An Open Letter on COVID-19 & Industrial Mink Farms.
We, the undersigned experts in public health, animal welfare, wildlife conservation, animal medicine, and infectious disease, call on the Biden Administration and the Governors of each affected state to immediately implement a prohibition on the breeding of mink on industrial fur farms. This urgent action is necessary to prevent the emergence of dangerous variants of the virus that causes COVID-19, avert spillover events into wild animal populations, protect the efficacy of vaccines, and ensure that mink do not act as enduring reservoirs of the virus. Failure to act on this threat could profoundly hinder our efforts to control the pandemic and eradicate this deadly disease.
Susan Lieberman, Ph.D.Vice President, International Policy
Wildlife Conservation Society
Kirsten Jackson, BSc BVMS, MANZCVS
Joanne Lefebvre Connolly, DVM
Daniel Coombs, Ph.D.Professor and Head, Mathematics Department
University of British Columbia
Ernie Ward, DVM
Debra Teachout, DVM, MVSc
Ian DuncanProfessor Emeritus, Emeritus Chair in Animal Welfare
University of Guelph
Daniela Castillo, DVM
Paul Mozdziak, Ph.D.Professor and Director, Graduate Physiology Program
North Carolina State University
Jan Hajek, MD, FRCPCInfectious Diseases Specialist, Vancouver General Hospital
Clinical Assistant Professor of Medicine, University of British Columbia
Piotr Rzymski, MD, Ph.D.Professor, Department of Environmental Medicine
Poznan University of Medical Sciences
Crystal Heath, DVMCo-Founder
John D. Kriesel, M.D.Infectious Diseases Specialist
Dariusz Halabowski, MScInstitute of Biology
University of Silesia
Isabella Rauch, Ph.D.Department of Molecular Microbiology & Immunology
Oregon Health & Science University
Jeffrey Laifer, DVM
Kaitlyn Benally, DVM CandidateUniversity of Arizona
Barbara Poniedziałek, Ph.D.Poznan University of Medical Sciences
Department of Biology and Environmental Protection
Jim Keen, DVM, Ph.D.Public health veterinarian
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COVID-19 & Industrial Mink Farms
Bidirectional zoonotic transmission and the “spillback” effect
Like many infectious diseases, SARS-CoV-2, the virus that causes COVID-19, is a zoonotic pathogen, meaning it originated as an endemic disease in nonhuman animals before jumping the species barrier and infecting humans, a process known as the “spillover effect.”1 While most pathogens that spillover to humans fail to result in widespread secondary transmission, zoonotic pathogens that are capable of such transmission can result in severe pandemics, because humans represent a large social population of hosts who have not previously encountered the novel virus and are thus immunologically naïve. SARS-CoV-2 is one such case.2
A growing body of research also reveals that humans infected with SARS-CoV-2 can, in some cases, transmit the virus to nonhuman populations, a process sometimes called the “spillback effect,” or “reverse zoonoses.” Domesticated animals who are intensively confined in laboratories or on agricultural operations are particularly susceptible to reverse zoonotic outbreaks, and these environments often have various biosecurity measures to prevent such incidents. SARS-CoV-2 infections have been identified in a handful of nonhuman species, but mink appear to be particularly susceptible to contracting the virus, and to date, mink are the only species known to readily transmit the virus both to and from humans, a process known as bidirectional zoonoses.3
Behind closed doors, the fur farming industry has itself admitted the severity of the crisis. At the September 28, 2020 annual convention of Fur Commission USA, Dr. John Easley, DVM, Director of Research, stated:
[Researchers are] extremely confident that they’ve been able to demonstrate that [COVID-19] was brought on to farms by humans, the virus changed in the mink, and that changed virus was then transmitted back to people, and the people that got infected, transmitted that virus to other people. This is new information that is out now, so that is extremely important to the industry. It shows that mink can potentially be a reservoir for the virus, for the human population.4
The Netherlands’ Takes Decisive Action to Curb the Threat
