Why Legionnaires’ disease may be the next big public health crisis

The light may be at the end of the tunnel as far as COVID-19 is concerned, but don’t start celebrating just yet, Legionella might be a ticking time bomb waiting to go off!

June 10, 2021

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Thanks to the efforts of researchers on a global scale we now have COVID-19 vaccines that are rolling out. The end of the pandemic is now in sight. That's the good news. The bad news is that there may be a potentially far more deadly disease waiting for us on the other side. A disease that was already on the rise in the years before COVID-19 hit, with a steady 650% increase in the number of cases over the 15 years up to 2018 (fig. 1). While COVID-19 has a mortality rate of just 1.8%, Legionnaires’ disease has a death rate of between 10 and 25% depending on the population it infects.





Why are we concerned about Legionella?


The causative agent behind Legionnaires’ disease is the bacteria Legionella pneumophila. Unlike COVID-19, it is a water-borne disease that thrives in stagnant water. The reason it is giving health authorities sleepless nights is that since COVID-19 was declared a National Emergency in many countries around the world in March of 2020 and stay-at-home orders were issued, many buildings have been closed and unused creating an ideal environment for Legionella.. As people began to shelter in place on a global scale, we saw business districts, office blocks, hotels, schools, universities, restaurants, and shopping malls shut their doors. Many of these facilities have been shut now for many months, heating and cooling systems have been idle or running in power save modes, water has sat in pipes and stagnated, and maintenance teams were furloughed and sent home.


Figure 1. The growing number of Legionnaires’ cases in the US before the COVID-19 pandemic.1


We have created the perfect environment for Legionella to fester and multiply. Chlorine in drinking water will dissipate significantly in just 30 days if it just sits in a pipe. Many buildings have been unoccupied for months, some for over a year. Without people using the water, running the air conditioning, etc., bacteria, including Legionella, can multiply. This event could not have come at a worse time, with much of the shut-down having occurred over the warm summer months, increasing the multiplication and breeding rate of Legionella bacteria in water supplies and cooling systems.


Legionella outbreaks are linked to events


The CDC has stated that approximately 35% of Legionella outbreaks prior to 2019 were the result of ‘events’ such as construction or water system disruptions that set off an infective event. We may just have passed through one of the greatest single ‘events’ in global history, and it remains to be seen what happens when we re-start a country again after such a long shut down.


Worse still is the fact that we may miss the start of any outbreaks as Legionnaires’ disease presents with symptoms almost identical to COVID-19; cough, pneumonia, fever, etc. Medical practitioners focused on COVID-19 may misdiagnose; doctors looking for horses rather than zebras may miss the early cases, inadvertently allowing a cluster to grow.


From the perspective of building owners, there is the stark possibility of their building being closed down again just as they were reopening. Health authorities will typically close a building, often for months, while (expensive) remediation efforts are put in place. Testing on the back end typically needs to be conducted for at least six months, sometime a year or more if the last sources of Legionella cannot be tied down. All at the building owner's expense.


Learn more about the threat of Legionella and how we can mitigate it in this webinar: Managing Legionella Risks In Building Water Systems led by Dr David Krause, founder and principal Toxicologist for HealthCare Consulting and Contracting , a consulting firm that works with clients to assess, manage, and control hazards in healthcare and other occupational settings.


In part 2 of this blog series, we'll look at what can be done on the part of building owners, municipal water suppliers, and other involved groups to minimize risk as businesses around the world reopen.


Learn more about microbiology water testing solutions for Legionella


In the event of Immediate Critical Contamination and Outbreak, please call Pall’s Emergency 24hr Outbreak Hotline: 1-866-347-3428. Pall can rapidly deploy Point-of-Use Water Filters to deliver an immediate barrier against Legionella Outbreak.


1. Image credit: Dr David Krause www.HC3FL.com, featured in the webinar Managing Legionella Risks In Building Water Systems

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