Ferret owners in Europe have likely shivered at the news that millions of animals looking much like their own animals are being put down across the continent as a dangerous COVID-19 mutation has spread among the mink population in fur farms. 

Just like mink, ferrets are also susceptible to COVID-19, which has a very similar effect on them as on humans, causing difficulties breathing that tend to be worse for older individuals.

Mink and ferrets belong to the same family of carnivorous mammals, which also includes otters, weasels and badgers – the Mustelidae family. Of all Mustelinae - a subfamily of Mustelidae - ferrets and mink are the most similar-looking, but the difference between them is significant.

While their wild cousin, the mink, may hiss, squeal, snarl, scratch and bite at the touch of a human, ferrets have been domesticated for at least 2,500 years – though they're known to bite occasionally.

Because ferrets can catch viruses through the nose like humans do, they're often used in medical research studying flu, SARS and other respiratory diseases. Initially hailed as key players in the race to discover efficient treatments against COVID-19, there's now concern that ferrets could potentially develop a mutated strain of the virus.

What are the risks to ferrets?

Both mink and ferrets are vulnerable to catching the virus from humans. In the case of the mink in Denmark, the virus was first transmitted from humans to mink and then quickly spread from mink to mink within a few days.

The huge size of the mink population in those Danish fur farms (the country is the world's largest producer of mink pelts) and the high-density settings in which the animals were kept allowed the virus to mutate – and for these mutations to be then transmitted to at least 214 people.

For an epidemic of COVID-19 to break out among ferrets, there should be similar conditions to the ones of the mink in fur farms. A large population of ferrets, kept in high-density settings.

"You've got animals being housed in these conditions – it's intensive farming," says Joanne Santini, professor of microbiology at University College London, UK.

"These quite large animals housed in very small cages, all stacked on top of each other. I'm not a zoologist myself, but I have heard that they do suffer respiratory problems just because of the housing conditions. I mean, you can imagine that they're not going to be as fit as a wild mink running around and they're going to be more vulnerable to the virus."

That's not normally the case for ferrets.

In the UK, there are believed to be approximately 800,000 to 1 million pet ferrets. While pet owners will likely have only a small number of ferrets in their household, there are more than 100 places in the country where ferrets are bred in large numbers for medical research purposes or for vermin control. And these places are now a cause of concern for the UK government. 

To date, only a small number of ferrets kept in captivity have reportedly fallen ill with the virus naturally, without being purposefully infected with it for research purposes. 

But although the risk for humans of being infected by ferrets is low, there's still a risk. If a human is infected with COVID-19, the chances are they could pass it on to their ferret, as the two are likely to come in close contact and share the same living spaces.

The UK authorities encourage ferret owners to exercise caution. The advice from Public Health England's Human Animal Infections and Risk Surveillance group, is to wear a face covering if possible while handling your pet, although it is recognized this is "not always feasible," and it is recommended to wash hands often when handling the animal.

If someone living in the same household as a ferret falls ill with COVID-19, health officials recommend for them to "not be involved in the care," saying "they should self-isolate from their pets, avoid kissing and cuddling them, and avoid sharing food or other items with them."

"If they have SARS-CoV-2 or they're isolating for whatever reason, they should not just isolate from people to protect people, but they should isolate from animals to not only protect the animals, but then protect the people in the long run because it could come back," says Santini. "And, you know, it's all the same measures that we're doing for preventing human-to-human transmission."

The UK's advice also adds: "Guidance is being updated to ensure any pet ferrets arriving into the UK with people who are required to self-isolate should also remain in isolation and not leave the house/property for three weeks following return to the UK.

"Note, this is a longer period specified for self-isolation compared to current human guidance, but it is based on experimental infections of ferrets where virus is cleared after two to three weeks."

Could you catch COVID-19 from your ferret?

The UK – which banned fur farming 20 years ago – is anticipating that transmission from mink or ferrets to humans could only happen in very low numbers. The risk for the general population to get infected with SARS-CoV-2 from ferrets is assessed as very low, while it is high for the animal handlers.

Ferrets are not a primary source of infection for humans, but as the opposite is more likely, it is better to keep an eye on your ferret for symptoms of COVID-19, and if they show them, take advice from a veterinarian.

"The concern is that when the virus from humans is moving into an animal reservoir or into an animal where it's not adapted and can't spread well, that ... if it survives in those animals (it can replicate and spread), you can imagine that selective pressure might give you a mutation that then allows [the virus] to be transmitted better in that animal population," explains Santini.

The fear, as in the case of the mink in Denmark, is that a mutation of the virus in animals might invalidate the effectiveness of the vaccines currently under development.

As with any other family members, pet ferrets need to be taken care of and protected from the coronavirus pandemic.

_{Cover image: Вика Скворцова/500px/VCG}