The Iowa Department of Public Health confirmed on Thursday that 555 of the 2,517 employees at the Tyson Foods plant in Storm Lake have tested positive for the coronavirus, a day after state officials said they would report business outbreaks only upon request. “Businesses are not currently required to report an outbreak to the Iowa Department of Public Health,” said Sarah Reisetter, the department’s deputy director. The department said that businesses should only report to the state if 10 percent of workers are either out sick or test positive for the coronavirus—however the link that was provided for doing so is now malfunctioning. State health officials confirmed 400 new cases in Buena Vista County, which is now the state’s coronavirus hotspot with a total of 675 cases.