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July 25, 2025
London, ON—Victoria Hospital’s cooling towers at the London Health Sciences Centre (LHSC) have tested positive for legionella bacteria, the pathogen responsible for Legionnaires’ disease, according to hospital officials.
Legionella bacteria thrive in warm water environments such as hot tubs, water tanks, large plumbing networks, and air conditioning systems—particularly those where water can become vaporized. Dr. Nadim Khalil, Site Lead for Infection, Prevention and Control at LHSC Children’s Hospital, explained: “Water evaporates and becomes aerosolized, where the bacteria can be in the air, then inhaled by people, and people can get sick.”
What Is Legionnaires’ Disease?
LHSC describes Legionnaires’ disease as a serious type of pneumonia that is not transmitted person-to-person. Common symptoms include:
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Fever
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Chills
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Dry cough
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Shortness of breath
The Current Outbreak
On July 9, the Middlesex-London Health Unit declared a Legionnaires’ disease outbreak within a six-kilometre radius in southeast London. As of July 22, 2025, officials have reported 69 cases and two deaths within the affected area.
A heat map from the health unit shows the general distribution of confirmed cases, based on home addresses. Despite the case count, Dr. Khalil emphasized that the rate remains relatively low — about one in every 10,000 Londoners has contracted the illness so far.
LHSC’s Response
Although Victoria Hospital is within the outbreak’s catchment area, hospital officials state it is not the source of the outbreak. “There’s not an increased risk from catching legionella from being in the hospital than anywhere else in London,” Dr. Khalil noted. Nevertheless, the hospital has doubled its chemical cleaning efforts for the cooling tanks: “Regardless of the test results, we have had treatment done to the water supply and we are proceeding with an even more aggressive treatment and cleaning, just to make sure we’re not causing any potential harm to the community.”
The hospital is currently awaiting further analysis to determine whether the strain of legionella found in its cooling towers matches that found in community cases. Results from samples taken about a week ago are expected in approximately three weeks.
Disclaimer:
This article is based on the most recent public information as of July 25, 2025. Health situations and investigations involving communicable diseases can change rapidly. For the latest updates, please consult the Middlesex-London Health Unit or your local public health authority. This article does not substitute individualized medical advice; if you experience symptoms of pneumonia or related illness, seek medical attention immediately.
