Forty percent of deer across parts of the Midwest and Northeast are testing positive for COVID-19 antibodies.

Researchers with the U.S. Department of Agriculture tested deer for COVID-19 antibodies in Illinois, Michigan, Pennsylvania, and New York.

The results found that 7% of those tested in Illinois had been exposed to the virus, 31% in New York, 44% in Pennsylvania, and 67% in Michigan.

Eric Schauber is the Illinois State Biologist and Director of the Illinois Natural History Survey at the University of Illinois at Urbana-Champaign. Schauber says there’s a lot of unknowns surrounding how the deer contracted the virus, and it’s not clear how the virus impacts wild animals. Schauber and the USDA researchers say more research is needed to understand how the virus transferred species and how it will act in the wild.

“We do need good surveillance of wildlife diseases to know about this interchange of disease agents between people, domestic animals, and wild animals,” Schauber said.

Schauber says the deer may have become infected by coming in contact with humans, pets, or with wastewater. He also says there’s little to worry about for humans, as there is a far greater chance of catching COVID-19 from a person than a wild animal.

Those hunting deer are recommended to use gloves while cleaning the meat and to make sure it is fully cooked to destroy any potential pathogens.