What is Legionnaires disease?
Legionnaires disease is a potentially fatal form of pneumonia which can affect anybody, but
which principally affects those who are susceptible because of age, illness,
immunosuppression, etc. It is caused by the bacterium Legionella pneumophila and related
bacteria. Legionella bacteria are common and can be found naturally in environmental water sources such as rivers, lakes and reservoirs, usually in low numbers. Legionella can survive under a wide variety of environmental conditions and have been found in water at
temperatures between 60C and 60°C. Water temperatures in the range 20°C to 45°C seem
to favour growth. The organisms do not appear to multiply below 20°C and will not survive
above 60°C. The organisms may, however, remain dormant in cool water and multiply only
when water temperatures reach a suitable level. Temperatures may also influence virulence; Legionella bacteria held at 37°C have greater virulence than the same Legionella bacteria kept at a temperature below 25°C. Legionella bacteria also require a supply of nutrients to multiply.
Sources include commonly encountered organisms with water systems, such as algae, amoebae and other bacteria. The presence of sediment, sludge, scale and other materials within the system together with biofilms play an important role in harbouring and providing favourable conditions in which the Legionella bacteria may grow. A biofilm is a thin layer of micro-organism which form a slime on surfaces which are in contact with water. Sludge, scale and biofilms can protect Legionella bacteria from temperatures and concentrations of biocide that would otherwise kill or inhibit these organisms if they were freely suspended in water.
Symptoms
The symptoms are very similar to those of the flu: High temperature and chills, Cough, muscle pains, headache and leading on to pneumonia, diarrhoea and signs of mental confusion.
Legionnaires cannot be passed from person to person. As it is similar to the flu it is not easy to diagnose, and this often requires the taking of a blood or urine sample. If you suspect, you have the illness due to your work then this must be reported at the earliest opportunity to your Line Manager as if confirmed will be reportable to the Health and Safety Executive.
Legislation, standards, guidance and codes of practice
An approved Code of Practice and Guidance L8 (ACOP) “The Control of Legionella Bacteria in Water Systems” became effective on 8 January 2001 and employers (and others as defined) are expected to follow the ACOP guidance in controlling Legionellosis in all circumstances where the Health and Safety at Work Act 1974 (HSW) applies. The ACOP provides practical guidance for compliance with certain provisions under HSW and the Control of Substances Hazardous to Health Regulations (COSHH) 2002 (as amended).
In addition to the ACOP a number of other sources of legislation, guidance, codes of practice, etc. are available and are listed below:
- Control of Substances Hazardous to Health Regulations 2002
- Cold Water Services Water Supply (Water Fittings) Regulations 1999
- “Safe” Hot Water and Surface Temperatures – Health Guidance Note 1998
Operational policy
In order to minimise the risk of a Legionella outbreak the following procedures are in place –
- Shower heads and the Jacuzzi bath are disinfected and flushed on a monthly basis by the housekeeping team. The Staff member carrying out the cleaning records and signs for this on the fortnightly spreadsheet in the laundry room.
- On a weekly basis as part of the housekeeping cleaning schedule water dispenser drip trays are emptied and cleaned through the dishwasher.
- In order to protect guests from the risk of burns all water outlets which are accessible to guests have their temperature controlled by temperature control valves. Water temperatures are checked regularly at various outlets to ensure the water temperature is not hot enough to scald guests and within the recommended temperature range to reduce the risk of a legionella outbreak. On an annual basis all outlets will have been temperature checked a minimum of three times.
Suspected outbreak
If there is a suspected outbreak or test results from testing show the presence of legionella in the system, then the Head of Services will inform the CEO who will report it to the HSE and Local Authorities. Leuchie House will work in conjunction with all involved in order to ensure any outbreak is contained and all necessary steps are taken to prevent a further reoccurrence.
Reviewed – Feb 2025