New Orleans, the Louisiana city known as the "Big Easy" famed for its jazz and nightlife, has become an epicentre of the coronavirus pandemic gripping the United States.

Bourbon Street, the normally bustling heart of the French Quarter, is eerily quiet, its music silenced and its bars and restaurants shuttered.

Health experts and state officials believe it is the month-long street party in February known as Mardi Gras which contributed to the severity of the outbreak in the city of some 400,000 people on the Mississippi River.

"Mardi Gras was the perfect storm for the spread of this virus," said Rebekah Gee, Louisiana's former health secretary.

"Not only did we have people in floats, people in parties, but people from all over the world came here," Gee told the MSNBC network.

"Unfortunately, people were throwing beads, sharing drinks," she said of the tradition of revellers on floats tossing necklaces of plastic beads to crowds packing the streets.

"And they weren't only throwing beads, they were likely throwing COVID-19," Gee said.

Louisiana reported its first case of coronavirus on March 9, about two weeks after Mardi Gras culminated with its final street parades on February 25.

The southern US state now has 2,305 confirmed cases and 83 deaths. New Orleans alone accounts for 997 of the cases and 46 of the deaths.

- 'Disaster that defines our generation' -

"This is going to be the disaster that defines our generation," said Collin Arnold, director of the Office of Homeland Security and Emergency Preparedness for New Orleans, which was devastated by Hurricane Katrina in 2005.

Arnold agreed that Mardi Gras was probably responsible for the fact that the number of virus cases in Louisiana is rising at a rate higher than anywhere else in the country.

"We had over a million and a half people in the city, including international visitors, all attending parades daily," he told CNN.

State authorities ordered the closure of bars and restaurants several days after the first cases appeared but the damage had already been done.

On March 15, a Saturday night, after the order was given, it took police coming out in force to get reluctant crowds off the streets.

Video footage taken that evening shows a convoy of police cars driving slowly down Bourbon Street with their blue rooftop lights flashing and their sirens blaring.

"By order of the governor and the mayor, large groups of people are prohibited from congregating together," a police officer said over a loudspeaker.

"Your actions are jeopardizing public health," the officer said. "We are directing you to clear the streets and go back to home or back to your hotel. "Thank you for your cooperation."

- 'Hand grenade' -

Arnold said New Orleans residents have largely been abiding by the stay-at-home orders. "It's pretty empty," he said.

Louisiana Governor John Bel Edwards has issued stark warnings about the ability of the state's hospitals to deal with the expected numbers of coronavirus patients.

He said the trajectory of the growth in cases is similar to that of Italy and Spain, the worst-hit countries in Europe and demand for hospital beds and ventilators could outstrip capacity by early April.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said the shutdown in New Orleans probably should have come earlier.

"It is likely that should've been done a little bit sooner," Fauci told CNN. "I'm not blaming anyone on that. "It putters along and you think you're OK," he said. "Then it starts to go up a little and 'Bingo,' it goes up in an exponential way. "That's what's happening in New Orleans now."

Among those who have contracted coronavirus in Louisiana is Sean Payton, coach of the 2010 Super Bowl champion New Orleans Saints.

Payton, who has since recovered, took to local radio to urge New Orleans residents to practice "social distancing."

"Just picture everyone's got a hand grenade on them," he said. "How about that? So stay away from everybody."

Payton was also confident New Orleans would recover. "This city's tough and resilient," he said. "We've been through so much."

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