At least one patient suffered a bacterial infection and more than 500 other patients could be at risk after undergoing endoscopic procedures with contaminated tools at Victoria General Hospital.

At a press conference Thursday, Dr. Martin Wale of the Vancouver Island Health Authority said that a recent review of cleaning processes revealed traces of blood inside one of the hospital's four endoscopes.

Besides bacterial infection, the contamination means that patients could have been exposed to hepatitis A or B, or even HIV.

One patient suffering from a terminal illness contracted a bacterial infection after a pancreatic endoscopy at the hospital.

Doctors traced that infection back to the contaminated endoscope. The patient later died, but the VIHA says that the cause of death was the existing illness, and not the infection.

Despite that infection, Dr. Wale maintained that the chances of infection are very low. "The risk is less than one in 30 million, but we are taking a precautionary approach by notifying patients, because the infections are treatable."

Patients who underwent endoscopic retrograde cholangiopancreatography procedures between June, 2008, and January, 2010, received letters on Tuesday warning them of the risk of infection.

In the procedure, an endoscope is used to inject coloured dye to visualize problems of the live, pancreas and gallbladder.

The health authority is recommending testing for all patients that may have been exposed to the contaminated endoscope.