Legionnaires Disease is a relatively rare form of Pneumonia which can be very debilitating, difficult to treat and can be fatal in up to 15% of cases.
The disease is caused by the bacterium Legionella pneumophila. This bacteria is the most common cause of the Legionnaires Disease cases worldwide. It occurs naturally in the environment in water sources/systems.
How do you catch Legionnaire's Disease?
The Legionella bacteria have to be inhaled deep into the lungs. Usually this requires a source of small water droplets or aerosol such as may be found in Cooling Tower drift, showers, spray taps etc.
Spread of infection person to person has not been noted.
Several risk factors are significant for possibility of infection.
- A water source with a high Legionella bacteria count
- A means of creating an aerosol that can be breathed in
- A person over 45 years of age
- A person with a low tolerance to infection
- Poorly maintained water distribution systems
- Stagnant water
However the risk of infection is quite low - around 5% of those exposed.
The disease often gives flu-like symptoms including a cough (usually dry), fevers, confusion, bad headache, diarrhoea and vomiting.
Symptoms usually occur 2-10 days after exposure. However, some cases have displayed symptoms up to 3 weeks after exposure.
Diagnosis is usually determined by urine antigen tests.
Advice on the disease and control measures
- Oldham Council Health and Safety Team, phone: 0161 770 2244
- Health and Safety Executive
- Health Protection Agency
- British Lung Foundation
Preventing Legionella pneumophila occurring in water systems
Ensure that all water pipes in a water system are insulated properly so that there is no transfer of heat. This will ensure that hot water is kept at 600C and cold water is kept at approximately 200C, temperatures at which the bacteria growth is limited.
If water is held in storage tanks for any period of time, regular disinfection of the system is recommended to discourage bacteria growth. Checks should also be made to ensure that there is no sediment in the tanks and that they are enclosed so that foreign bodies do not fall in.
All water pipe runs should be kept as short as possible and all dead legs or unnecessary bends, etc. should be removed.
Studies have indicated that copper pipework and storage vessels discourage the growth of the bacterium.
Under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992 all cooling towers and evaporative condensers must be registered with the relevant Local Authority for the area in which they are based.
The Health and Safety Team at Chadderton Town Hall are responsible for maintaining a register of these appliances.
- Cooling towers - Registration
There is also a requirement under the Control of Substances Hazardous to Health Regulations 2002 for the persons having responsibility for these appliance to undertake a risk assessment of its condition and to put in place an effective Legionella management system.
The Council's role in controlling Legionella pneumophila
Local Authorities work in conjunction with the Health Protection Agency, and sometimes the Health and Safety Executive, when cases of Legionnaires Disease are suspected or confirmed.
They are responsible for ensuring that a Patient Case Questionnaire is completed within 24 hours of notification by the Health Protection Agency. The purpose of which is to try and ascertain the patients contact with any possible sources in the two weeks prior to the onset of symptoms. Where appropriate further history may be taken for approximately one month before onset. An investigation will then be undertaken to try and isolate a source so that further infection does not occur.