COVID-19 in farmed Mink in the Netherlands

A new study published on the preprint server bioRxiv* in May 2020 reports the development of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in farmed mink in two locations in the Netherlands.

Even as the new COVID-19 pandemic continues to spread to new parts of the world, causing respiratory illness, which can be life-threatening in a significant percentage of cases, it is becoming apparent that it can also infect several animals in experimental conditions.

For instance, Rhesus and cynomolgus macaques, ferrets, and cats are known to allow viral replication in the cells of the respiratory tract, and some species develop mild to moderate disease. Domestic pets have also been known to develop infection transmitted from their human owners as well. Strikingly, several tigers in the Bronx were also found to develop respiratory symptoms after contracting the infection.

Study: SARS-CoV2 infection in farmed mink, Netherlands, April 2020. Image Credit: Gallinago_media / Shutterstock
Study: SARS-CoV2 infection in farmed mink, Netherlands, April 2020. Image Credit: Gallinago_media / Shutterstock

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

The Mink Story Begins

In April 2020, two mink farms close to each other were reported to be harboring infected minks showing respiratory symptoms like runny noses. A few of the animals showed severe breathing trouble. The mortality between the date of reporting and April 30, 2020, was about two- to four-fold the expected mortality of 0.6%. The animals were found throughout the farms, which at this time consisted mainly of females carrying litters.

Lung tissue from three recent mink corpses was subjected to PCR analysis, with one sample per farm being sequenced as well. In the next week, 36 fresh corpses were necropsied, and PCR was done on nasopharyngeal and rectal swabs of each animal.

Pneumonia and Viral RNA Confirmed

The results at necropsy showed that 28/36 animals had interstitial pneumonia, while other organs appeared grossly normal. Mink without pneumonia showed changes that could be attributable to other diseases such as obstructed labor, septicemia, or chronic Aleutian disease.

Seven lungs were microscopically analyzed, confirming the diagnosis, but bacterial cultures were negative in all cases.

PCR of throat, lung, nasal, and rectal swabs from all seven animals for which microscopic tissue analysis had been done were positive for viral RNA. One liver and three intestine specimens were also positive, but no spleens.

Throat swabs from all necropsied animals were positive for viral RNA, and 34 of the 36 rectal swabs. Viral loads were higher in throat vs. rectal swabs.

The viral sequences from the index animals as well as another 9 animals from the second batch showed that the SARS-CoV-2 was probably introduced separately into the two farms. They vary by 9 and 15 nucleotide mutations, respectively, from the Wuhan reference genome. Sequences from each farm form one cluster, but the two index sequences, one from each farm, differ at 22 nucleotide sites. The deletion of 3 nucleotides at one specific location caused the amino acid, aspartic acid to be deleted at one site.

The Link to Human Infection

The public health services investigated for the source of the animal outbreak among the farmworkers. They found that one worker on one farm had symptoms of the disease since the start of April but had not been investigated further. On the second farm, one worker had been diagnosed and hospitalized with COVID-19 at the end of March. No viral RNA could be recovered from either worker.

Dust sampling in the air between the mink houses, at three different locations, showed that viral RNA was present in 4/9 samples.

The study reveals that human COVID-19 symptoms preceded mink symptoms, the viral sequences closely resemble those of the virus in the one confirmed human case and other human sequences, and the virus was probably introduced separately to each farm.

The Routes of COVID-19 Transmission in Mink

The mink probably spread the infection to each other once it was introduced by the human farmworkers. Mink cages are constructed separately, with non-porous cage partitions. Direct contact between mink is, therefore, not possible.

Indirect spread may have occurred through particles of feed or bedding which were provided by the workers, by infectious aerosols from other animals, or by fecal contamination of the bedding, which spread as dust. The presence of viral RNA in the dust, which was airborne and, therefore, subject to inhalation, shows that the infectious particles could spread via dust or droplets as well, as well as offering an occupational risk for other workers on the farm.

This is the first report on the occurrence of human COVID-19 infection in farmed mink. The conclusions are: “Mink are susceptible to infection with SARS-CoV-2 virus, may develop the respiratory disease with typical pathological findings of viral pneumonia, and can transmit the virus amongst each other.” The animals also present a potential source of infection to farmworkers, indicating the need for biosecurity measures to keep the infection isolated within the farms.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Journal references:

Article Revisions

  • Mar 21 2023 - The preprint preliminary research paper that this article was based upon was accepted for publication in a peer-reviewed Scientific Journal. This article was edited accordingly to include a link to the final peer-reviewed paper, now shown in the sources section.
Dr. Liji Thomas

Written by

Dr. Liji Thomas

Dr. Liji Thomas is an OB-GYN, who graduated from the Government Medical College, University of Calicut, Kerala, in 2001. Liji practiced as a full-time consultant in obstetrics/gynecology in a private hospital for a few years following her graduation. She has counseled hundreds of patients facing issues from pregnancy-related problems and infertility, and has been in charge of over 2,000 deliveries, striving always to achieve a normal delivery rather than operative.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Thomas, Liji. (2023, March 21). COVID-19 in farmed Mink in the Netherlands. News-Medical. Retrieved on November 22, 2024 from https://www.news-medical.net/news/20200521/COVID-19-in-farmed-Mink-in-the-Netherlands.aspx.

  • MLA

    Thomas, Liji. "COVID-19 in farmed Mink in the Netherlands". News-Medical. 22 November 2024. <https://www.news-medical.net/news/20200521/COVID-19-in-farmed-Mink-in-the-Netherlands.aspx>.

  • Chicago

    Thomas, Liji. "COVID-19 in farmed Mink in the Netherlands". News-Medical. https://www.news-medical.net/news/20200521/COVID-19-in-farmed-Mink-in-the-Netherlands.aspx. (accessed November 22, 2024).

  • Harvard

    Thomas, Liji. 2023. COVID-19 in farmed Mink in the Netherlands. News-Medical, viewed 22 November 2024, https://www.news-medical.net/news/20200521/COVID-19-in-farmed-Mink-in-the-Netherlands.aspx.

Comments

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment
Post

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Link between COVID-19 and long-term risk of autoimmune and autoinflammatory connective tissue disorders