Infographic: What is Legionella
Organization: Health Canada
Date published: 2021-05-28
Legionella is a group of bacteria found in natural water sources, such as lakes, streams and groundwater. It can also be found in human-made water systems and devices.
Legionella can become a health concern when it grows in these systems and devices, and is inhaled in the form of droplets and mists released into the air.
Possible sources of Legionella
- water heaters
- decorative fountains
- showerheads and sink taps
- home plumbing systems
- building plumbing systems
- cooling towers (cooling towers for buildings)
Conditions that support Legionella growth
- warm temperatures
- standing or still water
- settled particles and biofilm (a slimy, glue-like material containing microorganisms and nutrients)
Health effects of Legionella
Legionella can cause two types of illness in humans: Legionnaires' disease and Pontiac fever.
Legionnaires' disease is a serious respiratory illness that results in pneumonia, lasting weeks to months, and can lead to death.
Pontiac fever is a milder illness, causing flu-like symptoms. People with Pontiac fever generally recover in 2 to 5 days without treatment.
Who is at greatest risk
- people over 40 years of age
- current and former smokers
- people with chronic lung disease
- people with underlying illnesses and weakened immune systems
How to reduce your risk
- Maintain your water heater temperature at 60°C
- To reduce the risk of scalding the temperature of the water at the tap should be no higher than 49°C. You should contact a qualified plumber to install mixing valves to control the tap water temperature.
- Regularly clean and disinfect mist-producing devices in your home (shower heads, humidifiers, hot tubs) according to manufacturer directions
- Run the hot and cold water taps for a few minutes after not using them for more than two weeks
- Periodically drain and flush your water heater, according to manufacturer directions, to reduce settled particles
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