Following unusual widespread mortality events on two different mink farms in the Netherlands, SARS-CoV-2 infections were first identified in mink by researchers in April 20205. It is believed that in both cases, infected workers on these operations first gave the virus to the mink, who then spread it to one another. The researchers also found evidence that seven feral cats who lived near these two mink farms had also been recently infected. Mink appear to transmit SARS-CoV-2 much the same way humans do, via respiratory droplets, and when one mink is infected, it can quickly and easily spread throughout the whole farm. Mink on fur farms are typically confined in tiny shoebox-sized wire cages, in close quarters with one another, with one shed containing hundreds, if not thousands, of mink. There is no social distancing for these cruelly confined animals.6
Dutch officials immediately recognized the gravity of the situation, and ordered an exclusion zone surrounding these two farms. All roads within 400 meters of each form were ordered closed to all pedestrians and cyclists.7 Researchers were concerned that SARS-CoV-2 viral particles were found in the fecal dust on these operations, and that wind or other mechanical vectors could spread the virus into the vicinity surrounding the farms. Indeed, Danish researchers did confirm through laboratory tests that the SARS- CoV-2 virus was present “in air samples collected close to the mink, on mink fur, on flies, on the foot of a seagull, and in gutter water” near mink farms.8
Unfortunately, the problem continued to worsen. By August, more than one-third of all Dutch mink farms had active COVID-19 outbreaks. Worse, there was clear evidence that the mink were transmitting the virus back to humans. One team of Dutch researchers found that 68% of “farm workers and/or relatives or contacts would later become or had been infected with SARS-CoV-2, indicating that contact with SARS- CoV-2–infected mink is a risk factor for contracting COVID-19.” This rate of infection – 68% – is considerably higher than those found in meatpacking plants (9.1%)9 and frontline healthcare workers (3.9%).10
Dutch public health officials soon concluded that “[i]t is undesirable that the virus continues to circulate on mink farms as there is a risk that, in the long term, this will lead to infections – via employees – of people outside the mink farm.”11 The Dutch government ordered the industry be shuttered at the end of the next pelting season, which begins in November 2020 but can run as late as March 2021. Prior to this order, the Netherlands had been the world’s fourth largest mink producing country, with 130 active farms and annual exports valued at $101 million.12
Danish Mink Farms Give Rise to COVID-19 Variants
Bidirectional zoonotic viral transmission is particularly dangerous.13,14 Each time a virus enters a host and uses its cellular machinery to replicate copies of itself, there is a potential for viral mutation, or changing of the genetic code of the virus. More replication leads to more mutations. When a virus finds a new species to infect, this organism’s immune system also acts upon the virus in unique ways, further increasing the chances of a virus accumulating changes and becoming a “variant” strain. Variants are a serious concern in controlling a pandemic because variants can be more contagious, more lethal, or more evasive of protective vaccines. Researchers have already positively identified variants of the COVID-19 virus that arose on mink farms in Denmark and later spread into the wider community.
Prior to the COVID-19 pandemic, the Danish fur industry was the largest producer of mink pelts in the world, with an estimated 40% of the world’s market share.15 But similar to the experience in the Netherlands, the fur industry has been ravaged by COVID-19, with at least 216 out of 1,139 farms now coping with outbreaks. Most troublingly, using genomic sequencing, researchers have now identified several mutant strains of SARS- CoV-2 that arose on Danish mink farms, including one that has now resulted in an outbreak in the general human population, with more than 200 identified cases of human infection of this mutated virus.16 More than a quarter million Danes in the region of Denmark where this mutant strain arose went into lockdowns as a result of this new mutated virus, and the UK banned all travel with Denmark.
