A new study of hundreds of white-tailed deer infected with the coronavirus in Iowa has found that the animals probably are contracting the virus from humans, and then rapidly spreading it among one another, according to researchers.

Up to 80 percent of deer sampled from April 2020 through January 2021 in the state were infected, the study indicated.

WASHINGTON — The Biden administration on Monday argued that the federal government had all the power it needed to require large employers to mandate vaccination of their workers against the Covid-19 virus — or to require those who refuse the shots to wear masks and submit to weekly testing.

In a 28-page filing before the United States Court of Appeals for the Fifth Circuit, which temporarily blocked the mandate with a nationwide stay last week, the Justice Department argued that the rule was necessary to protect workers from the pandemic and was well grounded in law.