What Legionnaires' disease is and typical symptoms
Introduction
Legionellosis is a collective term for diseases caused by legionella bacteria including the most serious Legionnaires' disease, as well as the similar but less serious conditions of Pontiac fever and Lochgoilhead fever.
Legionnaires' disease is a potentially fatal form of pneumonia and everyone is susceptible to infection. The risk increases with age and some people are at higher risk including:
- people over 45 years of age
- smokers and heavy drinkers
- people suffering from chronic respiratory or kidney disease
- diabetes, lung and heart disease
- anyone with an impaired immune system
If conditions are favourable, the bacteria may grow, increasing the risks of Legionnaires' disease. It is therefore important to control the risks by introducing appropriate measures outlined in Legionnaires' disease - the control of legionella bacteria in water systems (L8).
Where it comes from
Legionella bacteria are widespread in natural water systems, such as rivers and ponds. However, the conditions are rarely right for people to catch the disease from these sources.
Outbreaks of the illness occur from exposure to legionella growing in purpose-built systems where water is maintained at a temperature high enough to encourage growth, for example cooling towers, evaporative condensers, hot and cold water systems and spa pools used in all sorts of premises (work and domestic).
How people get it
People contract Legionnaires' disease by inhaling small droplets of water (aerosols), suspended in the air, containing the bacteria. Certain conditions increase the risk from legionella if:
- the water temperature in all or some parts of the system may be between 20-45 °C, which is suitable for growth
- it is possible for breathable water droplets to be created and dispersed, for example aerosol created by a cooling tower, or water outlets
- water is stored and/or recirculated
- there are deposits that can support bacterial growth providing a source of nutrients for the organism, such as rust, sludge, scale, organic matter and biofilms
Cases of Legionnaires' disease are often the result of infections caught in the UK, but a number of cases occur abroad. There is useful advice on travel from European Working Group for Legionella Infections.
Symptoms and treatment
The initial symptoms of Legionnaires' disease are similar to those of flu:
- high temperature, feverishness and chills
- cough
- muscle pains
- headache
It can also lead on to more serious symptoms such as:
- pneumonia
- diarrhoea
- signs of mental confusion
Legionnaires' disease is not known to spread from person to person.
How it is treated
The illness is treated with an antibiotic called erythromycin or a similar antibiotic.
What to do if you have symptoms
If you develop the above symptoms and you are worried that it might be Legionnaires' disease, see a doctor.
It is not always easy to diagnose because it is similar to the flu. A urine or blood test will be helpful in deciding whether an illness is Legionnaires' disease or not. When doctors are aware that the illness is present in the local community, they have a much better chance of diagnosing it earlier.
If you suspect that your illness is a consequence of your work then you should report this to your manager. You should also tell your health and safety representative and occupational health department, if you have one. There is a legal requirement for employers to report cases of Legionnaires' disease, which may have been acquired at their premises, to the Health and Safety Executive.