Michael Coston
Editor, Senior Moderator
Viruses: Replication and Transmission of Influenza A Virus in Farmed Mink
#18,996
Mink are highly susceptible to both influenza A and SARS-CoV-2 infection, and over the past 16 years we've looked a a number of concerning spillovers, including:
Over the past decade we've seen literally dozens of reports of spillovers into mink, including the generation of mink-variant COVID strains which - at least temporarily - circulated in humans in Europe back in 2020 (see Preprint: Emergence & Spread of SARS-CoV-2 Variants from Farmed Mink to Humans and Back - Denmark, June-November 2020)..
Alarms were raised, again in the fall of 2022 when H5N1 began spreading rapidly through a large mink farm in Spain (see Eurosurveillance: HPAI A(H5N1) Virus Infection in Farmed Minks, Spain, October 2022).
This mink-derived H5N1 virus from Spain carried a rare mutation (PB-T271A), which is believed to `enhance the polymerase activity of influenza A viruses in mammalian host cells and mice'. In 2023 the CDC issued an IRAT Risk Assessment On Mink Variant of Avian H5N1, finding it's scores had risen in 6 of the 10 parameters used to evaluate their zoonotic potential.
Spillovers into farmed animals are particularly worrisome, because they allow for serial transmission across a large number of hosts, which may result in host adaptation.
In 2023 we saw scores of fur farms (both mink & fox) in Finland hit by HPAI, resulting in massive culls.
Since then, new studies have continued to highlight the risks, including last January's Zoonosis & Public Health: Detection of a Reassortant Swine- and Human-Origin H3N2 Influenza A Virus in Farmed Mink in British Columbia, Canada.
All of which brings us to a new study, published 3 days ago in the journal Viruses, which finds that (among a small cohort (n=37) of Chinese farmed mink) past LPAI H9N2 exposure was quite common (89.2%), while they found no detectable antibodies for human H1N1 or avian H3N2, H4N2, H5N1, H6N6, or H11N9.
These pre-exposed mink, however, remained highly susceptible to other influenza A subtypes (only H1N1 and H6N6 were tested), raising concerns over the ability of mink to serve as `mixing vessels' for influenza reassortment.
While this study is subject to a number of limitations (cohort size, limited range of viral challenges, etc.), it provides additional evidence on the zoonotic risks of fur-farming; particularly involving mink.
I've only posted the link, and a few excerpts. Follow the link to read the study in its entirety.
Replication and Transmission of Influenza A Virus in Farmed Mink
Viruses 2026, 18(1), 9;https://doi.org/10.3390/v18010009 (registering DOI) This article belongs to the Special Issue Surveillance, Prevention, and Treatment of Avian Influenza
Farmed mink are frequently exposed to circulating influenza A viruses (IAVs), as confirmed by viral isolation and serological evidence. Previous work reveals that naïve mink serve as susceptible hosts for both avian and human influenza strains, highlighting their potential role in influenza ecology.
Notably, efficient transmission of these viruses occurred among farmed mink, confirming their potential to sustain viral exchange. These findings indicate that farmed mink represent highly permissive hosts capable of facilitating reassortment between circulating human and avian IAVs.
Given this risk, current mink farming practices may substantially increase the likelihood of a pandemic emergence. We therefore urge immediate revision, stringent enhancement, and rigorous enforcement of biosecurity protocols and active surveillance systems in fur farming operations.
(SNIP)
4. Discussion
Our study demonstrates that influenza-pre-exposed mink retain their capacity to serve as “mixing vessels” for avian and human influenza A viruses (IAVs), reinforcing the zoonotic risks associated with intensive mink farming.
(Continue . . . .)
As we've discussed previously - while the next pandemic virus could certainly emerge directly from the wild - the practice of raising millions of highly (flu & COVID) susceptible animals in densely packed farms unnecessarily raises our pandemic risks.
While there is a growing movement to ban fur farms - particularly in the EU - Poland and Russia remain major fur producers, as well as the United States and Canada.
China, however, remains the largest global producer and exporter of farmed fur, accounting for2/3rds of the world's mink farms.Reportedly fox and raccoon dogs are raised on many of these same farms, increasing the odds of inter-species transmission of novel viruses.
Whether we can summon the political will to take the necessary steps needed to prevent the next pandemic remains to be seen.
But time is definitely not on our side.
https://afludiary.blogspot.com/2025/12/viruses-replication-and-transmission-of.html
#18,996
Mink are highly susceptible to both influenza A and SARS-CoV-2 infection, and over the past 16 years we've looked a a number of concerning spillovers, including:
- In 2009's That Touch Of Mink Flu, where at least 11 mink farms in the Holstebro municipality of Denmark were reported to be infected with a variant of the human H3N2 virus.
- Also in 2007, an antigenically distinct H3N2 Swine Influenza was detected in Canadian Mink, reported in a 2009 Journal of Clinical Microbiology study called Characterization of a Canadian Mink H3N2 Influenza A Virus Isolate Genetically Related to Triple Reassortant Swine Influenza Virus.
- A year earlier CIDRAP reported on a European mink found infected with an aggressive form of the H5 flu virusin the Blekinge region of southern Sweden near where H5N1 had been detected in wild birds.
