Health officials in London, Ontario are investigating an outbreak of Legionnaires’ disease that has affected 43 people so far this year with most of the cases reported just in the past week. One person has died.
The outbreak is centered in southeast London, where most of the cases live or work within a 6-kilometre radius. Legionnaires’ disease is a serious lung infection caused by breathing in small droplets of water that contain the Legionella bacteria. It is not spread from person to person.
Dr. Joanne Kearon, Medical Officer of Health with the Middlesex-London Health Unit, said testing is underway but the exact source hasn’t been identified.
“We did find Legionella in some of the sites. However, it wasn’t the strain that was causing the outbreak,” she said. “So, we are still looking for a potential source and have started environmental sampling this year.”
The bacteria can grow in warm, moist environments like cooling towers, air conditioners, hot tubs, and large building plumbing systems but not in regular tap water. That means the risk to the public remains low, according to public health officials.
“It’s not that it’s coming from the water,” Kearon added. “Typically, it is found in systems such as cooling towers, air conditioners, hot tubs… warm, moist environments.”
The health unit is encouraging residents, especially those with lung conditions, seniors, or people with weak immune systems, to monitor for symptoms such as high fever, cough, chills, and shortness of breath. Anyone feeling unwell is advised to seek medical attention.
While the investigation continues, public health says the outbreak may eventually fade on its own even if the exact source is never found.
