poor working
conditions grow daily
13
: such complaints include the agglomeration of workers in their
work environment, degrading housing conditions, long working hours, very low wages
and lack of overtime pay. In addition, the majority of workers are migrant labourers: in
the case of the US, these are mostly Latin American migrants
14
and, in the case of
Germany, migrants from Eastern Europe, especially from Romania
15
.
These precarious working conditions, combined with despicable animal husbandry, is
most probably a root cause of the spread of infection in these regions and, often, of new
outbreaks, as was the case in Germany.
In the previous article, we already discussed the hypothesis that such animals – pigs –
may themselves be vectors of this infection. Pigs have numerous similarities with
humans, ranging from the gastro-intestinal system to genetic ones. The immuno-
depressed condition in which these animals live, makes them a great vessel for the
development of infections (swine fever, African fever, etc.) thus also potentially
becoming a ‘focus’ for viral adaptation and mutation.
Spatial correlation between COVID-19 and pork production
For the three countries in question, the USA, Germany and Brazil, the maps that we
present below indicate a salient spatial correlation between the areas with a large
presence of mass pig husbandry and/or slaughterhouses and those in which there is a
high rate of population infected by COVID-19.
USA
It can be noted in Map 3 that the highest density of pigs in the United States has a fairly
clear core in the midwest region, encompassing the states of Minnesota, Iowa (centre of
this pig-producing region), Nebraska, Illinois, Missouri, Indiana and Ohio. There is also an
important concentration of pig farming in the states of Pennsylvania and North Carolina.
13
https://g1.globo.com/economia/agronegocios/noticia/2020/07/06/mpt-apura-206-denuncias-e-tem-
114-inqueritos-abertos-por-casos-de-covid-19-entre-funcionarios-de-frigorificos.ghtml
14
https://www.reuters.com/article/us-health-coronavirus-usa-meat/confirmed-coronavirus-cases-surge-
in-reopened-jbs-colorado-beef-plant-worker-dies-union-idUSKBN22C3VR
15
https://www.spiegel.de/wirtschaft/unternehmen/deutsche-fleischfabriken-in-der-corona-krise-
schlachtbank-europas-a-bc67c942-27ce-4668-8908-
ecde4af86619?sara_ecid=soci_upd_KsBF0AFjflf0DZCxpPYDCQgO1dEMph
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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Map 3: USA and pig farming - average number of hogs and pigs per 100
acres of county farmlands
On Map 4 presented below, we have used the previous map as a basis and overlaid the
data of the COVID-19-infected population rate up to 26 June 2020.
Map 4: USA - overlay of total of COVID-19 infections until 26/06/2020
on pig farming densities
One can also appreciate that the states located in the east and southeast regions are the
ones that also stand out most in relation to high rates of infected population, which, in a
way, is obvious and to be expected due to the high demographic density in these areas,
since the infection is known to spread through interpersonal contact.
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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Map 5: USA - demographic density
It can be noted by comparing maps 4 and 5 that most areas with high population rates
of COVID-19 correspond to those with high demographic density and/or are contiguous
to them, notably, in the northeast and southeast portions of the country. Interestingly,
however, there is another hotspot with high rates of COVID-19 which corresponds
exactly to areas with intensive pig rearing.
We point out that the states of the midwest region, and more importantly, the areas
(municipalities) of these states with intense pig production are also the areas in which
there are high rates of confirmed COVID-19 cases.
Besides that, as we can conversely appreciate on Map 6 below, those areas in the US
with the highest demographic density are not the same areas with the highest number
of pigs.
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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Map 6: USA - demographic density and pig density
Note that in the midwest region, which concentrates intensive pig production, the
population density is not high. And yet, there is a high rate of population infected by
COVID-19, as shown in Map 4.
After selecting the municipalities with more than 500 cases of people infected with
COVID-19 per 100,000 inhabitants and also those counties with more than 10 pigs per
100 agricultural acres, the corresponding synthesis mapping (Map 7) shows a notable
convergence.
Map 7: USA - the synthesis mapping joins areas with high infection
rates and high pig density, highlighting the affected municipalities in red
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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Brazil
Map 8: Brazil - pig farming
Map 9: Brazil - southern region, pig farming and
COVID-19 infections
With regard to Brazil, we observe an analogous situation. More than 70% of its pig
production is located in the southern states. We chose to zoom in on this region and
focus our analysis directly on it.
As in the United States, in Brazil, the spatial correlation can be noted between areas
with pig farming and those with high rates of population infected by COVID-19. And as in
the United States, the coastal region of the country has higher population density, thus
the highest rates of infected population were to be expected. However, in the western
portion of the Brazilian states that make up the southern region - notably northwest of
Rio Grande do Sul, west of Santa Catarina and west of Paraná - this spatial convergence
between a large density of pigs and a high rate of infected population is salient.
By synthesising these two pieces of information (municipalities with the highest rates of
population infected by COVID-19 and those with the highest densities of pigs per
hectare), we obtain Map 10 below.
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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Map 10: Southern region - synthesis map with
relevant municipalities highlighted in red
Map 10 summarises the information displayed on the previous Map 9 with noticeable
spatial correlation between pig breeding and the dissemination of COVID-19.
Germany
The concentration of pig farming and slaughterhouses in Germany takes place in the
northwest portion of the country (Nordrhein-Westfalen, Niedersachsen), as can be
appreciated on Map 11.
For Germany, we obtained data on the location of the slaughterhouses, which allowed
us to add this fundamental element to Map 11 and therefore we can conduct a more
qualified analysis. Essentially, we selected from around 3,800 enterprises with a
slaughtering authorisation and removed all those that were assumed to be too small to
be relevant, that is family farms, local butchers, non-chain hotels and any enterprise that
was not a limited company (GmbH) but a sole trader enterprise. In case of doubt, the
website of each enterprise was consulted to judge whether or not it was a small family
firm, with the result that fewer than 100 companies were left (16 for Nordrhein-
Westfalen alone and 66 for the rest of Germany).
