What to know
- Toronto Public Health is investigating six confirmed cases of Legionnaires’ disease among people who lived, worked or spent time around Bathurst Street and Dupont Street.
- No source has been confirmed, but public health officials are conducting inspections and environmental sampling of possible sources.
- Experts tell Now Toronto the risk to most residents remains low. Legionnaires’ disease spreads by inhaling contaminated water droplets, not through person-to-person contact or simply touching contaminated surfaces.
- Older adults and people with underlying conditions, including lung disease or weakened immune systems, face a greater risk of severe illness.
- Symptoms can include fever, cough and shortness of breath. Experts say most Torontonians do not need to change their routines, but anyone experiencing symptoms should seek medical attention.
Six cases of Legionnaires’ disease are now being investigated around Bathurst and Dupont, but infectious disease experts say most Torontonians, including people living in the area, do not need to change their daily routines.
Toronto Public Health (TPH) announced Monday that six people who lived, worked or spent time around Bathurst Street and Dupont Street developed symptoms between July 2 and July 26.
No specific sources of the water system-based bacteria have been confirmed, although TPH says possible sources have been identified and are being investigated.
Infectious Diseases specialist Dr. Isaac Bogoch told Now Toronto that despite the outbreak, the disease’s risk to most residents in the area remains low.
“The vast majority of people, even those in the area, will not be exposed to this and will not get this infection,” Bogoch said.
He added that Legionnaires’ disease can cause a serious form of pneumonia, although the illness itself is vastly uncommon.
“It’s still very rare. Even in outbreak settings, it’s still going to be quite rare, but of course it has to be taken seriously,” Bogoch said.
TPH is looking into the bacteria through on-site inspections and environmental sampling.
What is Legionnaires’ disease?
Legionnaires’ disease is a bacterial infection caused by Legionella bacteria, whose primary hosts are amoebae, but can at times infect humans as well.
The illness is not contagious and instead is transmitted through breathing in contaminated, aerosolized water droplets.
Bogoch said the most common sources could include HVAC systems, air-conditioning systems and cooling towers. Less commonly, the bacteria can be found in day-to-day activities.
Alexander Ensminger, a University of Toronto professor in the departments of biochemistry and molecular genetics, explained to Now Toronto that Legionella bacteria is more common than people think.
“We probably all encounter Legionella and Legionella pneumophila of some type in our daily lives, and we just don’t know it,” the professor said.
The bacteria can also be found in more common locations, like grocery-store vegetable misters and car washes.
“I always take a step back whenever the misters mist my vegetables, even though [there’s] only been a few outbreaks,” Ensminger explained.
Is Legionnaires’ disease transmitted through surfaces?
Ensminger said people don’t have to worry about contracting the virus through touching any contaminated surfaces.
“You would have to be actively inhaling it,” they said.
The disease also does not spread through person-to-person contact.
Why is public health investigating Bathurst and Dupont?
TPH is investigating and identifying where the impacted people could have been exposed, a crucial step in an outbreak investigation.
Ensminger shared that the first question that came to his mind when a cluster of cases is identified is where the exposure could have originated.
“It’s usually localized exposure to some sort of source of contaminated, usually aerosolized water,” he said. “The one we hear about frequently is cooling towers, and sometimes those can lead to outbreaks that are spread over a sort of large geographic area.”
Once public health officials can determine the source, they can then compare samples from people who became sick with samples taken from a potentially infected environment.
Who is most at risk?
Anyone can become infected, although Bogoch said older people and those with underlying health conditions, including compromised immune systems or lung disease, can be more likely to become seriously ill and face severe pneumonia.
What are the symptoms to look out for?
Legionnaires’ disease can look like other types of pneumonia, with Bogoch saying it might feel more intense.
Symptoms include:
- fever
- cough
- shortness of breath
He added that people experiencing those symptoms should seek medical care.
Legionnaires’ disease is able to be treated with specific antibiotics, so seeking medical assistance to recognize the infection is important.
Altering lifestyle in affected areas
Bogoch stressed that although the disease should be taken seriously if infected, people in the Bathurst and Dupont area don’t need to change their routines too much.
Ensminger, who said he lived in the area, confirmed it was business as usual.
“I went for a run in the evening after reading this news report,” he said. “And I thought, ‘Am I going to run past Bathurst and Dupont?’ And I thought, ‘Yeah, I’m going to run past Bathurst and Dupont.’ I’m not really concerned about it.”
The professor added that unless a person is caring for someone particularly vulnerable to the severe infection, they don’t need to change their routines or take any precautions as TPH studies the outbreak.
“If you live in Toronto and you do not transit anywhere near Dupont and Bathurst, you have zero reason to be concerned about this cluster of illness,” Ensminger said.
Bogoch also said the most important thing residents can do is be knowledgeable about the disease and the outbreak, ensuring they seek medical help if any symptoms develop.
TPH is also investigating whether the Bathurst and Dupont cluster could be connected to a separate 5-case outbreak at Castleview Wychwood Towers earlier this summer.
