Legionnaires’ disease is a type of severe pneumonia caused by the legionella bacteria.
It is one of several diseases going under the name legionellosis, the others being Pontiac fever and Lochgoilhead fever. Of these diseases, legionnaires’ disease is the most serious. It can be fatal.
How Do You Get Legionnaires’ Disease?
You get legionnaires’ disease by inhaling tiny droplets, or aerosol spray, of water that is in the air. The disease then goes on to infect the lungs.
The name of the disease comes from its first identified outbreak. This occurred at an American Legion convention in Philadelphia in 1976. There were 182 cases, resulting in 29 deaths.
Investigators discovered that the cause of the outbreak was a cooling tower in the hotel where the convention was taking place. People were inhaling droplets from the cooling tower. The bacteria identified at the site were named legionella.
In fact, legionella bacteria have probably existed for many millions of years as a natural part of the environment. Legionella is found in natural water sources such as lakes and streams. But in these natural environments, the bacteria occurs in amounts that aren’t harmful to humans.
In man-made water systems, the bacteria can thrive, however. Where this occurs, there is an increased risk of legionnaires’ disease.
To catch legionnaires’ disease, these conditions will apply:
- Legionella must be in the water system
- The water in the system is stagnant or slow-moving
- There is an adequate food source for the bacteria
- The temperature range of the water in the system is 20–45°C
- It emits water droplets or aerosols
- There are people close enough to inhale these emissions.
What are the Early Signs of Legionnaires’ Disease?
Early symptoms of legionnaires’ disease are flu-like, including headaches, aching muscles, a dry cough, tight chest, sickness and diarrhoea.
With the onset of a high fever, people may become confused or delirious.
One reason why legionella is so effective at attacking the body is that its optimum temperature for growth is 37°C, which is the same as normal human body temperature.
With early symptoms being similar to flu, when should you suspect legionella is the cause?
The disease is not spread from person to person. To catch it, you must inhale the bacteria from a contaminated water source. If you have any reason to think this is the cause of your illness, you should seek immediate medical help.
The NHS advises you to phone 111 for advice if:
- You cannot breathe properly
- You have got chest pain
- You feel you have got severe flu symptoms.
Can You Test for Legionnaires’ Disease?
Legionnaires’ disease is not always straightforward to diagnose. This is why it is essential to seek medical advice if you suspect you have it.
You may need to then visit your GP. A blood or urine test for legionella antigens will help the doctor decide whether you have the disease.
If there is evidence of more people having these symptoms in the local area or community, then this can support an earlier diagnosis.
Where you think you may have contracted legionnaires’ disease at work, you should notify your manager and your health and safety representative.
Employers are required by law to report legionnaires’ disease outbreaks to the Health and Safety Executive (HSE).
Any subsequent testing for the legionella bacteria in the workplace or other water systems should be compliant with BS 7592.
How Serious is Legionnaires’ Disease?
Legionnaires’ disease is a life-threatening illness and it requires rapid treatment. The infection can seriously damage lung function, preventing blood from reaching vital organs in the body – in some cases, people with the disease get sepsis.
To date, the largest outbreak in the UK was in Barrow-in-Furness in 2002. In fact, this is one of the worst recorded outbreaks of the disease. Seven people died, and there were a reported 172 cases.
Investigations identified the source of the outbreak as a faulty air conditioning unit in a council-run leisure facility. The unit was emitting contaminated aerosols into the air in an alleyway that people walked through regularly.
Barrow Borough Council became the first public body in the UK to face corporate manslaughter charges.
Around 300 cases of legionnaires’ disease a year are reported in England in Wales. Research indicates that substantial numbers of pneumonia cases in European hospitals may actually be caused by the legionella bacteria.
We may be underestimating the total number of legionnaires’ disease cases year on year simply because currently treating patients is cheaper than testing them. If someone goes into the hospital with symptoms indicating pneumonia, they’ll be treated with antibiotics. Doctors are only likely to test them for legionella if they suspect there’s been an outbreak.
The mortality rate for legionnaires’ disease is 10–20%, and there are reasons why legionnaires’ disease is often seen as a hidden killer.
Who is Most at Risk?
Certain groups are more at risk from legionnaires’ disease.
- People aged 45 and over
- People with weakened immune systems
- People with cancer, kidney disease or respiratory illnesses
- Smokers and heavy drinkers.
Men are more likely to get legionnaires’ disease because they have a greater lung capacity than women.
What is the Treatment for Legionnaires’ Disease?
In hospital, treatment for legionnaires’ disease can involve:
- Antibiotics administered intravenously (given directly into the vein)
- Oxygen provided through a nasal tube or via face mask
- Use of a ventilator to assist with breathing.
Antibiotics are the major form of treatment, and when patients start to feel better, they may be sent home with a course of antibiotic tablets they must continue to take.
Most people treated in time should go on to make a full recovery.
The recovery time for legionnaires’ disease will depend on the individual patient, but most people begin to respond to treatment within three to five days.
They may have to take antibiotic tablets for several weeks after being discharged from hospital, however. For some people, there can be long-term effects and implications for their health.
What are the Long-term Health Effects of Legionnaires’ Disease?
Some legionnaires’ disease sufferers are left with severe disabilities, such as blindness, deafness or loss of use of their limbs due to having gone into a coma.
There can be other long-term complications arising from how breathing in the legionella has affected people’s lungs.
The severity of the disease can depend on the general health of the person who gets it.
Elderly people or people with underlying health conditions may find recovery longer and more challenging. In some cases, the effect will be life-changing or life-limiting.
Is Legionnaires’ Disease Contagious?
You cannot pass legionnaires’ disease from person to person.
You catch the disease from inhaling small droplets of contaminated water, not from contact with other people who have the condition.
Sources of legionella can include:
- Showers and taps
- Plumbing systems
- Cooling systems and cooling towers
- Hot and cold water systems
- Spa baths, hot tubs, thermal spas and pools
The bacteria can thrive in large, complex plumbing systems. This is one of the reasons why there are hospital outbreaks, and why controlling legionella risk is essential in large offices and other workplaces.
Legionella also likes warm temperatures, which is why people can end up getting legionnaires’ disease when they travel abroad.
How Do You Prevent Legionnaires’ Disease?
Essentially, the most important precaution against legionnaires’ disease is to monitor, manage and test water systems for the presence of legionella.
Legionella is the source and cause of legionnaires’ disease.
There are various methods for controlling legionella in water systems. These include:
- Managing water temperatures, ensuring hot stored water is above 60°C and hot water that the system distributes is above 50°C
- Storing cold water in the system below 20°C
- Using a recommended and certified water treatment to disinfect pipework, remove biofilm and kill legionella.
Water Treatment for Legionella Control
Biofilm is a thin film of algae that builds up in water systems and plumbing. It helps to create the conditions where legionella bacteria can grow and multiply.
To control legionella, you must keep water distribution systems clean and prevent biofilm build-up.
Oxyl-Pro is a hydrogen peroxide-based disinfectant that works to remove biofilm and is highly effective against legionella.
If you want to prevent legionnaire’s disease, you need to control and kill legionella.