Public health researchers and authorities across the globe are profoundly alarmed by this development. The WHO stated on November 6, 2020:
Minks were infected following exposure from infected humans. Minks can act as a reservoir of SARS-CoV-2, passing the virus between them, and pose a risk for virus spill-over from mink to humans. People can then transmit this virus within the human population. Additionally, spill-back (human to mink transmission) can occur. It remains a concern when any animal virus spills in to the human population, or when an animal population could contribute to amplifying and spreading a virus affecting humans. As viruses move between human and animal populations, genetic modifications in the virus can occur. These changes can be identified through whole genome sequencing, and when found, experiments can study the possible implications of these changes on the disease in humans.17
Danish authorities immediately recognized the gravity of the threat, with the state epidemiologist stating there is a potential that we will have “a pandemic that will start all over again, starting from Denmark.” Authorities have already issued an order to cull all of the mink and shut down their large mink farming industry until at least 2022. Danish Prime Minister Mette Frederiksen gave an emergency press conference about the situation, where he stated:
We have a great responsibility towards our own population, but with the mutation that has now been found we have an even greater responsibility for the rest of the world. The mutated virus in minks could pose a risk that future vaccines won’t work as they should. It risks being spread from Denmark to other countries. The eyes of the world are on us. 18
The Inexcusable Lack of American Response
In contrast with many European nations, mink farms in the United States have been largely allowed to go about their business with minimal impediments or changes to their practices. It remains unclear whether or not the government is even employing regular testing or systematic genomic surveillance on mink farms in America. Variants could have already arisen on U.S. mink farms, or they may arise later in 2021 and we wouldn’t even know. We appear to be pursuing an unwritten policy of willful ignorance.
In August 2020, the United States reported its first confirmed cases of COVID-19 outbreaks on mink farms, with thousands of mink dying due to a respiratory disease. Utah officials wrote in an internal email dated August 10, 2020 that “farm personnel are experiencing upper respiratory infections and one farm manager has died from SARS- CoV-2 infection.”19 This mortality event was never publicly disclosed by authorities, and as late as October, Dr. Dean Taylor, state veterinarian for Utah, was continuing to downplay the threat, telling the media and the public that authorities in Utah “genuinely don’t feel like there is much of a risk”20 emanating from mink farms in Utah. The state of Utah has still refused to disclose how it is monitoring these outbreaks and whether or not it is employing any proactive genomic surveillance or testing of workers or mink on Utah mink farms.
The state of Utah is failing in its response to the COVID-19. The World Health Organization maintains a manual for communicating with the public during an outbreak of infectious disease. This manual urges that government authorities be as transparent as possible with the public during a pandemic about the nature of the outbreak and the ways in which leaders are responding to the crisis. Specifically, it states:
“Outbreak control can be severely impeded when political authorities, motivated by economic rather than public health concerns, decide to withhold information about an outbreak, downplay its significance, or conceal it altogether.”21
The only reason the death of a farm manager became known is that UARC obtained emails from the Washington State University diagnostic laboratory via a state open records request. The Utah Department of Agriculture and Food (UDAF) continues to resist releasing any records about its investigations into COVID-19 outbreaks on Utah mink farms.
Over the following four months, COVID-19 outbreaks continued to be steadily identified on Utah fur farms, as well as on mink farms in Oregon, Wisconsin, and Michigan. As of January 15, 2020, there were 16 confirmed cases of COVID-19 on U.S. mink farms – 12 in Utah, 2 in Wisconsin, 1 in Michigan, and 1 in Oregon.22
Utah’s failure to respond appears to be a pattern in every state. Not only are officials in these states resisting any widespread testing or surveillance, they have paradoxically argued that such programs would be too dangerous. Oregon state veterinarian Dr. Ryan Scholz stated that “[t]he USDA and the CDC have advised against [testing and surveillance on mink farms] for a number of different reasons, not the least of which, for us to go onto those farms and do that testing, it actually poses a pretty high risk of introducing the virus onto the farm.”23Wisconsin officials have also told the media that they will be keeping details about the COVID-19 outbreaks on mink farms largely confidential.24
The evidence is clear. There is a significant risk in allowing mink farms in the United States to continue operating as normal. Beginning in March, most mink farms will begin their “breeding season,” followed by their “whelping season” in April & May. During these Spring months, these farms will repopulate with thousands of new mink, who will be immunologically naïve and susceptible to COVID-19 infection. In the precise moment that this nation is trying to quickly and rapidly deploy our vaccines to more than 100 million Americans, we are allowed a small, dying industry to thwart these efforts, by acting as a fertile ground for viral replication, mutation, and transmission. This is the height of foolishness. The Biden Administration and each Governor in a state with a mink farming industry must intervene now to stop this breeding before it starts and ensure that mink farms do not lead to another wave of infections or a dangerous variant strain of the virus that will undermine our ongoing vaccination efforts.
