Legionella, or to give it its full name, legionella pneumophilia, is a deadly strain of bacteria that can breed exponentially within a water supply. When breathed in by a human in water droplets in the air, Legionella bacteria is the direct cause of Legionnaire’s disease, a highly dangerous strain of pneumonia that in the worst cases can cause death or poor health for several years.
Everyone is susceptible to infection of Legionnaire’s disease, although several people such as those over 45 years of age, smokers and heavy drinkers, those with existing respiratory or kidney disease and with impaired immune systems are much more at risk of contracting the disease when exposed to water vapour that houses the bacteria.
The bacteria is commonly found within water-based systems such as rivers or reservoirs in low, less dangerous numbers. Legionella becomes much more dangerous when it is given the chance to grow in a contained water system with a high temperature environment where bacteria can thrive, increasing the number of bacteria present in the water and increasing the risk of someone near to the water contracting the disease. Large buildings, such as hotels, hospitals, museums and office blocks or other areas with complex and large water supply systems are the most at risk from Legionella spreading through the water system.
When Legionella is given the chance to grow, the chance of the bacteria being present in water droplets within the air increases greatly. Direct consumption of water infected with Legionella can also infect a person, leading to Legionnaire’s disease.
Those affected by the disease can expect symptoms closely related to flu including high temperature, fever and chills, coughing, muscle pains and headaches. In the worst cases, Legionella can cause pneumonia, signs of mental confusion and diarrhoea, leading to a significant risk to the person’s life (particular if they are older).
Legionnaire’s disease is non-contagious, but steps must be taken at all times to prevent the spread of the bacteria from affecting other people.