Are You Familiar with Legionellosis?

September 2nd, 2015

Legionellosis, also known as Legionnaiares' disease and Legion fever, is a respiratory infection most often caused by the Legionella pneumophila bacterium, which thrives in lukewarm water. This bacterium may find favourable conditions to multiply in water cooling towers, buildings, hot-water tanks (boilers), and spas. Legionella pneumophilia can be transmitted when it contaminates airborne water droplets. The bacterium is not transmitted from person to person.

Antibiotics are used to treat Legionellosis, which can be cured in most cases. Those at risk of suffering from complications include: smokers, those who consume large quantities of alcohol, seniors, people with chronic diseases (e.g., kidney failure, respiratory disease, heart disease, diabetes, or cancer) and those with a compromised immune system.

An ounce of prevention is worth a pound of cure!

No vaccine to prevent Legionellosis is available; however, the risk of catching the disease can be reduced by managing potential sources of infection.

To prevent Legionellosis in your home:

  • Keep the temperature of the water tank at 60 °C. The Legenionella bacterium cannot multiply at this temperature. Installing an anti-scald device at the exit valves of the shower and bath faucets to lower the temperature to 49 °C is recommended. If the hot water tank has been off for a few days, allow hot water to flow from the boiler for several minutes.
  • Clean and maintain devices which release airborne water droplets according to the manufacturer's instructions (e.g., showerheads, whirlpool baths, spas and humidifiers). Consult a qualified professional if necessary.


Legionellosis symptoms include:

  • Headache
  • Fatigue
  • Dry cough
  • Muscular pain
  • Abdominal pain
  • Loss of appetite
  • Diarrhea
  • Nausea and vomiting
  • Chest pain
  • Sputum with or without blood
  • Difficulty breathing
  • Altered mental state (delirium, confusion, disorientation, and hallucinations).

To learn more about Legionellosis, visit Portail santé mieux-être at


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