1 Plowright RK, Parrish CR, McCallum H, et al. Pathways to zoonotic spillover. Nat Rev Microbiol. 2017;15(8):502-510. doi:10.1038/nrmicro.2017.45. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5791534/.
2 Munir K, Ashraf S, Munir I, et al. Zoonotic and reverse zoonotic events of SARS-CoV-2 and their impact on global health. Emerg Microbes Infect. 2020;9(1):2222-2235. doi:10.1080/22221751.2020.1827984. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594747/.
3 Gorman, James. Mink and the coronavirus: what we know. The New York Times. November 11, 2020. Available at https://www.nytimes.com/article/mink-coronavirus-mutation.html.
4 Video of this statement is available at https://www.youtube.com/watch?v=o9dvnHcP2n0.
5 Oreshkova N, Molenaar RJ, Vreman S, et al. SARS-CoV-2 infection in farmed minks, the Netherlands, April and May 2020. Euro Surveill. 2020;25(23):2001005. doi:10.2807/1560-7917.ES.2020.25.23.2001005. Available at https://pubmed.ncbi.nlm.nih.gov/32553059/.
6 Representative photographs from mink farms can be viewed here.
7 Government of the Netherlands. COVID-19 detected at two mink farms. 26 Apr 2020. Available at https://www.rijksoverheid.nl/actueel/nieuws/2020/04/26/covid-19-geconstateerd-op-twee-nertsenbedrijven.
8 Boklund A, Hammer AS, Quaade ML, et al. SARS-CoV-2 in Danish Mink Farms: Course of the Epidemic and a Descriptive Analysis of the Outbreaks in 2020. Animals (Basel). 2021;11(1):164. Published 2021 Jan 12. doi:10.3390/ani11010164. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828158/.
9 Waltenburg MA, Victoroff T, Rose CE, et al. Update: COVID-19 Among Workers in Meat and Poultry Processing Facilities ― United States, April–May 2020. MMWR Morb Mortal Wkly Rep 2020;69:887-892. DOI: http://dx.doi.org/10.15585/mmwr.mm6927e2
10 Nguyen LH, Drew DA, Joshi AD, et al. Risk of COVID-19 among frontline healthcare workers and the general community: a prospective cohort study. Preprint. medRxiv. 2020;2020.04.29.20084111. Published 2020 May 25. doi:10.1101/2020.04.29.20084111. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7273299/.
11 U.S. Department of Agriculture Foreign Agriculture Service. Dutch mink industry to close in 2021 due to coronavirus. Report Number NL2020-0042 dated Sep. 2, 2020. Available at https://apps.fas.usda.gov/newgainapi/api/Report/DownloadReportByFileName?fileName=Dutch%20Mink%20Industry%20to%20Close%20in%202021%20Due%20to%20Coronavirus%20_The%20Hague_Netherlands_08-28-2020.
12 Reuters. Netherlands to close mink farms after coronavirus outbreaks. Aug. 27, 2020. Available at https://www.reuters.com/article/us-health-coronavirus-netherlands/netherlands-to-close-mink-farms-after-coronavirus-outbreaks-idUSKBN25N2W2.
13 He, Shanshan and Han, Jie, A Dreadful Loop: Can Reverse Zoonosis of COVID-19 Seed Unrestrained Spread and Mutations in Wild Species and Transmission of Novel Strains to Humans?. SSRN. Published 2020 Oct 27. Available at https://ssrn.com/abstract=3721791.
14 Olival KJ, Cryan PM, Amman BR, et al. Possibility for reverse zoonotic transmission of SARS-CoV-2 to free-ranging wildlife: A case study of bats. PLoS Pathog. 2020;16(9):e1008758. Published 2020 Sep 3. doi:10.1371/journal.ppat.1008758. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7470399/.
