October 01, 2020

Large numbers of minks on two Utah farms died during August outbreaks with the SARS-CoV-2 virus.

State authorities have imposed quarantines on both farms.

Dr. Dean Taylor, Utah’s state veterinarian, said during an Aug. 17 press conference the farms requested diagnostic testing in response to unusually high death rates. But he didn’t know what those death rates were or how they compared with expected rates, and state and federal agriculture authorities were still investigating how the disease spread to the animals.

“Utah is one of the top breeders of mink in the United States, and the Department of Agriculture and Food, we are committed to addressing this issue boldly for the safety and future of mink farming in the state,” he said.

Workers on both farms developed COVID-19. Bradie Jones, spokeswoman for the Utah Department of Agriculture and Food, said her agency didn’t immediately have details on whether the human or animal infections were discovered first, how many people were infected, or whether those people developed severe disease.

Dr. Taylor said he saw no evidence the workers contracted the virus from minks and indicated that the risk of animal-to-human transmission remained low.

In an announcement about Utah’s outbreaks, officials with the U.S. Department of Agriculture Animal and Plant Health Inspection Service said they had monitored previous outbreaks on mink farms in the Netherlands, Denmark, and Spain and responded with guidance for U.S. mink farmers.

When infections spread this spring on mink farms in the Netherlands, at least two workers likely contracted the virus from the animals, according to a June 12 article in Science. The severity varied by animal and farm, as one farm reported a negligible increase in mink deaths and another lost almost 10% of its animals, the article states.

National Geographic reported June 24 that Dutch authorities had ordered depopulation of a half-million minks to stop the spread of the virus, which by then had caused infections on 17 farms in the Netherlands. The country’s parliament voted to halt mink breeding, accelerating plans to end the mink industry in 2024, the article states.

A July 14 report in Veterinary Pathology says that, among the first four farms with confirmed infections, daily mortality rates doubled or tripled for about four weeks. Many animals developed breathing difficulties and nasal discharge, and animals that stopped eating were often found dead the following day.

Feral cats around those Dutch farms also had antibodies against SARS-CoV-2, according to an article published June 11 in Eurosurveillance.

Dr. Taylor said Utah implemented testing on farms with SARS-CoV-2 infections and is considering whether to test on other farms.

U.S. mink farms produced about 2.7 million pelts in 2019, and about one-fifth of those came from Utah farms, according to the U.S. Department of Agriculture National Agricultural Statistics Service. Utah is the second-largest mink producer, behind Wisconsin.