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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Map 11: Germany - pig farming and slaughterhouses
Unlike in the US and Brazil where the municipalities with the highest pig production are
not those with high population density, in Germany, there is a convergence between the
areas with high concentration of pork husbandry and/or slaughterhouses and areas with
higher population density.
Thus, in order to verify whether or not there is also a correlation between the spread of
COVID-19 amongst humans and pig farming activities, we chose to set a time frame,
mapping the data of the infected population rate only in the period between 14 May
2020 and 17 June 2020, that corresponds to the emergence of a second focal outbreak
within a general decrease of COVID-19 infections.
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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In addition, in this case we chose to carry out a statistical exercise that would give us the
certainty that we were dealing indeed with a second focal outbreak: we identified the
rate of increase in the number of cases in this period for the whole of Germany and from
there, we defined the average of this rate within the 14 May to 17 June timeframe. We
then selected to represent spatially only those municipalities that presented a value
higher than the calculated average rate of increase. The results are shown in Maps 12
and 13.
Map 12: Municipalities (Landkreise) that have
presented a value of COVID-19 higher than the
calculated average rate of increase
Map 13: Municipalities (Landkreise) that have
presented a value of COVID-19 higher than the
calculated average rate of increase and where
the main slaughterhouses and/or the higher
pig density (checkered areas) are located
On these maps, it can be noted that there is a salient overlap between the increase in
cases of COVID-19 infection and the presence of pig and/or slaughterhouses. We also
chose to highlight the municipalities that, in addition to having high rates of infection,
are adjacent to those in which there are slaughterhouses and/or intensive pig rearing,
because we take into account the factor of displacement of workers between the
municipality of residence and the municipality of work.
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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Discussion
For the three countries, the population rate infected by COVID-19 was used, that is the
percentage of the infected population. This means that regardless of whether a
municipality has 100,000 or one million inhabitants, it is possible to establish a
comparison between them regarding infections. We are showing through mapping of
the three countries that the regions with high densities of pig husbandry and/or
slaughterhouses overlap with high rates of people infected with COVID-19.
Although the major axes of contamination in the USA and Brazil are those in which there
is greater population density (east coast of these two countries), it is notable that the
second major focus is on the areas in which there is a prevalence of intensive pig
farming and the so-called meat industry.
The methodology used for the case of Germany allowed us to sharpen the mapping
correlation between these elements, since only the areas where there was an increase
in the number of cases of infected people were focused on and it is important to note
that the increase of COVID-19 occurred after the pandemic situation was apparently
‘controlled’. However, the maps cannot prove causality - they only indicate a problem as
a result of the apparent spatial correlation.
In Brazil, factors such as lack of sewage collection and treatment explain why there are
high rates of infection in the northern regions, especially in the northeast region, yet in
the southern region of Brazil, the one with the highest HDI (Human Development Index)
rates, this large number of infected people is not to be expected. However, the total
spatial overlap between these COVID-19 foci and pork production in the country is quite
striking. The same phenomenon is observed in the United States.
Scandals involving the working conditions in slaughterhouses in the three countries
mapped in this report have filled the pages of newspapers around the world in recent
weeks. Slaughterhouse employees have become vectors of pandemic expansion
whether in Germany, the USA or Brazil. The meat industry may have become an
important vector of COVID-19 infections, whether by the inhumane way in which the
production process is carried out for workers in this sector or by way of adverse animal
husbandry standards.
It is noted, therefore, that precariousness and socio-environmental impacts prevail
throughout this production chain: from the production of the grains that feed these
animals (transgenic and with a high load of pesticides), through the industrialised and
technologised form of this animal husbandry model and finally to the degradation of
human labour.
Technical Report: Fiebrig/Bombardi/Nepomuceno – 3 August 2020
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Conclusions
To us, these mappings seem sufficient to raise concern about the meat manufacture
chain from feed production, the conditions of rearing animals and the working
conditions in the slaughterhouses. Further studies and monitoring of the possible risk of
transmission of SARS-CoV-2 to pigs under intensive animal husbandry and back to
humans, possibly from pig faeces, should be undertaken in order to safeguard human
health globally.
In summary, by means of human geography mappings as the method chosen here, we
are observing a salient overlap between COVID-19 in humans and the pork industry in
three major corona-affected countries. It is a ‘view through our macroscope’ that
indicates a correlation - but is unable to prove causality. Instead, it would in any case be
the duty and responsibility of virologists, epidemiologists or veterinarians to investigate
causality by ‘taking a look through their microscope’ - to assess possible risks from
industrial meat production. •
________________________________________________________________________
Author affiliations
Dr. Immo Fiebrig ()
Honorary Associate Professor
NCMH, School of Biosciences, University of Nottingham, Sutton Bonington Campus,
LE12 5RD Sutton Bonington, United Kingdom; e-mail: immo.fiebrig@immofiebrig.de
Dr. Larissa Bombardi
Professor at Department of Geography,
University of São Paulo, Av Professor Lineu Prestes, 338
Cidade Universitária, São Paulo, SP-05508-000, Brazil; e-mail: larissab@usp.br
Dr. Pablo Luiz Maia Nepomuceno
Department of Geography, University of São Paulo, Av Professor Lineu Prestes, 338
Cidade Universitária, S. Paulo, SP-05508-000, Brazil; e-mail: pablo.nepomuceno@usp.br
Release date: 3 August 2020; Nottingham/São Paulo; ResearchGate
© The Authors