The findings are a reminder that human health and that of animals are intertwined, and that negligence for other animal species could prolong the pandemic.
People have infected wild deer with Covid-19 in a handful of states, and there is evidence that the coronavirus has spread among deer, according to recent studies that outline findings that could complicate the path out of the pandemic.
Scientists took a swab from the nostrils of white-tailed deer in Ohio and found evidence that humans had spread the coronavirus to deer at least six times, according to a study published last month in Nature.
About one-third of the deer studied had active or recent infections, the study said. Similar research in Iowa of tissue from deer that had been run over and shot found widespread evidence of the virus.
