What is Legionnaires’ disease?
Where are legionellae organisms found?
What are the usual symptoms of legionellosis?
What should I do if I think I have been exposed to the bacterium and I feel ill?
Do employers/people who let out business premises have duties?
Where can I get more information?
What is Legionnaires’ disease?
Legionnaires’ disease is a bacterial disease, which may cause pneumonia. The majority of cases are single (isolated) but outbreaks can occur. An outbreak in Philadelphia in 1976, largely among people attending a state convention of the American Legion, led to the name legionnaires’ disease. The disease can also be referred to as legionellosis.
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Is this a new disease?
No. While the bacterium was only recently identified, cases have been confirmed as far back as 1947 and cases probably occurred before that date.
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How widespread is it?
It is a relatively rare disease. In England and Wales about 150-250 cases are reported each year. There were just four cases per million people in Europe during 1998.
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Where are legionellae organisms found?
Legionellae are widely distributed in the environment. They have been found in ponds, hot and cold water systems and water in air conditioning cooling towers.
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How is legionellosis spread?
The disease is spread through the air from a water source. To date, all studies have shown that person-to-person spread does not occur. Breathing in aerosols (tiny water droplets suspended in air) from contaminated water systems is the most likely route for the transmission of infection. However, the circumstances in which this can happen appear to be very rare.
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Who gets legionellosis?
The vast majority of people who are exposed to the bacterium do not develop the disease. People of all ages can get legionellosis but it mainly affects older adults. People are at an increased risk of contracting the disease if they are over 40, or they smoke or their immune system is compromised. Males are more likely to contract the disease than females.
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What are the usual symptoms of legionellosis?
The early symptoms of legionellosis may be ‘flu-like’ with muscle aches, headaches, tiredness and a dry cough followed by a fever, chills and occasionally diarrhoea. Pneumonia may develop.
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Can it be fatal?
The mortality rate is 10-12% but in immuno-suppressed patients or those with underlying disease this figure may be higher.
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When do the symptoms occur?
If someone exposed to the bacterium is going to develop the disease, the symptoms will usually occur 3 to 6 days after exposure. Symptoms will sometimes occur as soon as 2 days after exposure, or as late as 10 days after exposure. In very rare cases, the symptoms could occur as early as one day after exposure or as late as 14 days after exposure.
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What should I do if I think I have been exposed to the bacterium and I feel ill?
Contact your general practitioner for advice. Tell them that you may have been exposed, when and where that could have happened and what your symptoms are.
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What is the treatment?
Antibiotics are effective at treating the disease.
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Do employers/people who let out business premises have duties?
Yes, but who is responsible will depend upon the particular circumstances. Where a water system serves several businesses at the same premises, the building owner or managing agent will usually be responsible. Where the system only serves one business, that business is likely to be responsible.
As a minimum, the responsible person or organisation should have:
A written assessment of the risks (reviewed regularly)
A documented system that sets out how the risks are to be controlled.
A document that says who is responsible for managing the risks, and
Records that show that proper precautions have been applied.
Registered any water-based cooling towers/evaporative condensers with their Local Authority.
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Where can I get more information?
The Health and Safety Executive have produced a free leaflet that provides further guidance on the control of the disease at work premises. A copy of the leaflet can be downloaded from their website, link on the right side of this page under 'External links'.
There is also an Approved Code of Practice “Legionnaires’ disease: the control of legionella bacteria in water systems”, available from HSE books.
You can also visit the NHS choices website, available on this page under 'External links'.
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How can I contact you for further information?
Email: healthandsafety@hounslow.gov.uk
Tel: 020 8583 5555
Environmental Safety Section
Environment Department
London Borough of Hounslow
Civic Centre
Lampton Road
Hounslow
TW3 4DN