Health officials believe four Michigan residents infected with a coronavirus strain linked to minks are the first known animal to-human COVID-19 cases in the U.S., the Detroit Free Press reported April 17.
The news outlet reports that although this marks the first known evidence of animal-human spillover cases in the country, there may be other such cases that have gone unreported.
Six notes:
1. The four individuals — a taxidermist, his wife and two mink farm employees — have fully recovered.
2. Michigan's investigation into the mink outbreak started in October 2020. Samples from two farm employees who tested positive had virus mutations also present in those from mink on the farm. The state agriculture department at the time issued a statement saying: "There is currently no evidence that animals, including mink, play a significant role in spreading the virus to humans in Michigan."
3. Two months later, a taxidermist tested positive with the same mutations, as well as a fourth person in February. State health officials said it is unclear whether the mutations came directly from mink on the farm or whether they had been circulating in the community.
4. There is evidence of spillover cases in other countries, including Canada. Researchers in February presented what they believe to be the first evidence of a human contracting COVID-19 from white-tailed deer in Ontario, Canada.
5. The CDC recently updated its animal testing guidance webpage to relect that surveillance efforts in wildlife at the state level "are now critical for early detection and prevention of virus spillover from animals, specifically wildlife, to people." In a statement to the news outlet, the CDC said animal testing is recommended at mink farms "if the animals show signs of having coronavirus or if their exposure to people who've had the virus is unknown." Active, routine surveillance is not required.
6. There have been at least 18 known COVID-19 outbreaks among minks on mink farms in the U.S., according to data from the Department of Agriculture cited by the Detroit Free Press.
Editor's note: Becker's has reached out to the state's health department and will update the report as more information becomes available.