Officials at the Hôtel Dieu hospital in Lévis, just across the St. Lawrence River from Quebec City, held a news conference this afternoon to discuss details of the discovery.
"The risk is small, but the potential infections are important, and they are treatable. So we decided to engage in preventive screening," said François Aumont, the hospital's director of professional services.
Aumont said that because of this risk — however small — the hospital cannot take a chance that a patient might have been infected with a communicable disease.
Dr. André Vincent, the head of Hôtel Dieu's laboratory department, cited a recent study showing hepatitis B and C transmission by endoscopes is extremely rare. The same study showed no reported cases of HIV transmission through the devices.
The hospital's administration said letters will be sent to all patients affected in the coming week and it will launch a hotline to answer questions.
Dr. Rémi Lavoie, Hôtel Dieu's head of gastroenterology, said in that in mid-April hospital staff discovered a leak in one of its linear endoscopes, an instrument used to help diagnose cancer or gastroenterological malformations.
Once tests were performed on the instrument, it was discovered hospital staff had not been properly disinfecting it for the past eight years.
During that period — from June 14, 2005, until May 1, 2013 — nearly 1,000 patients at Hôtel Dieu came into contact with that endoscope.
The hospital has a record of each of those patients, and it is hoping that all will respond to an invitation to be tested for HIV as well as hepatitis B and C.
The hospital said it is launching an inquiry into how the problem occurred and who might have been responsible.
Hospital authorities said 70 per cent of the affected patients are from the Quebec City area, and 30 per cent are from other regions of the province.
Hôtel Dieu will have a hotline set up by Tuesday to respond to patients' questions. The number to call is 1-888-835-7105.