The third case of the COVID-19 in South Africa was confirmed on Sunday.
The Grayston Preparatory School, north of Johannesburg, has been closed for the day.
The move follows reports that one of the educators had been in contact with a person who has tested positive for the coronavirus.
The Gauteng Education Department could only confirm the closure of the school, but referred other matters to the National Health Department.
A memorandum from the school reiterates that the educator has not tested positive for the virus.
So far, three South Africans have tested positive.
They had all been to Italy, the epicentre of the coronavirus outside Asia to date.
The school is the second in South Africa to close over the virus.
Last week, Cowan House Preparatory School closed after a parent of two of its pupils tested positive for the coronavirus.
The children’s mother has now been confirmed to have contracted the virus.
The young ones were also tested and found to be negative, but they will remain in self-quarantine.
The deep cleaning of their school continues on Monday.
The school’s management has said it will consult with health authorities, ahead of the planned re-opening of the school on Tuesday