Many white-tailed deer in the United States have been infected with COVID-19, casting a shadow on the pandemic fight, reported Canada's Global News website.
"Finding the virus in wild animals could spell the end for any hopes of completely eliminating COVID-19 in humans," the report on Monday quoted scientists as saying.
If the virus circulates in the wildlife population, it can mutate into new variants and become a source to reinfect humans, it added.