Certain white-tailed deer populations in Illinois, New York, Michigan and Pennsylvania have been exposed to COVID-19, a study conducted by the United States’ Department of Agriculture (USDA) found.
SARS-CoV-2 antibodies were detected in 33 percent of the 481 samples collected for the study from January 2020 through 2021 in the four US states.
Antibodies are an immune response to infection and their presence does not necessarily point to a current infection.
Michigan had the highest proportion of exposure, with 60 percent of the deer samples testing positive for COVID-19 antibodies, followed by Pennsylvania at 34 percent, New York at 18 percent and Illinois at 7 percent, according to the USDA.
“We do not know how the deer were exposed to SARS-CoV-2. It’s possible they were exposed through people, the environment, other deer, or another animal species,” a statement on the USDA’s website read.
“Further research is needed on the significance of SARS-CoV-2 antibodies in free-ranging white-tailed deer, including how the deer were exposed to the virus and potential impacts, if any, to overall deer populations, other wildlife, and people.”
The researchers stated that while searching for clinical signs of illness in the deer was not the focus of their study, there were no reports of clinical illness associated with COVID-19 in the deer that were surveyed.
The agriculture department’s Animal and Plant Health Inspection Service is working closely with the country’s Department of Interior, the Centers for Disease Control and Prevention (CDC) and the Association of Fish and Wildlife Agencies to determine what should be done next.