CDC: “Investigations found that mink from a Michigan farm and a small number of people were infected with SARS-CoV-2 that contained unique mink-related mutations (changes in the virus’s genetic material). This suggests mink to human spread might have occurred. The animals on the farm have since tested negative for SARS-CoV-2 twice, and the infected people have since recovered.
Finding these mutations in mink on the Michigan farm is not unexpected because they have been seen before in mink from farms in the Netherlands and Denmark and also in people linked to mink farms worldwide. Currently there is limited information available about the genetics of the SARS-CoV-2 virus that has infected people living in the communities near the mink farm. Thus, it is difficult to know with certainty whether the mink-related virus mutations originated in people or in mink on the farm.
To confirm the spread of SARS-CoV-2 from mink to people, public health officials would need more information on the epidemiology and genetics of the virus in mink, mink farm workers, and the community around mink farms. These results highlight the importance of routinely studying the genetic material of SARS-CoV-2 in susceptible animal populations like mink, as well as in people.
CDC is aware of reports of a strain of SARS-CoV-2 virus in mink in Denmark that was also present in the local human population.This strain, called “Cluster 5,”had not been seen before and was made up of five mutations. The World Health Organization (WHO)external icon reported that as of November 2020, the Cluster 5 variant was no longer circulating in Denmark. Of mink and human samples tested so far in the United States, none have contained all the mutations that make up the Cluster 5 strain.”
UPDATE 10TH APRIL 2022: US government documents reveal CDC delayed disclosing likely COVID-19 animal spillover event
A trove of government documents obtained by National Geographic provides the first behind-the-scenes look at the U.S. Centers for Disease Control and Prevention’s (CDC) investigation into a suspected COVID-19 animal-to-human spillover event in Michigan in late 2020.
