The City of Orillia and the Simcoe Muskoka District Health Unit have declared their investigation into a recent Legionnaires outbreak over, saying there is no risk of further transmission of the disease associated with this particular strain of bacteria.

Back in October, the health unit and the city of Orillia announced they were investigating several cases of Legionnaires disease that had popped up in the region. Ten cases were confirmed. Each person who contracted the disease was over the age of fifty and had conditions that put them at risk.  The severity of symptoms for each person varied, but some were life-threatening, and one person died. 

What each person had in common was that they’d spent time in downtown Orillia.

“What we had to do was find out where they’d been and map out the common areas where we needed to look,” said Dr. Charles Gardner, Simcoe Muskoka District Health Unit (SMDHU) Medical Officer of Health in early November.

Legionnaire’s disease is a type of lung infection caused by bacteria that is inhaled. The bacteria travel in tiny particles of water in the air. It can be found in hot water tanks, hot tubs, humidifiers and cooling towers. 

The health unit began investigating cooling towers downtown Orillia. It discovered that the strain of legionella bacteria found in the Rotary Place cooling tower was a close match in two cases of the Legionnaire’s diseases that were included in the cluster of cases. Tests found high levels of legionella in the tower, and it was then thoroughly disinfected. Follow-up tests of the Rotary Place cooling tower have come back unable to detect legionella.

“We are declaring it over because it’s been quite a long time since the onset of the last case, which was October 2nd. That’s more than two incubation periods for legionella, and classically that’s the definition of the outbreak being over,” Dr. Gardner said on Tuesday. 

“On behalf of the City of Orillia, I would like to express our sincere sympathy to the family and friends of the individual who passed away and to those who have fallen ill,” said Orillia’s Mayor Steve Clarke. “We will be collaborating with the health unit and the province in an effort to help prevent this type of incident from happening elsewhere.”

Dr. Gardner says cases of Legionnaire’s disease are on the rise in Ontario. He says cooling towers must be maintained very carefully to prevent legionella bacteria from developing and says there aren’t rigorous regulations in Ontario to enforce that. He says the health unit will now be conducting a review, following this outbreak.

“We are going to conduct a review for best practices for maintaining sites but also for best practices for regulation, for government monitoring and enforcement of the safety of cooling towers,” he said.

The Simcoe Muskoka District Health Unit plans to send the review, along with recommendations to the province of Ontario.