SALEM — An Oregon mink farm will remain under quarantine after additional animals tested positive for COVID-19, state agriculture officials announced Jan. 12.
A second mink believed to have escaped from the farm was also captured and tested positive for the virus, fueling activists' concerns about a "viral reservoir" in the wild that could threaten public health.
Officials have not identified the farm or disclosed its location for privacy reasons. Oregon has 11 permitted mink farms with an estimated 438,327 total animals.
Dr. Ryan Scholz, state veterinarian for the Oregon Department of Agriculture, said the mink likely contracted COVID-19 from workers at the farm. Scholz visited the farm for the first time on Nov. 23, and collected 10 mink samples that were sent to Oregon State University and USDA for testing. All samples came back positive.
Subsequent testing on Dec. 21 revealed no positive tests out of 62 samples collected, indicating that perhaps the virus had run its course. But on Jan. 11, the USDA National Veterinary Services Laboratories confirmed two positive tests out of another round of 62 samples.
"These are new infections, not reinfections," Scholz said. "Genome testing also confirms that all the infected mink have the same strain of SARS-CoV-2 with no mutations. This is positive news because it is very likely the new infections occurred during regular operations, which includes moving the animals and some consolidation."
Outbreaks of COVID-19 in farmed mink have been reported in Oregon, Utah, Michigan and Wisconsin, as well as six countries around the world.
Authorities in Denmark culled the country's entire population of 17 million farmed mink after discovering a mutated strain the virus, igniting concerns about whether it would undercut the effectiveness of a vaccine.
Scholz said the department will not lift its quarantine on the farm until it completes two consecutive rounds of negative testing, per recommendations from the Centers for Disease Control and Prevention.
Until then, USDA Wildlife Services, under the direction of the Oregon Department of Fish and Wildlife, is continuing to trap and test local wildlife to track whether the virus is spreading.
Since December, biologists have captured and tested more than a dozen animals, including 10 opossums, three cats, two skunks and three mink. All these animals tested negative, except for two of the mink, which tested positive for low levels of the virus.
The first mink that tested positive was caught Dec. 13, and the second was caught Dec. 24, according to ODA. Based on the location, size and condition of the animals, USDA and ODFW believe it is likely they had recently escaped confinement at the farm.
"Biologists are doing an outstanding job of trapping wildlife near the farm, ensuring the virus does not affect nor establish itself in other wildlife," Scholz said.
Not everyone agrees.
Lori Burd, environmental health director with the Center for Biological Diversity, said that given more mink are testing positive and a few have managed to escape, "it's clear that this facility poses too great of a threat to wildlife and public health to continue operating."
"With two of three escaped mink found in the wild testing positive for COVID-19, regulators must take immediate action to shut down this facility," Burd said.
On Jan. 15, the Center filed a petition to ODFW seeking to add mink to the state's prohibited species list.
Michael Whelan, executive director of Fur Commission USA, a trade group based in Medford, Ore., pushed back against environmentalists' concerns. Whelan said there are no documented cases of mink-to-human transmissions of COVID-19, and accused the Center of Biological Diversity of trying to incite fear and panic.
"There have been these groups who have been trying to destroy our farms and our farmers for 40 years," Whelan said. "They're just taking this opportunity to renew their efforts."
Mink farmers in Oregon work 365 days per year to keep their animals safe and healthy, Whelan said, while producing some of the finest quality fur anywhere in the world.
"This is really a human story," he said. "These small families have been raising minks for generations ... It's unfortunate that a small sector of society wants to put them out of business."