- And even as far back as 1984, a large outbreak in Swedish mink farms was found to be due to the H10N4 avian virus.
Over the past decade we've seen literally dozens of reports of spillovers into mink, including the generation of mink-variant COVID strains which - at least temporarily - circulated in humans in Europe back in 2020 (see Preprint: Emergence & Spread of SARS-CoV-2 Variants from Farmed Mink to Humans and Back - Denmark, June-November 2020)..
Alarms were raised, again in the fall of 2022 when H5N1 began spreading rapidly through a large mink farm in Spain (see Eurosurveillance: HPAI A(H5N1) Virus Infection in Farmed Minks, Spain, October 2022).
This mink-derived H5N1 virus from Spain carried a rare mutation (PB-T271A), which is believed to `enhance the polymerase activity of influenza A viruses in mammalian host cells and mice'. In 2023 the CDC issued an IRAT Risk Assessment On Mink Variant of Avian H5N1, finding it's scores had risen in 6 of the 10 parameters used to evaluate their zoonotic potential.
Spillovers into farmed animals are particularly worrisome, because they allow for serial transmission across a large number of hosts, which may result in host adaptation.
In 2023 we saw scores of fur farms (both mink & fox) in Finland hit by HPAI, resulting in massive culls.
During that protracted outbreak, in PNAS: Mink Farming Poses Risks for Future Viral Pandemics, we looked at an opinion piece by Professor Wendy Barclay & Tom Peacock on why fur farms - and mink farms in particular - are high risk venues for both flu and SARS.
Since then, new studies have continued to highlight the risks, including last January's Zoonosis & Public Health: Detection of a Reassortant Swine- and Human-Origin H3N2 Influenza A Virus in Farmed Mink in British Columbia, Canada.
All of which brings us to a new study, published 3 days ago in the journal Viruses, which finds that (among a small cohort (n=37) of Chinese farmed mink) past LPAI H9N2 exposure was quite common (89.2%), while they found no detectable antibodies for human H1N1 or avian H3N2, H4N2, H5N1, H6N6, or H11N9.
These pre-exposed mink, however, remained highly susceptible to other influenza A subtypes (only H1N1 and H6N6 were tested), raising concerns over the ability of mink to serve as `mixing vessels' for influenza reassortment.
While this study is subject to a number of limitations (cohort size, limited range of viral challenges, etc.), it provides additional evidence on the zoonotic risks of fur-farming; particularly involving mink.
I've only posted the link, and a few excerpts. Follow the link to read the study in its entirety.
Replication and Transmission of Influenza A Virus in Farmed Mink
Viruses 2026, 18(1), 9;https://doi.org/10.3390/v18010009 (registering DOI) This article belongs to the Special Issue Surveillance, Prevention, and Treatment of Avian Influenza
Abstract
Farmed mink are frequently exposed to circulating influenza A viruses (IAVs), as confirmed by viral isolation and serological evidence. Previous work reveals that naïve mink serve as susceptible hosts for both avian and human influenza strains, highlighting their potential role in influenza ecology.
In this study, we investigated whether farmed mink naturally pre-exposed to H9 retain the capacity to serve as “mixing vessels” for reassorting human and avian IAVs. Our results demonstrate that they remain fully susceptible and permissive to infection by both avian H6N6 and human H1N1 influenza strains.
Notably, efficient transmission of these viruses occurred among farmed mink, confirming their potential to sustain viral exchange. These findings indicate that farmed mink represent highly permissive hosts capable of facilitating reassortment between circulating human and avian IAVs.
Given this risk, current mink farming practices may substantially increase the likelihood of a pandemic emergence. We therefore urge immediate revision, stringent enhancement, and rigorous enforcement of biosecurity protocols and active surveillance systems in fur farming operations.
(SNIP)
4. Discussion
Our study demonstrates that influenza-pre-exposed mink retain their capacity to serve as “mixing vessels” for avian and human influenza A viruses (IAVs), reinforcing the zoonotic risks associated with intensive mink farming.
Despite serological evidence of frequent H9N2 exposure to farmed mink [1,19], these animals remained fully susceptible to heterosubtypic strains, including avian H6N6 and human-origin H1N1 viruses. Both strains replicated efficiently in the respiratory tract and exhibited sustained transmission among pre-exposed mink, confirming their potential to facilitate reassortment between avian and human IAVs.
These findings parallel observations in swine, a well-documented mixing vessel, but highlight a critical gap in biosecurity oversight for mink farming, underscoring their role as underappreciated reservoirs for viral evolution.
(Continue . . . .)
As we've discussed previously - while the next pandemic virus could certainly emerge directly from the wild - the practice of raising millions of highly (flu & COVID) susceptible animals in densely packed farms unnecessarily raises our pandemic risks.
While there is a growing movement to ban fur farms - particularly in the EU - Poland and Russia remain major fur producers, as well as the United States and Canada.
China, however, remains the largest global producer and exporter of farmed fur, accounting for2/3rds of the world's mink farms.Reportedly fox and raccoon dogs are raised on many of these same farms, increasing the odds of inter-species transmission of novel viruses.
Whether we can summon the political will to take the necessary steps needed to prevent the next pandemic remains to be seen.
But time is definitely not on our side.
https://afludiary.blogspot.com/2025/12/viruses-replication-and-transmission-of.html
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