Coronavirus testing is offered at a lab in Niles, Ill. (Nam Y. Huh/AP)

The nation registered more than 128,000 new coronavirus infections Friday, a third consecutive single-day record, as the runaway pandemic continued its spread across the American heartland and reached deep into Florida, Texas and other parts of the country.

Illinois set a staggering record for the state of 11,790 confirmed and probable cases for the day, a much greater total than recorded Friday by more populous states such as California and New York. Arkansas, Kansas, Minnesota, Missouri and North Dakota also were among the states grappling with unprecedented cases of the coronavirus.

“It is community spread everywhere,” said Jaline Gerardin, an epidemiologist at Northwestern University Feinberg School of Medicine in Chicago. In part, the greater numbers are the result of the increased availability of testing, she said. But the main problem was allowing the virus to simmer at fairly high levels throughout the summer, particularly among young people who congregated in bars and restaurants against expert advice.

“I think it ended up busting out of their own age group,” she said. “It spread out from there, and what we’re seeing now is it’s in every age group. . . . It’s just everywhere.”

The current case totals are an echo of late March, when, according to epidemiologist Ali Mokdad, the first surge probably peaked at more than 283,000 cases per day.

But there was no way to know at the time, because the U.S. testing regime was so inadequate, said Mokdad, chief strategy officer of population health for the Institute for Health Metrics and Evaluation at the University of Washington.

With those limitations, the United States did not record its 120,000th infection overall until March 28, more than two months after the first case was identified in Snohomish County, Wash., records show. On Friday, the nation registered more cases than that in a single day.

To date, the virus has killed nearly 236,000 people in the United States and infected more than 9.7 million, according to data analyzed by The Washington Post.

Friday’s alarming caseload may soon seem quaint. Without a coordinated national strategy for containing the virus, Mokdad’s institute is forecasting more than 305,000 cases a day by Dec. 31 and more than 686,000 a day if all restrictions are relaxed. Universal mask-wearing and other steps could bring that down to 172,000, the models show.

At current infection rates, there is only a short time left to prevent overwhelming the nation’s hospital system, Mokdad said.

That will require a national mask mandate, or some way of forcing states to adopt mandatory mask-wearing, and a coordinated plan to move staff and patients from hospitals with capacity to others that lack it, if necessary, he said.

The public and businesses will need time to prepare if tighter measures or even stay-at-home orders are coming, he said. Stronger restrictions may be necessary to protect lives, the medical system and jobs, he said.

“We are heading into a dark time, and we have to be extremely careful right now not to overwhelm our hospitals,” Mokdad said. “Time for unity. Time to face our common enemy.”

For a glimpse of what may lie ahead, the United States need only look at Europe and Asia, where authorities have begun to roll out much tougher restrictions. China has banned entry to non-Chinese    nationals     from 10 countries on three continents as infections rise worldwide. Greece became the latest nation to bar residents from leaving their homes for all but a handful of essential tasks.

In London, more than 100 people were arrested Thursday night during a demonstration against England’s month-long lockdown, which took effect earlier in the day. The London Metropolitan Police said in a statement that the majority of arrests were for breaches of the new lockdown rules, which include a 10 p.m. curfew and a ban on large gatherings.

The English city of Liverpool, one of the hardest-hit places in the country, began mass testing of its residents, including people who don’t have symptoms. The pilot effort is part of the British government’s vision to test everyone in the country every week, a plan known as Operation Moonshot.

The goal, government ministers said, is that blanket testing will allow a return to greater normalcy, under which people could go to work or elsewhere without worrying about spreading the virus. Liverpool residents can go to a new testing center that can produce results in as little as 20 minutes.

In Austria, Health Minister Rudolf Anschober warned that “the second wave is much stronger, more serious, more dynamic and more powerful.” The country could run out of beds in intensive care units within weeks, he said.

In Denmark, where a coronavirus mutation has started spreading from minks to humans, authorities ordered the closure of most businesses in seven affected communities Thursday and told residents not to venture outside the municipal boundaries, according to the Danish newspaper Politiken. All 15 million minks in the country will be killed by the country’s military and police.

The British government Friday reimposed its quarantine requirement for any travelers arriving from Denmark, citing the coronavirus outbreaks at that country’s mink farms.

Since June, more than 200 coronavirus infections linked to minks have been detected, Reuters reported. The mutation that triggered the decision to kill the country’s mink population has so far been found in only 12 people. Scientists consider that mutation particularly concerning because the infected individuals showed less ability to produce antibodies, which could reduce the potential effectiveness of a vaccine.

The World Health Organization said Friday that it is in touch with Danish authorities and is still analyzing the situation.

Antonia Noori Farzan, Rick Noack and Karla Adam contributed to this report.

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