HARRISBURG, Pennsylvania -- All schools in Pennsylvania will close for two weeks, Gov. Tom Wolf announced Friday as the state undertook sweeping measures aimed at slowing the spread of the new coronavirus.Wolf on Friday also announced he was extending a day-old shutdown order affecting Montgomery County to encompass Delaware County, another heavily populated Philadelphia suburb the governor said has exhibited "confirmed evidence of risk." Wolf initially announced the Delaware County order would take effect Monday, but an aide subsequently corrected that it will begin Saturday.The school shutdown order affecting more than 1.7 million school children, in public and private K-12 schools. There are now 45 confirmed cases in the state Wolf, who also has discouraged large gatherings of people statewide and canceled prison visits, said his actions are designed to save lives. He urged people to stay calm and stay home."My hope is that we've taken actions that are both decisive and absolutely appropriate," Wolf said at a news conference Friday afternoon at the Pennsylvania Emergency Management Agency headquarters in Harrisburg. "I know that some of you are worried, but we believe that, by asking everyone to cooperate and spend a few days limiting their interactions with other people, we can help control the spread of this virus in Pennsylvania."Wolf said schools will not be penalized if they are unable to reach the 180 days of instruction required under state law. His administration, he said, would evaluate the decision at the end of the 10 days and decide whether to extend it.Governors in several other states, including Maryland and Ohio, had already ordered their schools to close.Following the order, teachers' unions, the Pennsylvania School Boards Association and other school organizations released a joint statement in support of the move.Some school officials in Pennsylvania, including in Philadelphia, had warned that children who depend on free or reduced-price meals in school might go hungry. Philadelphia officials had sought to keep their schools open, saying many children have just a single parent who might not be able to work if the child is home.Wolf, however, said the state had received a waiver from the U.S. Department of Agriculture to allow eligible schools to serve meals to students in a "non-congregate setting," such as a drive-through or a grab-and-go.Mark DiRocco, executive director of the Pennsylvania Association of School Administrators, said superintendents are likely staying late Friday to try to answer numerous questions, such as how they will feed children and whether they can do online instruction in the next two weeks.Most, however, are in favor of the move, he said."There are so many unknowns about this virus and the last thing a superintendent and board want to deal with is a sudden outbreak among kids in a building, and that will fly through a community so fast," DiRocco said.The move came a day after Wolf ordered all schools, day cares and other facilities closed in hard-hit Montgomery County, in the Philadelphia suburbs and home to more than 800,000 people, and asked residents to avoid all non-essential travel. An identical order will take effect Saturday in Delaware County, home to more than 560,000 residents.Already, more than a dozen colleges and universities in Pennsylvania, including Penn State, have shifted to online instruction and are sending students home, while counties have declared emergencies and advised people against attending large gatherings. Pittsburgh Mayor Bill Peduto on Friday also declared a state of emergency.Before Wolf acted on Friday, a wave of school closings across Pennsylvania had been growing as the day wore on, with some school officials grumbling that Wolf's administration had not offered more guidance.A look at the latest developments in Pennsylvania:___CASESMost of the state's 41 cases of positive tests are in eastern Pennsylvania. Hardest hit is Montgomery County, with 18 cases. Cases announced Friday included the first two children under 18. Chester County saw its first case, as did two counties west of the Susquehanna River: Cumberland County with three and Washington County with one.The confirmed cases largely have been traced back to contact with the new coronavirus in another state or country. Most people are at home in isolation, officials say; a few are hospitalized.For most people, the new coronavirus causes only mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia, and death.The vast majority of people recover.___MONTGOMERY AND DELAWARE COUNTIESWolf has said his shutdown order will be continually evaluated and could spread to other counties. It also applies to higher education, gyms, child day cares and adult care centers.His administration said Wolf was acting under disaster emergency law that allows him to control movement and occupancy in a disaster area, but it could not say when a governor had last used that power. It also cited the Department of Health's legal responsibility to "determine and employ the most efficient and practical means for the prevention and suppression of disease."Gas stations, grocery stores, pharmacies, government facilities, utilities and mass transit should continue to operate, he said, while no-visitor policies are to be adopted by prisons and nursing homes.___CANCELLATIONSPublic programs, events and training in Pennsylvania's state parks and forests were canceled Friday through April, although parks and forests will remain open except for three parks in the Philadelphia suburb of Montgomery County. The event cancellations include special events such as races and festivals.Visitors can still camp overnight or stay in cabins and cottages, and fishing is still allowed. In Montgomery County, three state parks will be closed to visitors for at least two weeks: Evansburg, Fort Washington and Norristown Farm Park.___PRISON VISITSThe state Department of Corrections has canceled all visits with inmates for two weeks and said it will step up screening of employees and vendors, including taking temperatures and asking a series of questions.Anyone with flu-like symptoms or a temperature of 100.4 degrees or more will not be allowed in a state prison, Corrections Secretary John Wetzel said in a statement.There are no confirmed cases in state prisons.___LAWMAKERSPennsylvania state lawmakers plan to return to voting session on Monday with COVID-19 response at the top of their agenda.A House Republican majority spokesman said Friday that coronavirus-related legislation could include health-care access, insurance, health emergency declarations, workplace protection and funding.Lawmakers and the governor's office plan to meet over the weekend to sort out details.