GENEVA (AFP) -- The World Health Organization said Tuesday that Dutch workers apparently infected with the coronavirus by minks could be the first known cases of animal-to-human transmission.
The WHO told AFP that it was in close contact with Dutch researchers investigating three cases where the virus appears to have been passed to humans from minks.
"This would be the first known cases of animal-to-human transmission," the UN health agency told AFP in an email.
"But we are still collecting and reviewing more data to understand if animals and pets can spread the disease," it said.
Dutch Agriculture Minister Carola Schouten said Monday that a second worker had likely contracted COVID-19 on a mink farm, while stressing that the risk of further contagion remained low.
An initial infection was reported last week on one of two farms near the southern city of Eindhoven, where the disease was discovered in April among mink that are bred for their valuable fur.
The infection happened before it was known that the mink were carrying the virus, meaning that workers did not wear protective clothing at the time.
The health ministry said that three people on the farm tested positive for the virus, but said that it remained unclear if more than one of the cases had come directly from a mink.
The exact source of the virus, which first appeared in China late last year, remains unknown, and there is growing pressure for an international probe to determine its origin.
In a matter of months, the virus has infected more than 5.5 million people, killing nearly 350,000 of them.
Most scientists believe the virus jumped from animals to humans, possibly in a market that sells exotic animals for meat in the city of Wuhan.
WHO chief Tedros Adhanom Ghebreyesus indicated Monday that China had agreed that an investigation of the origin was needed, but did not say when one might begin.
"All stakeholders understand the importance of studying the origin, because it's by studying the origin that we can prevent it from happening in the future," he told a virtual press conference.
Since the initial jump to humans, there have been no previous reports of animals being the source of infections.
The WHO said however that there have been some instances of COVID-19 patients infecting their pets.
"A number of susceptibility studies have shown that other animal species are also susceptible to the virus and can be infected, including cats, ferrets," it said.
The agency stressed that necessary precautions should be taken to avoid infection of pets from close contacts with humans with COVID-19, but insisted that "there is no reason or justification to take measures against companion animals."