New results from research into COVID-19 on mink farms

New research findings in the ongoing investigation into COVID-19 at mink farms suggest there has been a transmission of new coronavirus from mink to human. The investigation has also shown that mink with COVID-19 can be asymptomatic. Based on this new information, agriculture minister Carola Schouten and health minister Hugo de Jonge are introducing new measures.

'These new findings have a major impact on mink-farm owners and staff and their families, as well as on local communities,’ said Ms Schouten. ‘I'm in close contact with all those involved.’

The virus that causes COVID-19 mutates relatively quickly. These changes to its genetic code can be tracked. By comparing the genetic codes of the virus in different animals and people, scientists can create a ‘family tree’ for the virus and gain more insight into when and where people and animals were infected. This type of tracking has been done in the case of infected mink and people. The virus found in one staff member on a mink farm showed similarities to that found in the mink on that farm. Based on this comparison and the position of that form of the virus in the family tree, the researchers concluded that it is likely that one staff member at an infected farm has been infected by mink.

In order to clarify this finding, researchers are now continuing to map the genetic family tree of the virus in infected people in the area surrounding the mink farm in question. This will allow them to build as complete a picture as possible.

According to the National Institute for Public Health and the Environment (RIVM) the risk of the virus being transmitted from mink to human outside mink sheds remains negligible. RIVM made this risk assessment previously, after no samples of air and dust collected outside mink sheds were found to contain any trace of the virus.


Based on the new information, the government is introducing new measures on top of those already in force. Mink at all farms in the Netherlands will be screened for antibodies. In the interest of staff members’ health, it is important to gain a clear picture of the situation at all mink farms. Screening will be compulsory and will be coordinated by the Netherlands Food and Consumer Product Safety Authority (NVWA).

If a case is found at a mink farm, the same measures will be introduced as at other infected farms and staff members will be advised to use personal protective equipment at work. Furthermore, no visitors will be admitted to mink sheds on infected farms. Agriculture minister Carola Schouten had already imposed a reporting obligation on mink farm owners, veterinarians and staff at research institutes. That obligation will now be expanded, so that all symptoms pointing to COVID-19 must be reported to the NVWA. This is in addition to an existing ban on the removal of animals and manure from infected farms, a measure aimed at stopping the virus spreading to other farms.

Farm cats

This ongoing research has revealed a close similarity between the viruses found on two of the infected mink farms. There are several possible explanations for this. On one of the infected farms, antibodies to the virus were found in three out of 11 farm cats. It is therefore important to examine the potential role of farm cats in transmitting the virus. Farm cats are feral or semi-feral cats that live out-of-doors on a farm. Pending further research, mink-farm owners are advised to ensure that cats cannot enter or exit the site.


It is known that pets can contract COVID-19. The risk of people being infected by their pet remains small. RIVM’s existing advice regarding COVID-19 and animals remains unchanged: keep pets indoors if anyone in your household has COVID-19-like symptoms and the animal may have been infected. If you are in any doubt or if your pet has severe symptoms, always contact your vet. RIVM’s advice on pets can be found in full at