15 Olsen, Jan M. North Denmark in lockdown over mutated virus in mink farms. Associated Press. Nov. 6, 2020. Available at https://apnews.com/article/mutated-virus-mink-farm-denmark-lockdown-98ede7f921eb6ef3b312e53743fc3edb.
16 Murphy, Simon and Beaumont, Peter. Travel to UK from Denmark banned amid worries over COVID in mink. The Guardian. Nov. 7, 2020. Available at https://www.theguardian.com/world/2020/nov/06/coronavirus-mutation-danish-mink-spreads-to-214-people.
17 World Health Organization. SARS-CoV-2 mink-associated variant strain – Denmark. Nov. 6, 2020. Available at https://www.who.int/csr/don/06-november-2020-mink-associated-sars-cov2-denmark/en/. Attached as Exhibit P.
19 Dyer O. Covid-19: Denmark to kill 17 million minks over mutation that could undermine vaccine effort. BMJ. 2020;371:m4338. Published 2020 Nov 9. doi:10.1136/bmj.m4338.
19 To view the documents obtained by UARC via a FOIA request, click here.
20 Aleccia, JoNEL. Thousands of minks Dead in COVID outbreak on Utah farms. Associated Press. 5 Oct 2020. Available at https://apnews.com/article/virus-outbreak-utah-animals-archive-2863345161adeebb318a3276e35e9501.
21 World Health Organization. Best Practices for communicating with the public during an outbreak. Report of the WHO Expert Consultation on Outbreak Communications held in Singapore. 21-23 September 2004. Available at https://www.afro.who.int/sites/default/files/2017-06/outbreak_com_best_practices.pdf.
22 U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA-APHIS). Cases of SARS-CoV-2 in Animals in the United States. Accessed on February 2, 2021. Available at https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/sa_one_health/sars-cov-2-animals-us.
23 Chavez, Jenn. Mink are catching the coronavirus on farms – including one in Oregon. Oregon Public Broadcasting. 8 Dec 2020. Available at https://www.opb.org/article/2020/12/08/mink-are-catching-the-coronavirus-on-farms-including-one-in-oregon/
24 Golden, Kate. Wisconsin’s No. 1 mink farming industry now seen as a COVID-19 risk. Wisconsin Watch. 30 Jan 2021. Available at https://www.wisconsinwatch.org/2021/01/wisconsins-no-1-mink-farming-industry-now-seen-as-a-covid-19-risk/.
- Schlanger, Zoë. The Mink Pandemic is No Joke. The Atlantic. 23 Dec 2020. Available at https://www.theatlantic.com/health/archive/2020/12/minks-pandemic/617476/.
- Oude Munnink BB, Sikkema RS, Nieuwenhuijse DF, et al. Transmission of SARS-CoV-2 on mink farms between humans and mink and back to humans. Science. 2021;371(6525):172-177. doi:10.1126/science.abe5901. Available at https://pubmed.ncbi.nlm.nih.gov/33172935/.
- Boklund A, Hammer AS, Quaade ML, et al. SARS-CoV-2 in Danish Mink Farms: Course of the Epidemic and a Descriptive Analysis of the Outbreaks in 2020. Animals (Basel). 2021;11(1):164. Published 2021 Jan 12. doi:10.3390/ani11010164. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828158/.
- Oreshkova N, Molenaar RJ, Vreman S, et al. SARS-CoV-2 infection in farmed minks, the Netherlands, April and May 2020. Euro Surveill. 2020;25(23):2001005. doi:10.2807/1560-7917.ES.2020.25.23.2001005. Available at https://pubmed.ncbi.nlm.nih.gov/32553059/.
- Welkers MRA, Han AX, Reusken CBEM, Eggink D. Possible host-adaptation of SARS-CoV-2 due to improved ACE2 receptor binding in mink. Virus Evol. Published online December 7, 2020. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7798643/.
Utah Animal Rights Coalition
Utah Animal Rights Coalition (UARC) is a 501(c)3 non-profit organization dedicated to promoting veganism and ending cruelty to animals. UARC is working towards a more humane and just world for animals through programs of coalition-building & community service programs, public education & advocacy efforts, and campaigns & legal reform.
You can contact UARC at: