The outbreaks are believed to have started with infected workers on mink farms passing the virus to small animals.
Scientists believe it is “plausible” that the minks then sent it back to staff and are exploring the danger the animals pose.
In Spain, the outbreak at a mink farm near La Puebla de Valverde infected 14 staff, including the owner, in late May.
After the closure of operations, two other employees tested positive for COVID-19[feminine[feminine.
More than 92,000 mink have been slaughtered after more than 90% of them are thought to have contracted the virus.
After the epidemic of the NetherlandsProfessor Wim van der Poel, who studies animal viruses at Wageningen University and research, said the strain of the virus in animals was similar to that in humans.
“We assumed there was a possibility that this would be passed on to people again,” he added.
At the start of the epidemic, it was assumed that the oronavirus was initially transmitted from an animal, believed to be bats, but this was never confirmed.
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If mink is proven to be able to transmit the disease to humans, this would be the first documented case of animal-to-human transmission.
The World Health Organization (WHO) is aware of the epidemic in mink farming, but believes that animal-to-human transmission was “very limited”.
Dr Maria Van Kerkhove, WHO, said: “This gives us clues about which animals may be infected and it will help us learn more about the potential animal reservoir of (virus)”.
In the Netherlands, more than a million mink have already been killed on 26 farms, according to the National Food and Consumer Safety Authority.
Protocols on farms in Spain and the Netherlands have been tightened and the transport of mink has been banned.