Legionnaires’ disease causes and symptoms as health officials investigate Toronto outbreak

An outbreak of Legionnaires’ disease in downtown Toronto is currently under investigation by Toronto Public Health (TPH).

In a news release on Monday, health officials said the outbreak has occurred in an approximately one-kilometre radius of the intersection of Bathurst Street and Dupont Street, with six confirmed cases identified among people who live, work or have visited the area.

The source of the outbreak is yet to be confirmed, but TPH said possible sites have been identified and precautionary control measures have been implemented. Local hospitals and health partners have also been notified to help identify any additional cases.

Legionnaires’ disease is a serious form of pneumonia caused by a bacterium found in natural water sources. Symptoms can include fever, coughs and muscle pain, and while most cases can be successfully treated with antibiotics, some individuals are at greater risk from the disease.

News Release: Toronto Public Health investigating Legionnaires’ disease cases in Bathurst Street and Dupont Street area #TorontoNews https://t.co/nlj1cIircB

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Legionnaires’ disease is a respiratory illness caused by a type of bacteria that lives in water called Legionella, and can result in a serious chest infection or pneumonia.

The bacteria are naturally present in water sources and can also be found in man-made water systems such as cooling towers, hot tubs, sprinkler systems, humidifiers and decorative fountains.

According to the Public Health Agency of Canada (PHAC) , symptoms of Legionnaires’ disease include fever, chills, headache, confusion, muscle pain, loss of appetite, symptoms of pneumonia (such as cough and shortness of breath), and abdominal pain with or without diarrhea.

Toronto City’s webpage explains that symptoms usually start two to ten days after exposure but can be up to 19 days after exposure.

Symptoms of Pontiac fever, which is a mild illness caused by breathing in Legionella bacteria, usually start 24 to 48 hours after exposure but can range anywhere from five to 72 hours.

Legionnaires’ disease is a serious form of pneumonia, while Pontiac fever is a milder illness without pneumonia. In severe cases, symptoms can progress quickly to organ failure and death.

However, most cases of Legionnaires’ disease can be treated successfully with antibiotics, while people with Pontiac fever generally recover on their own within a week.