July 17 (UPI) -- Friday brought another record spike for the COVID-19 pandemic in the United States -- more than 77,000 additional cases, breaking the previous single-day mark by almost 10,000 patients.
The national case total since the start of the pandemic is about 3.58 million and there have been 138,300 deaths in the United States, according to Friday's update. The death toll grew by nearly 1,000 on Thursday.
Adm. Brett Giroir, a top health expert and member of the White House Coronavirus Task Force, said Friday most new cases are coming from those who have COVID-19 but show no symptoms.
"Most of the spread are from asymptomatic people, particularly young adults, so you have to cast a wide net," Giroir told CNBC. "I think we're able to do that."
Florida, the U.S. epicenter of the outbreak, has contributed the most to the growing national tally. Friday, the state's congressional delegation sent a letter to Gov. Ron DeSantis asking for "strong action to slow the spread."
"We ask that you immediately impose a statewide mask order and stay-at-home orders recommended by public health officials in parts of the state where the outbreak is raging," the letter states.
"By failing to reopen our state in the safe, smart, and step-by-step manner that you promised, and by ignoring CDC gating criteria, our state may be forced into a statewide economic shutdown, either by your order or simply because Floridians and visitors do not feel safe."
The letter was signed by Florida's 13 Democratic representatives in the U.S. House.
Miami-Dade County Mayor Carlos Gimenez has issued a mandatory mask order, but has not given a stay-home order. The county has seen more COVID-19 cases than any other in Florida.
Texas on Thursday set a new single-day record for deaths, 154, and the third consecutive day of at least 100.
Hospitalizations, however, decreased slightly, indicating they may be stabilizing.
Texas Gov. Greg Abbott said numbers prove that new lockdown measures are not yet needed.
"We are certainly not out of the woods yet, but this could be a glimmer of hope coming if people will continue to practice wearing face masks wherever possible," Abbott told KRIV-TV. "The only way we can avoid a shutdown is if we do get everyone buying in to this process of wearing face masks."
South Carolina also recorded a one-day record of 69 deaths Thursday.
"These are people from our community who are loved dearly by family and friends who continue to die every day because of COVID-19," state epidemiologist Dr. Linda Bell told reporters. "This virus is real, it's everywhere, and it's continuing to cause death and disease all across the state."
In California, San Diego County officials reported a record 17 deaths -- and young people between the ages of 20 and 39 have accounted for nearly half of all new cases, said county health officer Dr. Wilma Wooten.
"Some young people think they're invincible and won't get sick," she said. "Not only are they getting sick, but they are also ending up at emergency rooms."
Los Angeles County set another new record of 4,600 new cases, officials said.
"We have hit concerning milestones," said county Public Health Director Barbara Ferrer.
"Without aggressive action on the part of every person, we will not get back to slowing the spread."
Nevada also broke its daily record for new cases, 1,447. Officials said new cases grew by 3.6% during the seven-day period ending July 15 -- and the positivity rate Thursday was 24.3%.
In Illinois, travelers from Iowa and Oklahoma to Chicago must now also quarantine for two weeks on arrival. The two states officially joined the quarantine list on Friday.The rule had already affected travelers from other states on the list -- Alabama, Arkansas, Arizona, California, Florida, Georgia, Idaho, Louisiana, Mississippi, North Carolina, Nevada, South Carolina, Tennessee, Texas and Utah.
Chicago Mayor Lori Lightfoot said the city is entirely relying on travelers from those states to report their condition, but isn't devoting any resources to enforcing the rule.