A bacterium called legionella can cause severe pneumonia disease called legionnaires. It is commonly found in freshwater sources but rarely causes this illness. But it can cause this disease in water management plans. That is why; it is very important to maintain these big water sources. These water systems are very complex and hence a good place for this bacterium to multiply itself.  Moreover, it can also be found in other water sources such as cooling towers in large buildings, whirlpool spas, heaters, and hot water tanks, decorative fountains and showerheads. A little change in the temperature of the water increases the growth of Legionella. legionella risk assessment should be in place in such buildings water management plans.

A small amount of this bacterium cannot cause illness. If a sufficient amount is present in the water droplets then it can make a person ill. When a person breathes in such air, it directly enters into the lungs to cause pneumonia. However, this illness cannot transfer from person to person.

Who Is at Risk?

Healthy persons with a strong immune system have a low risk of this disease. But a person who has lung disease or older is at high risk. It includes;

  • People who are 50 years of age or older.
  • People who have any kind of chronic disease.
  • Peron with weak immune system.
  • People who certain health conditions like kidney failure, cancer, and diabetes.


Some common symptoms of legionnaires disease are as follows:

  • Shortness of breath
  • Cough
  • Fever
  • Headaches
  • Muscle Aches

Other common symptoms include diarrhea and nausea. However, these signs can take up to 10 days to appear after exposure. If you start to see any of the symptoms then you should see a doctor right away.

How It Can Be Treated?

The doctors can treat this disease with antibiotics. However, some patients need close monitoring to fully recover. This disease can also cause death and lung failure.

How to Prevent This Disease?

A simple way to prevent this disease is by regularly maintaining the water supply of the building. With proper maintenance, the bacterium cannot grow and multiply. Hence it is really important to regularly maintain the water system and disinfect it. If you have decorative fountains in the building then clean them regularly. This bacterium cannot grow in your car air conditioner because it does not use water for cooling. It spreads mostly in large buildings with complex water management plans.

There are many species of it but the most common that causes legionnaires is legionella. In all the previous outbreaks, this species was responsible. That is why; it is important to test the water samples for its presence. There are many tests, but the main test for this species is the most important. Rapid tests are not able to provide accurate results. A regular test for Legionella pneumophila is a way to make sure the water system is effective. Moreover, you need consistent data about the location of the bacteria to respond.


Founder of Paisley.org.uk in 1998 and constantly strives to change peoples attitudes to the town, Brian is a self described Paisley Digital Champion who promotes Paisley via any means necessary. You can also follow me on X