Dutch findings come as COVID-19 hits mink farms & humans in Wisconsin & Utah
GREEN BAY, Wisconsin; SALT LAKE CITY, Utah––Which came first, the COVID-19 coronavirus infecting humans, or infecting mink?
No one right now knows for sure whether mink might have been the incubator species through which COVID-19 passed from horseshoe bats in southern China to humans circa November 2019, before infecting more than 37 million people worldwide, killing 1.1 million to date; but China is fourth in the world in ranched mink production, behind Denmark and Poland, ahead of the U.S. and the Netherlands.
Repeated outbreaks among ranched mink discovered throughout 2020 are believed to have been passed to mink by humans. But do mink then pass COVID-19 back to humans, perhaps in a mutated form that spreads more easily?
Dutch scientists find 2-way infection
Medical and veterinary science are still seeking the answers to those questions, but the answer more and more appears to be yes.
Reported the October 2, 2020 edition of the European Society of Clinical Microbiology & Infectious Diseases bulletin, “A study investigating SARS-CoV-2 [COVID-19] infections across 16 mink farms in the Netherlands shows that the virus likely jumped between people and mink and back.”
Five leading Dutch veterinary scientists “did an in-depth investigation of outbreaks on 16 mink farms and humans living or working on these farms, using whole-genome sequencing to underpin sources of transmission,” the report explained.
The findings were initially presented at the ESCMID Conference on Coronavirus Disease, held online September 23-25, 2020, and were amplified worldwide by the Program for Monitoring Emerging Diseases (ProMED).
Two-thirds of mink workers tested positive
Sixty-six of the 97 mink farm employees and residents, who cumulatively had exposure to 720,000 mink, tested positive for COVID-19.
“Due to longitudinal follow up of the first four farms, we have strong evidence that at least two people on those farms were infected by mink,” the five Dutch researchers wrote.
“Unfortunately, based on our research we cannot make definite conclusions on the direction of most of the infections, so we do not know the total number of people who were infected by mink. We conclude that initially the virus was introduced from humans and has evolved on mink farms, most likely reflecting widespread circulation among mink several weeks prior to detection.”
“At least some are likely to have been infected by mink”
They add: “Genetic analysis of SARS-CoV-2 from the human employees on the farms showed they were the same as those found in mink, and were not identical to those found in unrelated SARS-CoV-2 patients living in the vicinity of farms. Genetic sequences from each of the infected mink farms fell into one of five distinct clusters, showing transmission between different mink farms.
“Additional research will be needed to determine the routes of transmission,” the Dutch team acknowledged. However, they concluded, “At least some of these employees are very likely to have been infected directly from infected mink and thereby describe the first proven zoonotic transmission of SARS-CoV-2 to humans.”
The five team members, all faculty at leading Dutch scientific universities, were Bas Oude Munnink, Wim van der Poel, Arjan Stegeman, Marion Koopmans, and Reina Sikkema.
COVID-19 hits Wisconsin
Meanwhile, while the science evolves, relevant facts include that the 67 mink farms in Wisconsin produce about half of the three million mink killed for fur in the U.S. each year; the three dozen fur farms in Utah produce about half a million more mink; and the mink farms in both Wisconsin and Utah, clustered in Taylor County and Utah County, respectively, appear to be concentrated near the epicenter of two of the fastest-spreading COVID-19 outbreaks to hit the U.S. in many months.
Reported Hope Kirwan of Wisconsin Public Radio on the morning of October 8, 2020, “The state Department of Agriculture, Trade and Consumer Protection have announced that dead mink at a farm in Taylor County have tested positive for the virus,” the first acknowledgement that COVID-19 is at large among Wisconsin ranched mink.
“The National Veterinary Services Laboratories confirmed the test results,” Kirwan added.
“Wisconsin state veterinarian Darlene Konkle said several hundred mink at the affected farm,” which was immediately quarantined, “have died so far. She said officials have not yet determined the source of the outbreak.”
State will not release location info
But, said Konkle, “The likely source of infection here was exposure to an infected person.”
Continued Kirwan, “Konkle said there is currently little evidence that infected mink or other animals can transmit the coronavirus to humans.”
Konkle also noted, though, that “Mink along with several other species in the mustelid family, including ferrets, do have lung receptors that seem to make them more susceptible to the virus than other species.”
The Wisconsin Department of Agriculture, Trade and Consumer Protection, Kirwan finished, “will not release information about the affected farm or parties involved while an investigation into the virus is active.”
Record number of cases
The same day, October 8, 2020, Tyler Clifford of CNBC reported on the evening news, Wisconsin “set a fresh one-day record of 3,132 new COVID-19 cases, topping the previous record that came just days prior, according to the Wisconsin Department of Health Services.
“With the exception of the northwest region,” Clifford observed, “the entire state has seen COVID-19 hospitalizations surge in double digits between late September and early October.
“More than 80% of Wisconsin’s hospital and intensive care unit capacities are in use, according to the state’s health department website,” Clifford mentioned, while “As many as 200 medical workers are out sick, battling their own bouts with the virus that has now infected nearly 7.6 million and led to more than 212,000 deaths in the U.S., according to data compiled by Johns Hopkins University.”
