The Sault Area Hospital has declared an Influenza A outbreak on the 3C acute care unit.
A statement from the local hospital says one patient has tested positive for the virus and two others are showing respiratory-like illnesses.
Effective immediately, the 3C medical unit will be closed to visitors until further notice.
Exceptions may be permitted on compassionate grounds and at the discretion of staff.
The hospital is working closely with Algoma Public Health to monitor the situation.