Pandemic building shutdown prompts Legionella warning


Leaving potable and non-potable building water systems idle creates the perfect environment for Legionella bacteria growth, reports the Centre for Disease Control, the Alliance to Prevent Legionnaires’ Disease, and Purdue University, which have issued a joint warning.

“Legionella is common in many water supply sources.  Under certain conditions, such as stagnant water environments, these bacteria can thrive in biofilm, scale, and sediment within the building water system piping,” said Glenn Strelau, senior vice president at Pace Chemicals Ltd. “Yes, the municipal water supply is chlorinated, but this type of bacteria survives by living in certain amoeba, ciliated protozoa, or biofilm, allowing it to multiply and appear in finished water supplies.”

Pace Chemicals has partnered with Spartan Bioscience to provide DNA detection of Legionella bacteria throughout British Columbia, Alberta, and Saskatchewan.

Since it is an endosymbiont living symbiotically in another organism, Legionella likely already existed in the pipes. Although trace amounts rarely result in the disease, when certain Legionella is allowed to propagate and transmit to a susceptible human host, they can cause legionellosis infections.

Flushing the system by letting the water run for a while is not an option since the bacteria lives in biofilm. “Based on experience and scientific studies, expecting flushing to solve a Legionella problem in a shutdown building is unrealistic,” said Matt Freije of LAMPS (Legionella and Management Plan Support).

This is important because COVID-19 is made more harmful by the presence of other respiratory pathogens in the body with Legionella one of the main sources.

An independent study published in The Lancet medical journal in May was performed by researchers at Qingdao Women and Children’s Hospital in Qingdao, China. Of the 68 patients displaying serious respiratory symptoms from COVID-19, Legionella pneumophila was detected in 20 per cent (14 patients).

Most outbreaks of Legionella have occurred in buildings with mismanaged water systems. Bacteria thrive in buildings with HVAC systems where water condensation can collect and pool, cooling towers on roofs where standing water is common, and potable systems from water heaters that lead directly to faucets and showerheads.

The Canada Occupational Health and Safety Regulations (COHSR), part two, division three, entitled “HVAC Systems” contains the standards businesses and water treatment service providers must do to stay compliant according to the Canadian Standards Association (CSA) guidelines. These include instructions for operation, inspection, testing, cleaning, and maintenance of HVAC systems.

Employers are also required to appoint a qualified person to put the instructions into action and to complete a written report regarding actions or incidents.

Legionella is fatal in one in 10 people, but not transferrable from person to person. It is contracted when people breath in contaminated water vapour.


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