Legionnaires’ disease is a serious form of pneumonia caused by legionella bacteria. People catch it by breathing in tiny droplets of contaminated water. It cannot be passed from person to person, and it is preventable when water systems are properly managed.
Symptoms
According to the Health and Safety Authority, the first signs are a high temperature, fever, chills, muscle pains and headaches. A dry cough and breathing difficulties may follow, leading to pneumonia. Some people also have diarrhoea, vomiting or confusion. Symptoms usually develop 2 to 10 days after infection.
Anyone with these symptoms should contact their GP, and mention any recent hotel stay, spa visit or workplace exposure to water spray. The illness is treated with antibiotics, and early treatment matters.
How people catch it
Legionella lives naturally in rivers and lakes in low numbers. It becomes a danger when it gets into a building’s water system and multiplies. The bacteria grow best in water between 20°C and 45°C, especially where water stands still and there is scale, sediment or slime to feed on. People are exposed when that water is turned into spray by:
- showers and spray taps
- spa pools and hot tubs
- cooling towers
- humidifiers, fountains and misting systems
- vehicle washes and hoses
Drinking contaminated water is not the usual route. The risk comes from breathing the droplets in.
Who is most at risk
The Health and Safety Authority notes that the risk is higher for men than women, for people aged over 45, for smokers and for anyone whose immune system is impaired. That is why nursing homes, hospitals and hotels with older guests need tighter controls.
How it is prevented
- Assess the risk: a legionella risk assessment finds where bacteria could grow in your system.
- Control temperature: keep cold water below 20°C and store hot water at 60°C or above.
- Keep water moving: flush outlets that are rarely used.
- Keep the system clean: tanks, shower heads and hoses.
- Check and record: temperatures, flushing and cleaning, with sampling where the assessment calls for it.
What employers should do
Employers have a duty to assess and control risks to health at work. A written legionella risk assessment, reviewed at least once a year, is the starting point. Read six common legionella risks in buildings to see what an assessor looks for.
Safer Solutions provides legionella risk assessments and sampling across Ireland. Call 086 275 9728, email info@safersolutions.ie or request a quote.