In Quebec, a discreet enemy lurks where you least expect it: in the water system we use every day. Summer is here and the bacteria may be hiding in your water system! Understanding Legionnaires' disease is essential in order to protect yourself from it.

Legionnaires' disease is caused by the bacterium Legionella pneumophila. The bacterium can be found, for example, in poorly maintained water systems, water heaters, showerheads, misting systems, hot tubs, cooling towers, etc. It strives in warm water, between 20°C and 50°C. The disease is spread by inhaling fine water droplets in the air (aerosols) and not by drinking the water.¹

The infection can present in two forms. Have you ever experienced headaches, nausea, loss of appetite and fatigue without knowing why? This could be the mild form called Pontiac fever. Rest assured, it usually clears up in 2 to 5 days.²

It does not require any clinical treatment in most cases. On the other hand, there is a more severe form called Legionnaires' disease. It is characterized by severe pneumonia that develops 2 to 10 days after exposure. It causes high fever, difficulty breathing, and a dry cough. Its mortality rate is approximately 5 to 15%.³ The disease is more common and more severe in the following cases: the elderly, people with diabetes or chronic lung disease, smokers or people with a weakened immune system.

Why is Legionnaires' disease taken seriously in Quebec?

In 2012, one outbreak occurred in Quebec City, affecting 181 people, 13 of whom died.⁴ This case marked a turning point in the fight against Legionnaires' disease in Quebec. The risk is significant for the aging population, particularly for those heavily represented in hospitals and long-term care facilities (CHSLDs), where poorly maintained water pipes could lead to widespread contamination. These individuals are the most likely to develop the more severe form of the disease.

Now that you know more about its impact, everyone can take small steps in their daily lives to reduce the risk.

Actions to take

As with any illness, cleaning is always a good preventive measure. Let's do the same to prevent Legionnaires' disease! Regular cleaning and maintenance of the showerhead, spa and humidifier help eliminate bacterial colonies.

Because cooling towers project fine water droplets into the air, they can pose a risk of bacterial growth. This type of equipment is commonly used in buildings in Quebec, and the Régie du bâtiment du Québec has established a document to outline best practices for its maintenance.

For more information, you can consult this document Règlement sur l’entretien d’une installation de tour de refroidissement à l'eau.⁶

Now that you know a little more about Legionnaires' disease, talk to those around you: above all, do not let it ruin your summer or theirs.

Comme pour toute maladie, le nettoyage est toujours une bonne pratique comme moyen de prévention. Faisons de même pour prévenir la légionellose! Un bon nettoyage et entretien régulier du pommeau de douche, spa et humidificateur permet d’éliminer les colonies de bactéries.

Comme les tours de refroidissement projettent de fines gouttelettes d’eau dans l’air, elles peuvent présenter un risque de prolifération. Ce type d’équipement est couramment utilisé dans les bâtiments au Québec et la Régie du bâtiment du Québec a mis en place un document pour encadrer les bonnes pratiques de leur entretien. Pour plus d’information, vous pouvez consulter ce document Règlement sur l’entretien d’une installation de tour de refroidissement à l'eau.⁶

Maintenant que vous en connaissez un peu plus sur la légionellose, parlez-en à votre entourage: surtout ne la laissez pas gâcher votre été ni le leur.

References

1. Canadian Centre for Occupational Health and Safety. (n.d.). Legionnaires' disease. https://www.ccohs.ca/oshanswers/diseases/legion.html

2. Government of Quebec. (n.d.). Legionnaires' disease. https://www.quebec.ca/en/health/health issues/a-z/legionellosis

3. Quebec Lung Association (n.d.). Legionnaires' disease. https://poumonquebec.ca/maladies/legionellose/

4. Institut national de santé publique du Québec. (n.d.). Legionnaires' disease. https://www.inspq.qc.ca/eau/effets-sur-la-sante/legionellose

5. Government of Canada. (n.d.). Legionnaires' disease (Legionnaires' disease and Pontiac fever). https://www.canada.ca/en/public-health/services/infectious-diseases/legionella.html

6. Régie du bâtiment du Québec. (n.d.). Regulation respecting the maintenance of a water cooling tower installation. https://www.rbq.gouv.qc.ca/les-grands-dossiers/tours-de refroidissement-a-leau/reglement-sur-lentretien-dune-installation-de-tour-de-refroidissement-a leau/

Legionnaires' disease: Number 1 enemy in Quebec