Nine patients have died this month with symptoms of an unidentified respiratory illness at Glengarry Hospital in Victoria, B.C., according the Vancouver Island Health Authority.

Since the end of March, a total of 19 elderly patients have come down with respiratory symptoms in the hospital's Chandler Unit, where an outbreak of the Norovirus is also underway.

Medical reviews are now being conducted for the nine patients who have died, to determine what role the respiratory condition played in their deaths.

The health authority has described all of the patients who have died as "elderly and frail with multiple medical challenges," and five were already receiving palliative care.

Lab tests not yet been able to confirm what is causing the respiratory problems, but tests have ruled out influenza A and B and H1N1.

No staff members at the hospital have experienced symptoms of the mysterious illness, and no other units of the hospital have been affected.

The health authority is now asking family members of Chandler Unit residents to stay away from the hospital, especially if they are sick.

The hospital is also limiting contact between patients, serving residents' meals in their rooms and requiring staff members and visitors to wear protective masks, gowns and gloves when visiting affected patients.