Legionella is attacking again and again!

The bacterium lurking in water systems, Legionella, poses a serious health risk based on laboratory measurements. Regular inspections are therefore mandatory, with particular attention to the water systems of baths and industrial facilities. What do the statistics show? Why is Legionella dangerous, how to prevent it from spreading, what tests are worth doing? Laboratory experts will help you find your way around the issue.

The bacterium, which is known and dreaded worldwide and infects with an aerosol formed from water, has already taken several lives in Hungary, and the diseases it causes can still have extremely serious consequences. The WESSLING Knowledge Center has conducted thousands of Legionella measurements, and the aggregation of the data will once again turn our attention to the infamous Legionella in connection with the upcoming tourist season and the periodically closed, now reopening industrial facilities.

Legionella has been detected in more than a quarter of more than a thousand drinking water samples tested by WESSLING in recent years, and has exceeded the warning level in more than 12 percent of the samples. It turned out that Legionella testing should be taken seriously in industrial facilities and factories: according to the data, Legionella was detected in more than a tenth of the samples from the cooling towers, and half of them exceeded the warning level.

Regular testing for Legionella has been mandatory in Hungary since 2016, as the infamous bacterium can pose a serious health risk: Legionella, which multiplies quickly in lukewarm, warm water, can cause serious illness if it escapes into the environment with water vapor and this so-called aerosol is inhaled by humans. The disease it causes, legionellosis, is essentially an atypical pneumonia that can be a fatal respiratory illness in people with a weakened immune system.


Who can be involved?

All built water systems in which the following conditions are met are considered to be at risk for Legionella infection: water with a temperature of 20-50 ° C, the possibility of stagnant water bodies (large-scale systems with uneven or non-uniform flow), formation of a finely divided water spray (aerosol).

The range of facilities involved is enormous, from public baths and spa hotels to warehouses and other industrial facilities with cooling towers to hospitals and social institutions.

The presence and amount of Legionella in the water system can be determined by laboratory water testing. The law requires regular sampling of domestic hot water systems in high-risk facilities. For health and social facilities, commercial accommodation, the Legionella germ count must be determined annually, in wet cooling towers and in public baths (in the case of water-spraying basins warmer than 30 ° C) on a monthly basis. 


What can be done to prevent the spread of Legionella?

Tamás Vadasi, Head of the Food Safety Business Unit of WESSLING Hungary Kft., said that ensuring the flow of water, cleaning and descaling the fittings, and continuous air exchange are extremely important. In the case of buildings that are temporarily out of use, the operation of water systems should therefore be aimed at eliminating and minimizing the above conditions. It is therefore extremely important to carry out microbiological tests on drinking water. In addition to Legionella, in case of drinking water and domestic hot water, microorganisms capable of increasing the growth in stagnant water include Coliform, Escherichia coli, Pseudomonas aeruginosa and Enterococcus.

The risk assessment for Legionella and the associated accredited laboratory tests must be taken very seriously, as this area is regulated by a regulation.


You can find out more about Legionella tests here.

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