Toronto Public Health has identified a TTC cooling tower as the source of a six-case Legionnaires’ disease outbreak.
Toronto Public Health has identified a cooling tower at the Toronto Transit Commission’s (TTC) Hillcrest Complex as the source of a recent Legionnaires’ disease outbreak in the city.
Officials had been investigating six confirmed cases among people who lived, worked or visited within approximately a one-kilometre radius of Bathurst and Dupont streets. The affected individuals developed symptoms between July 2 and July 26.
Environmental samples collected from the TTC cooling tower matched a clinical sample from one of the confirmed cases. Based on epidemiological and environmental findings, Toronto Public Health said it was confident that the cooling tower was the source. The affected cooling equipment has been taken offline, and remediation measures are underway.
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What Is Legionnaires’ Disease?
Legionnaires’ disease is a serious form of pneumonia caused by Legionella bacteria.
The bacteria naturally occur in water and can multiply in poorly maintained human-made water systems. These include cooling towers, hot tubs, sprinkler systems, humidifiers, and decorative fountains.
When contaminated water becomes aerosolized into tiny droplets, people can become infected by breathing in those droplets.
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How Did the TTC Cooling Tower Cause the Outbreak?
Cooling towers use water as part of the process of removing heat from large buildings or industrial systems.
If Legionella bacteria multiply in a contaminated water system, the bacteria can potentially become airborne through tiny water droplets. People nearby may then inhale the contaminated droplets.
In this Toronto outbreak, environmental testing from the Hillcrest Complex cooling tower matched a clinical sample from one of the confirmed patients, helping public health officials identify the source.
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How Many People Were Affected?
Toronto Public Health investigated six confirmed Legionnaires’ disease cases linked to the community outbreak.
The cases involved people who lived, worked, or had visited the area around Bathurst and Dupont streets. Symptoms were reported between July 2 and July 26. No deaths have been reported from this outbreak.
Officials also identified a possible epidemiological link between this outbreak and a separate cluster of five Legionnaires’ disease cases at Castleview Wychwood Towers, a long-term care home located in the same area.
Legionnaires’ disease generally does not spread from person to person.
Unlike respiratory infections such as influenza or COVID-19, the main route of infection is inhaling contaminated water droplets containing Legionella.
What Are the Symptoms of Legionnaires’ Disease?
Symptoms can develop after exposure to Legionella and may include:
• Fever
• Cough
• Shortness of breath
• Muscle aches
• Headache
• Fatigue
• Chest discomfort
Because Legionnaires’ disease is a type of pneumonia, severe infections can require hospitalization.
People at higher risk of serious illness include older adults, smokers, and people with underlying health conditions, including certain chronic lung or kidney diseases, diabetes, and weakened immune systems.
Why Are Cooling Towers Linked to Legionnaires’ Disease?
Cooling towers can provide suitable conditions for Legionella growth when their water systems are not properly maintained.
Other potential sources include:
• Hot tubs
• Decorative fountains
• Humidifiers
• Sprinkler systems
• Building water systems
When contaminated water is released as fine droplets, people in the surrounding environment may inhale the bacteria.
How Can Legionnaires’ Disease Be Prevented?
Preventing Legionella growth in water systems is an important part of outbreak prevention.
Measures include:
• Proper maintenance of cooling towers and building water systems
• Regular monitoring and cleaning of water systems
• Appropriate disinfection of potentially contaminated systems
• Following public-health and building-safety guidelines
• Prompt investigation of suspected Legionella contamination
People at higher risk should also follow local health advisories during confirmed outbreaks.
Conclusion
The identification of a TTC Hillcrest Complex cooling tower as the source of Toronto’s recent Legionnaires’ disease outbreak provides an important breakthrough in the public-health investigation. Six community cases were confirmed, while a separate cluster at a nearby long-term care facility involved five cases.
Although Legionnaires’ disease can cause serious pneumonia, Toronto Public Health says the risk to the general public remains low. Taking the affected cooling equipment offline and carrying out remediation can help prevent further exposure.
Reference:
- How Legionella Spreads – (https://www.cdc.gov/legionella/causes/index.html How Legionella Spreads)
- Legionellosis – (https://www.who.int/news-room/fact-sheets/detail/legionellosis)
Source-Medindia