“Aggressive mitigation” efforts to thwart the new coronavirus pandemic will extend into Bucks County starting Sunday, Pennsylvania Gov. Tom Wolf said in a joint announcement with state health officials.

That means the state government is asking all non-essential businesses and public spaces to close in the county immediately to the Lehigh Valley’s south. Places like grocery stores and gas stations can remain open.

The voluntary restrictions are now being asked for four counties around the state’s COVID-19 epicenter. They first announced for Montgomery County, which now has 20 of Pennsylvania’s 47 coronavirus patients.

They were requested of Delaware County on Friday, and then of Bucks and Chester counties on Saturday. Delaware County has six reported cases; Bucks has three and Chester has two.

The announcement follows Friday’s order to close all Pennsylvania schools for 10 days, and mirror earlier requests to avoid gyms, theaters, malls and other crowded places.

Shutting down non-essential services will help slow the spread of the virus that causes COVID-19, Wolf and state Secretary of Health Rachel Levine said Saturday. They are meant to encourage people to stay home and practice “social distancing” unless it is absolutely necessary to go out.

"The government of the commonwealth can only do so much,” Wolf said, adding that success will depend on residents, businesses and institutions doing “what needs to be done.”

The mitigation efforts apply to higher education, gyms, child daycares and adult care centers. No-visitor policies are to be adopted by prisons and nursing homes.

Gas stations, grocery stores, pharmacies, government facilities, utilities and mass transit should continue to operate. There will not be restrictions on local travel.

“Even if you do not think you have been exposed, please consider others who are considered high-risk," said U.S. Rep. Chrissy Houlahan (D-Berks, Chester).

These are the main symptoms of COVID-19, the disease caused by the new coronavirus.CDC

The majority of COVID-19 cases are concentrated in the suburban Philadelphia area. There is one presumptive case in the Lehigh Valley. On Friday, officials announced the state’s first pediatric case in Monroe County.

For more information on the coronavirus, consult your state health department at health.pa.gov and the CDC website.

Steve Novak may be reached at snovak@lehighvalleylive.com. If there’s anything about this story that needs attention, please email him. Follow him on Twitter @SteveNovakLVL and Facebook. Find lehighvalleylive.com on Facebook.