NEW YORK — States are rolling back lockdowns, but the coronavirus isn't done with the U.S.

Cases are rising in nearly half the states, according to an Associated Press analysis, a worrying trend that could intensify as people return to work and venture out during the summer.

In Arizona, hospitals have been told to prepare for the worst. Texas has more hospitalized COVID-19 patients than at any time before. And the governor of North Carolina said recent jumps caused him to rethink plans to reopen schools or businesses.

There is no single reason for the surges. In some cases, more testing has revealed more cases. In others, local outbreaks are big enough to push statewide tallies higher. But experts think at least some are due to lifting stay-at-home orders, school and business closures, and other restrictions put in place during the spring.

The increase in infections pulled stocks down sharply Thursday on Wall Street, dragging the Dow Jones Industrial Average more than 1,800 points lower and giving the S&P 500 its worst day in nearly three months. The infections deflated recent optimism that the economy could recover quickly from its worst crisis in decades.

The virus is also gradually fanning out.

“It is a disaster that spreads,” said Dr. Jay Butler, who oversees coronavirus response at the U.S. Centers for Disease Control and Prevention. “It's not like there's an entire continental seismic shift and everyone feels the shaking all at once.”

Outbreaks in China, Italy and Spain have calmed down, but Brazil, India and other countries that were spared initially are seeing large increases. The world is seeing more than 100,000 newly-confirmed cases every day, according to Johns Hopkins University.

The following numbers on the coronavirus pandemic were compiled from the regular news releases from the state Department of Health.Thursday’s COVID-19 statistics:Butler CountyConfirmed cases: 228Negative tests: 4,452Deaths: 12PennsylvaniaNew cases: 467Total cases: 77,313New deaths: 51Total deaths: 6,113Negative tests: 476,439Recovered: 72 percentSurrounding CountiesAllegheny: 1,923 confirmed cases; 38,693 negative; and 171 deathsArmstrong: 65 confirmed; 1,522 negative; and 5 deathsBeaver: 591 confirmed; 4,449 negative; and 75 deathsClarion: 30 confirmed; 767 negative; and 2 deathsLawrence: 78 confirmed; 1,783 negative; and 8 deathsMercer: 101 confirmed; 2,104 negative; and 6 deathsVenango: 13 confirmed and 730 negativeWestmoreland: 459 confirmed; 12,005 negative; and 38 deaths.