European Water Quality Regulation Update Aims to Reduce Legionella Outbreaks
Water quality standards across the UK and throughout the EU are vital to maintaining public health and this led to the creation of the Drinking Water Directive (DWD) in November 1998.
The DWD has been amended in the past and is now awaiting further amendments to be approved in 2020.
While the coronavirus outbreak has delayed its progression, it looks set to be voted on in the European Parliament sometime in autumn 2020.
Part of the reason why this important water quality directive was overhauled concerned outbreaks of Legionnaires’ disease across EU member states.
According to latest ECDC data cases of Legionnaires’ have risen in recent years in many EU countries.
A key driver in overhauling the DWD was the task of detecting legionella in water supplies.
If detecting this potentially dangerous pathogen in our water supplies is easier to do, many outbreaks could potentially be prevented.
Legionella pneumophila causes most cases of Legionnaires’ disease
Legionnaires’ disease is fatal in around 8 to 12% of cases, according to the ECDC.
However, rates vary depending on the people who contract the disease… and mortality rates have been noted at between 5% and 50% in individual outbreaks.
Various research studies have confirmed that up to 96% of all cases of Legionnaires’ disease occur after exposure to Legionella pneumophila.
The pneumophila variant is one of over 60 types of Legionella bacteria currently identified, it is also recognised as the most pathogenic.
Scientists clash with the Commission over water quality and legionella testing
When amendments to the existing Drinking Water Directive were being considered, the European Commission decided to recommend testing for all forms of Legionella bacteria.
However, scientists with experience in dealing with legionella and associated outbreaks recommended that water sources should only be tested for Legionella pneumophila.
They suggested that testing for the many other (sometimes harmless) strains of the bacteria would be a waste of time and resources.
Some countries focus on testing for Legionella pneumophila
France and Germany focus on testing for the most dangerous form of Legionella bacteria (Legionella pneumophila) and have done so for many years.
It can be no coincidence that comparatively, they have experienced far fewer outbreaks of Legionnaires’ disease than other member states that do not focus on this testing.
What was the outcome?
While the Commission did not switch to the scientist’s recommended approach, they did agree to let member states decide how they would target water sampling to identify harmful legionella bacteria levels in water supplies.
This included the process of checking for Legionella pneumophila.
What is the purpose of the Drinking Water Directive?
Clearly, the EU Commission wants to ensure all water supplies across member states are as safe as possible.
Cases of Legionnaires’ disease have increased in many countries in recent years.
If the trend continues, we could reasonably expect to see yet more outbreaks occurring… and this is clearly something the EU wants to stop.
While there are other bacteria that can be found in drinking water and can be harmful, legionella represents a real concern.
Outbreaks can lead to fatalities and can affect many people.
Since legionella spreads through legionella contaminated aerosols, i.e. water spray and mist, it can affect those in the area who inhale the spray – even if they do not drink any of it.
Certain water sources, such as cooling towers, spa pools, showers and drinking fountains, represent a greater risk to those in the vicinity than others.
Why is regular water quality sampling for legionella important?
If left unchecked, Legionella bacteria can quickly multiply and colonise a water system to create a serious health hazard.
It readily multiplies in stagnant water, as this encourages the development of biofilms that allow the bacteria to thrive unhindered.
Water temperatures of between 20-45 degrees Celsius also invite the bacteria to multiply.
This means that legionella testing is just one part of the approach required to combat levels of Legionella bacteria in any water system.
Implementing the changes in the new directive
It is reassuring to see that many countries are not waiting for the final vote on the amended DWD.
Since the amendments are likely to require nothing more than the equivalent of a rubber stamp, countries have already made the changes that will be shown in the new version.
The advantages of testing for Legionella pneumophila
We know L. pneumophila is currently identified as the most dangerous form of Legionella bacteria.
Those in charge of water sources and engineered water systems should take regular samples of water from various points in the system.
These should then be checked at a qualified laboratory (in the UK this would be a UKAS accredited laboratory) to confirm levels of Legionella pneumophila in the samples.
If the sample proves to be above a safe level, action can be taken to bring those levels back down.
If the sample is proven safe, ongoing monitoring can continue.
Testing for other strains of the bacteria
While other forms of Legionella bacteria can be tested for, it takes longer to do so and costs more as well.
With over 90% of all cases of Legionnaires’ disease stemming from this one form of Legionella bacteria, it makes sense to focus water quality testing on what matters most.
While COVID-19 has grabbed most of the headlines this year, understandably so, it is important to recognise the continued threat that Legionnaires’ disease poses.
With proper steps taken to prevent outbreaks, such as regularly testing water supplies, many outbreaks can be avoided before they even begin.
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