The U.S. recorded over 71,000 new coronavirus cases on Thursday, marking the highest single-day increase since July. Data tracked by Johns Hopkins University also reported more than 850 deaths tied to the novel coronavirus.

California, Florida, Illinois, Wisconsin and Indiana were among states that saw the highest increase in cases, contributing to the nation’s total of 8.4 million illnesses. As of Friday, the U.S. has reported 223,059 COVID-19-related deaths since the outbreak began.

CORONAVIRUS IN THE US: STATE-BY-STATE BREAKDOWN

The surge comes as a number of states across the Midwest grapple with how to handle the influx of cases and patients, while some businesses and residents continue to defy closure orders and public health measures. In North Dakota, for instance, where the state saw a new case high reported on Tuesday, officials have asked residents to conduct their own contact tracing if they test positive for the coronavirus.

The uptick in illnesses have left contact tracers in the state overwhelmed and strapped for resources, officials said. The state has also reported a backlog in case investigations.

ILLINOIS BARS, RESTAURANTS REBEL AGAINST CLOSURE ORDERS

In Wisconsin, health care professionals urged residents to practice social distancing and wear face masks as the hospital system risks becoming overwhelmed. The state opened a field hospital last week, and recently admitted its first patient, according to local reports.

“We are thankful to have this facility available to Wisconsinites and our hospitals, but also saddened that this is where Wisconsin is at today,” Gov. Tony Evers said, in a statement. “Folks, please stay home. Help us protect our communities from this highly-contagious virus and void further strain on our hospitals.”

CLICK HERE FOR COMPLETE CORONAVIRUS COVERAGE

For its part, the Centers for Disease Control and Prevention (CDC) on Thursday updated guidance to reflect a new definition for “close contact.” The health agency said it now includes multiple, brief exposures to the virus that adds up to over 15 minutes within 24 hours. The change may prompt health officials to reconsider how they conduct contact tracing.