Record cases in Utah, too
Simultaneously, updated Jacob Klopfenstein of KSL in Salt Lake City, also on October 8, 2020, “Utah’s number of COVID-19 cases increased by 1,501— a new record number of cases in a single day. Five deaths were also reported, bringing the state above 500 total COVID-19 deaths since the pandemic began, according to the Utah Department of Health. Utah had 237 people hospitalized for COVID-19—another record, for current hospitalizations in any given day.”
Continued Klopfenstein, “Dr. Emily Spivak, an associate professor of medicine in the Division of Infectious Diseases at University of Utah Health, said that the university’s intensive care unit is 95% full.”
Most meaningfully as regards mink, Klopfenstein reported, “Utah’s current surge in COVID-19 cases, which has been going on for about a month, initially was centered around Utah County. At the beginning of the surge, Utah County was accounting for about 40% of the state’s new cases, despite making up only about 20% of Utah’s overall population.”
No culling in Utah
As the surge began, observed JoNel Aleccia for Kaiser Health News and Nexstar Media Wire on October 5, 2020, “Thousands of minks at Utah fur farms have died because of the coronavirus in the past 10 days, forcing nine sites in three counties to quarantine, but the state veterinarian said people don’t appear to be at risk from the outbreak.”
Instead, Utah state veterinarian Dean Taylor told Aleccia that as Aleccia summarized, “The COVID-19 infections likely were spread from workers at the mink ranches to the animals, with no sign so far that the animals are spreading it to humans.
“We genuinely don’t feel like there is much of a risk of it going from the mink to the people,” Taylor said.
According to Taylor, COVID-19 had already killed between 7,000 and 8,000 mink, while none had been culled, a measure that Taylor deemed unnecessary, Taylor said.
Utah also conceals location info
The industry trade organization Fur Commission USA informed Aleccia, she wrote, that “Fur from the dead infected animals will be processed to remove any traces of the virus and then used for coats and other garments.”
Like his Wisconsin counterparts, Aleccia said, “Taylor declined to name the farms or the counties where the affected mink were found.”
But Taylor did offer that COVID-19 is “going through the breeding colonies and wiping out the older mink and leaving the younger mink unscathed,” with most of the deaths occurring in mink “between the ages of 1 and 4 years,” Aleccia summarized.
Utah Farm Bureau regional manager Clayton Beckstead told Aleccia that about nine mink ranches in the state were quarantined. A fourth-generation mink farmer himself, Beckstead said his own mink ranch had not been hit.
“We’re certainly worried,” Beckstead allowed, “but I think everybody’s taking pretty extreme biosecurity measures.”
Denmark takes risk to humans seriously
“Extreme biosecurity measures” by Utah standards, however, fall far short of the Danish response. Acknowledging new COVID-19 outbreaks on 41 mink ranches, with outbreaks suspected on 20 more, Danish agriculture minister Mogens Jensen on October 2, 2020 announced that as many as a million mink would be culled: all of those at the infected locations, and all others within a five-mile radius.
Despite the culling, the number of Danish mink ranches known to be harboring COVID-19 rose to 89 within 10 days. By October 12, 2020, the estimated toll of mink to be culled had increased to 2.5 million.
Noted Program for Monitoring Emerging Diseases [ProMED] animal disease and zoonoses moderator Arnon Shimshony, “During the previous phases of the event on Denmark’s mink farms, with a monitoring strategy and strict restrictions for infected mink farms, the Danish veterinary services (DVFA) and the Danish health authorities assessed that it was justifiable to let infected holdings live because the risk of spreading infection to humans was seen as minimal. This policy has apparently changed.”
Denmark and the U.S. are the third and fourth nations, respectively, to acknowledge COVID-19 outbreaks on mink ranches, following the Netherlands and Spain.
Netherlands phasing out mink farming early
The Netherlands, where 57 of the 120 mink ranches in the country have been found to be afflicted with COVID-19, on August 28, 2020 announced that a complete phase-out of mink farming is to be completed by March 2021, two and a half years ahead of the previously scheduled deadline of January 1, 2024.
“As a result of the outbreak, an estimated two million mink, most of them pups, have been gassed to death,” reported the Dutch national news service NOS.
“Mink on remaining fur farms will not be preventatively culled unless new outbreaks occur,” NOS continued, “and mink on unaffected farms will be slaughtered for their pelts in November this year. Breeders are not permitted to restock. By March 2021 all remaining mink operations will be bought out by the government.”
France also announces end to mink ranching
The Dutch mink ranching shutdown will come more than 20 years after the Netherlands ended fox and chinchilla fur farming.
French environment minister Barbara Pompili on September 29, 2020 announced that the last four mink ranches in France would be closed within five years.
Twenty-one other nations still have fur farming industries. Among them are the U.S., Canada, China, Russia, all seven Scandinavian nations, Estonia, and Ireland, which has only three mink ranches still in operation.