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When businesses finally get to re-open their doors, another health issue is a real risk – Legionnaires disease.

What is Legionnaires disease?

Legionella bacteria are the cause of legionellosis, better known as Legionnaires Disease.  Legionnaires disease is a potentially fatal form of pneumonia. It can be contracted when a person breathes in contaminated tiny water droplets. Anyone can contract Legionnaires disease, but the elderly, smokers, alcoholics and those with cancer, diabetes or chronic respiratory or kidney disease are at more risk. In February 2020, a 5 star hotel in Kerry was sued after a guest contracted the disease whilst using the spa facilities.

How can Legionella end up in the water supply?

Legionella bacteria are found in low numbers in lakes, rivers and ground water. As a result, it is difficult to prevent Legionella bacteria entering man-made water systems. In low numbers the bacteria are generally considered harmless. With the correct conditions, for example, warm water, the presence of micro-organisms and nutrients in the water or materials such as rust, the bacteria can grow and multiply to high levels which increase the risk of contamination. They are likely to grow where water has become stagnant or a where there is a low water flow. With a lot of business closed over the last number of weeks this could be ideal conditions for legionella to grow. Systems and equipment with reduced or no use over a period of time can be at risk.

 What businesses could be affected?

Every business needs to know about Legionella as ignorance could lead to potential deaths or serious illness. At particular risk are:

·        Warm/ stagnant water supply

·        Hot and cold water systems including taps and showers in public and private buildings

·        Air conditioning units

·        Cooling towers

·        Spa and swimming pools

·        Water fountains,

·        Sprinkler systems

·        Nebulisers.

How can you help prevent its occurrence?

For optimum growth of the bacteria, a temperature of 20 – 45°C is required. Taking this into account you should ensure the cold water system is operating at a temp of less than 20°C, and the hot water system is always above 45°C. Temperatures > 60°C kill the bacteria.

·        Prevent favourable temperatures and conditions for bacterial growth. Keep out of 20-45 °C temp range.

·        Prevent water stagnation – If you have access to your business run all taps, showers, flush toilets etc on a weekly basis.

·        Flush hot and cold water through all points of use to remove stagnant water. Care should be taken to minimize splashing and aerosol generation during flushing.

 What to do prior to re-opening your premises?

If your water systems have been out of use for a significant time, in a lot of cases, they cannot simply be used straight away. The system may require thorough flushing, cleaning and disinfection prior to return to use. Risk assessment review and water testing should also be considered as part of the recommissioning plan. The services of a competent person may be required to provide further advice.

To ensure your water is free from Legionella you can take a water sample and send it to a lab for testing. This will confirm your water is safe and free from the bacteria.

I hope this article has given you some useful information in relation to Legionella. If you would like to find out more, check out the links below.

https://www.hpsc.ie/a-z/respiratory/legionellosis/guidance/nationalguidelinesforthecontroloflegionellosisinireland/Chapter%205%20Legionella%20Prevention%20and%20Control.pdf

https://www.hsa.ie/eng/Publications_and_Forms/Publications/Chemical_and_Hazardous_Substances/Legionaires_Disease.pdf

https://www.escmid.org/fileadmin/src/media/PDFs/3Research_Projects/ESGLI/COVId_buidling_water_system_guidance_27_3_20_v4_DS_pk.pdf

https://www.ecdc.europa.eu/sites/portal/files/documents/Legionella%20GuidelinesFinal%20updated%20for%20ECDC%20corrections.pdf

https://www.who.int/news-room/fact-sheets/detail/legionellosis