The schools were closed after tests indicated dozens of students had contracted tuberculosis after a student was diagnosed late last month, Kathimerini reported Tuesday.

Affected by the closures were two elementary schools and two secondary schools, the newspaper reported.

"If we do not get the go-ahead from an expert, we cannot send our children back into those classrooms," Yiota Griva, the head of one of the secondary schools.

Griva has joined other parents and teachers in signing a petition calling for "an immediate inspection on all members of the school community" and for "full updates" on the progress of those tests.

Teacher Constantina Garane said "small basement classrooms that have not been aired in years" are a health hazard.

"It is not surprising illnesses thrive in such an environment," she was quoted as saying.