KING OF PRUSSIA, Pa. (CBS) — Officials say a Children’s Hospital of Philadelphia doctor at the King of Prussia site who tested positive for coronavirus treated approximately two dozen patients prior to his diagnosis. The cardiologist is currently in critical condition at the Hospital of the University of Pennsylvania, officials say.

The doctor was confirmed to have COVID-19 in the evening of Sunday, March 8.

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In a statement Tuesday, CHOP said affected areas were closed that night and on Monday afternoon, all families were notified of the diagnosis. All units have since bee cleaned and reopened.

“As we gathered additional information about this situation, we learned that this physician traveled abroad to a country with known COVID-19 cases, but not on the Level 3 travel advisory list as designated by the CDC. After returning to work, the physician saw patients over four days during the week of March 1, when progressive symptoms resulted in the physician ultimately seeking medical attention,” CHOP President and CEO Madeline Bell said in a statement.

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A source tells CBS3 the doctor was in Egypt where he may have gotten infected.

“In total, the physician cared for approximately two dozen patients directly and came into contact with 17 staff members. We have provided instruction to all potentially exposed individuals to self-quarantine in accordance with CDC and Pennsylvania Department of Health guidelines. Staff and patient families who become symptomatic have been advised to obtain testing from the Pennsylvania Department of Health,” Bell said.

A 62-year-old woman from Upper Merion, believed to be married to the cardiologist from CHOP, also tested presumptive positive for COVID-19. Her condition is not known.

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The doctor’s diagnosis prompted several schools to close this week after students and staff might have been exposed while at the facility.