What is Legionnaires disease?
How do you catch Legionnaires' disease?
You become infected by breathing in water droplets such as an aerosol which contain the legionella bacteria, that’s why we carry out legionella testing to find out if the water is contaminated. There are many different families (species) of legionella, only a few of these make us ill.
Which Legionella bacteria are dangerous?
There are about 50 families (species) of legionella, such as:
- Legionella londiniensis
- Legionella longbeachae
- Legionella lytica
- Legionella maceachernii
- Legionella micdadei
- Legionella moravica
- Legionella nautarum
- Legionella oakridgensis
- Legionella parisiensis
- Legionella pneumophila
The most pathogenic is Legionella pneumophila species. This family (species) has 14 main family members (called serogroups or serotypes) which are simply numbered from 1 up to 14.
It is Legionella pneumophila Serogroup 1 which is responsible for over 90% of the cases of Legionnaires’ Disease.
Several of the ‘other’ species of Legionella can cause fevers but don’t develop into pneumonia.
How do Legionella bacteria get into our water supplies?
Legionella is a natural bacteria found in ponds, streams, rivers and reservoirs. Then, when we take water from these sources for our mains ‘drinking’ water, small numbers survive the disinfection process. At these low levels, the bacteria poses no risk.
When does Legionella bacteria become dangerous?
The bacteria requires a temperature range 20°C – 45°C in order to multiply. At home or work, if either our cold water gets warm or our hot water is too cool, then the legionella bacteria can quickly proliferate.
Given the right temperature and conditions, legionella bacteria can multiply from 10 cfu’s (colony forming units) to 10,000 in just a few days.
When the water is contaminated with these high numbers of Legionella, there is a real risk of people contracting the disease.
What are the symptoms of Legionnaires' disease?
The symptoms of Legionnaires’ disease can begin any time from two days to two weeks after exposure to the initial infection, most however begin after 6-7 days.
For the first two days, you’ll experience just mild headaches and muscle pain. After that the symptoms become more severe and include:
- Fever, sometimes a temperature of 38°C or above
- Severe muscle pains
- Changes to your mental state, such as confusion
As the bacteria begin to infect your lungs, you may also experience:
- A persistent cough, which is usually dry at first but as the infection develops you may start coughing up mucus
- Shortness of breath
- Chest pains
The symptoms of Legionnaires’ disease are similar to those of the flu and this is the reason it is often not diagnosed.
Who is MOST at risk of contracting legionnaires disease?
The risk of infection is based on two factors, the concentration of legionella entering our lungs and the resistance of the individual. ‘At Risk’ people are those who are immunocompromised either because of illness (e.g., cancer) or medical treatment (e.g., chemotherapy). They are at a much higher risk because they can be infected by relatively low legionella counts. HIV-infected patients, for example, have a 40-fold increased risk; organ transplant recipients have a 200-fold increased risk. Smokers, persons over 65 years of age, and heavy drinkers also have a higher risk as does anyone with lung impairment.
Is Legionnaires' disease fatal?
If you are young, fit, diagnosed early and receive treatment, then fatalities are less common.
If you are elderly, already in poor health or suffer from a lung disorder then the risk of fatality rises sharply.
The overall death rate following infection is 12%.
How is Legionnaires' disease diagnosed?
The bacteria can be cultured from blood or sputum samples but this takes many days. Most hospitals instead analyse for antibodies in the blood or perform an antigen test on the patient’s urine, these give a legionella test result in 24 hours.
Is there treatment for Legionnaires' disease?
Yes, antibiotics are used to fight the infection. Treatment should be started as soon as Legionnaire’s disease is suspected, without waiting for confirmation by laboratory test.
Can Legionnaires' disease be passed from person to person?
You cannot catch Legionnaires’ disease from an infected person.
Is there a law which states Legionella testing is mandatory?
If you don’t look after your water and someone becomes ill, prosecutions would be pursued under the Health and Safety at Work regulations or the Control of Substances Hazardous to Health Regulations.
Most companies carry out regular legionella testing to confirm that their maintenance regimes are working.
CQC often insist that sites such as Cares Homes undertake regular testing.
Why do some companies say a test for Legionella is always compulsory?
This is sometimes called an L8 Risk Assessment or a Legionella Risk Assessment. Unfortunately some legionella testing companies do say the laboratory tests are compulsory.
The HSE does, however, recommend legionella testing in the following circumstances:
- At least every 3 months for cooling towers
- In water systems treated with biocides where the storage/distribution temperatures have been deliberately reduced.
- In systems where control levels of the treatment regime (eg temperature or biocide levels) are not being consistently achieved.
- When an outbreak is suspected or has been identified.
- Specific hospital wards with ‘at risk’ patients – eg those immunologically compromised.
What's a Legionella risk assessment?
This is a detailed report on the water systems within a building, this risk assessment will:
- Identify and assess sources of risk – this includes checking whether conditions are present which will encourage bacteria to multiply, eg is the water temperature between 20°-45°C?
- Determine if there is a means of creating and disseminating breathable droplets, eg the aerosol created by a shower or cooling tower.
- Recognise if there are susceptible people who may be exposed to the contaminated aerosols.
- Prepare a scheme for preventing or controlling the risk.
From this report, those who have responsibility for the building will be able to:
- Implement, manage and monitor precautions – if control measures are to remain effective, then regular monitoring of the systems and the control measures is essential. Monitoring of general bacterial numbers can indicate whether microbiological control is being achieved. Sampling for legionella is another means of checking that a system is under control.
- Keep records of the precautions.
- Appoint a person to be managerially responsible.
Is it difficult to test for legionella in water?
Not at all, AquaCert send you sterile bottles which you simply fill with water. We’ll arrange and pay for a courier to pick up the filled bottles and transport them to the laboratory for testing then send you the results as soon as they are available.
We’ll advise you on where to take the water samples from and how many legionella tests are required, we’ll also interpret the analysis and provide recommendations for any adverse results.
Would you like more information about Legionella & Water Testing?