Get all the latest news on coronavirus and more delivered daily to your inbox. Sign up here.

Sen. Lindsey Graham, R-S.C., sent a letter to the Chinese ambassador to the United States on Thursday urging him to pressure his government against reopening the country’s so-called wet markets.

Graham notes that the Centers for Disease Control and Prevention believes the current coronavirus pandemic has its origins in the wildlife sold in a wet market in the city of Wuhan and that other global public health crises have been tied to these markets.

“It is well documented that wet markets in China have been the source of a number of worldwide health problems and their operation should cease immediately,” Graham said in his letter.

CORONAVIRUS IN THE US: STATE-BY-STATE BREAKDOWN

“Wet markets,” as defined by the Oxford English Dictionary, are places “for the sale of fresh meat, fish and produce.” They also sell an array of exotic animals.

While rumors have swirled that the virus originated in bats and then infected another animal that passed it onto people at a market in the southeastern Chinese city of Wuhan, scientists have not yet determined exactly how the new coronavirus infected people. But these kinds of markets are not known to operate in the most sanitary conditions.

“You’ve got live animals, so there’s feces everywhere. There’s blood because of people chopping them up,” Peter Daszak, president of EcoHealth Alliance, which works to protect wildlife and public health from emerging diseases, told the Associated Press last month.

The Huanan Seafood Wholesale Market in Wuhan, before its closure, advertised dozens of species such as giant salamanders, baby crocodiles and raccoon dogs that were often referred to as wildlife, even when they were farmed. The Chinese government has reportedly allowed some wet markets in the country to reopen as the threat of the contagion lessens, although the one in Wuhan remains shuttered.

CLICK FOR COMPLETE COVERAGE OF THE CORONAVIRUS OUTBREAK

Like many other “wet markets” in Asia and elsewhere, the animals at the Wuhan market lived in close proximity as they were tied up or stacked in cages.

Animals in “wet markets” are often killed on-site to ensure freshness – yet the messy mix raises the odds that a new virus will jump to people handling the animals and start to spread, experts say.

Dr. Anthony Fauci, the top infectious disease expert with the White House coronavirus task force, has criticized China's decision to reopen the markets, calling the move misguided, according to a tweet by Graham after a phone call with Fauci.

Fox News’ Greg Norman contributed to this report.