Thousands of students at suburban public schools and private universities discovered Sunday that their schools would be mostly or entirely shuttered for the entire week.

Scarsdale, a suburb in Westchester County, north of New York City, announced that it would close its entire public school district until March 18 after a teacher at its middle school tested positive for the virus. The district said that the affected person was “exhibiting mild illness.”

Hofstra University on Long Island and Yeshiva University in Manhattan both announced on Sunday that classes would be canceled for the rest of the week.

A Yeshiva student and two faculty members tested positive for the virus last week, and a Hofstra University said that a student had begun exhibiting symptoms after attending a conference where someone had tested positive. That person is awaiting the results of their test.