It's very difficult to determine exactly where someone contracted Hepatitis C, but the number of Dr. Christiane Farazli's patients getting letters telling them they've contracted the disease is growing.

The law firm representing some of her patients said five people have now been told their test results came back positive for Hepatitis C after being treated by the doctor.

Robert Chenier said he got a phone call a few days ago with his test results.

"The lady on the phone said you came in contact with Hepatitis C somewhere," he said. "So I don't know what's going on."

Chenier said he had been an intravenous drug user years ago, which is one of the risk factors associated with the disease.

However, he said he got tested in 2007 and it came back negative.

He underwent both an endoscopy and colonoscopy at Dr. Farazli's clinic a few years ago and said he's not sure what this all means.

"If she gave it to me it's sad . . . very very sad," he said.

Dr. Farazli is currently being investigated by the College of Surgeons and Physicians of Ontario for improper cleaning techniques.

Merchant Law Group said the plaintiffs are looking for compensation.

"The claim alleges bodily injury, and for the judge to decide whether injuries were caused by the clinic or some other source," said Nicholas Robinson with the law firm.

Ottawa Public Health said it has sent almost 7,000 letters out to her former patients, given a colonoscopy or endoscopy between April 2002 and June 2011.

They said about 3,400 people have undergone blood tests so far, and the risk of disease was very low - the risk of contracting Hepatitis B was one in a million, Hepatitis C was one in 50 million and HIV/AIDS was one in three billion.

Robinson said two other patients have tested positive for other infectious diseases that could be related to the case.

In a memo to city council, Dr. Isra Levy of Ottawa Public Health said with the number of people being tested, he expects some positive results.

The challenge, according to him, it to figure out exactly where they became infected.

Rebecca Soroka, the main plaintiff in the lawsuit who tested negative for infection, said the anxiety and fear are overwhelming.

"Now we have five, how many more?" she said. "It's not fair."

With a report from CTV Ottawa's Joanne Schnurr