Toronto Public Health officials have identified a cooling tower at the Toronto Transit Commission’s Hillcrest Complex as the source of a legionnaires’ disease outbreak in the city.
According to the investigation, six confirmed cases were identified within approximately one kilometre of the intersection of Bathurst and Dupont streets. The source was determined after samples collected from the TTC cooling tower matched a sample from a legionnaires case.
“Taken together with the epidemiological and environmental findings from TPH’s investigation, local public health officials are confident that the cooling tower was the source of the outbreak,” said Dr. Shima Shakory, associate medical officer of health.
The investigation also identified a possible epidemiological link between this outbreak and five additional legionnaires’ disease cases at Castleview Wychwood Towers, a long-term care home in the area.
Four of the confirmed cases were among TTC employees, according to Stuart Green, a spokesperson for the transit agency. The TTC took immediate action upon learning of the outbreak. “We immediately took steps to identify and mitigate risk in potential sources,” Green stated. “This included shutting down cooling systems in two buildings that were identified as having legionella bacteria present. Further, we brought in a contractor to conduct testing and assist in the process of deep cleaning the two systems.”
Legionnaires’ disease is caused by legionella bacteria found in water sources, including hot tubs, sprinkler systems, humidifiers, and decorative fountains. The disease is contracted by breathing in small water droplets containing the bacteria. According to public health officials, legionnaires’ disease does not spread from person to person, and the risk to the public remains low.
Key facts
- Six confirmed legionnaires cases were identified within one kilometre of Bathurst and Dupont streets
- A TTC cooling tower at Hillcrest Complex was confirmed as the outbreak source through matching bacterial samples
- Four TTC employees were among the confirmed cases
- Five additional cases at a nearby long-term care home may be epidemiologically linked
- The TTC shut down cooling systems in two buildings and brought in contractors for testing and deep cleaning
- Legionnaires disease does not spread person-to-person and poses low risk to the public