How to prevent Legionnaires’ disease in the workplace?

Legionella pneumophila is a bacterium that occurs naturally and causes legionellosis, a severe respiratory disease that affects the lungs and airways. This bacterium in aerosol form (fine liquid droplets) can cause infection in the lungs after entering the body via the nose or mouth.

Legionella bacteria are frequently found in freshwater, such as lakes, ponds, puddles and even mud. It thrives at water temperatures between 25 and 45°C. You and your workers are at risk of inhaling these bacteria when using showers, taps, humidifiers and garden hoses. People are also at risk of contracting the disease from the use of spas and jacuzzis, from cooling towers, car wash systems, and water fountains. The period between exposure and the first symptoms varies from 2 to 10 days. The bacteria are not contagious to others.

Certain groups of people, such as the elderly, or sick employees, are at an increased risk. In general, Legionnaires' disease affects more men than women, and people over the age of 65 as well as smokers, diabetics, and people who consume alcohol are more susceptible to infection. Those who work in hotels, hospitals, aged care facilities, swimming pool centres or any other sports facilities are also at a higher risk. 

There are two forms of legionellosis. The less severe form – also called Pontiac fever – causes influenza-like symptoms. The severe form is called Legionnaires' disease (named after the infamous outbreak) and causes a serious type of pneumonia with the following symptoms:

• muscle aches
• fever
• diarrhoea and nausea
• shortness of breath

People who are diagnosed with Legionnaires' disease must receive prompt treatment with antibiotics. Late diagnosis or failed treatment can lead to long-term illness and even death. Legionnaires' disease is fatal in 5 to 15% of cases. 

To prevent the growth of Legionella bacteria in water, you will need to conduct an in-depth risk assessment of your installation. Some quick tips:

• Regularly check hot and cold water temperatures. Take samples at regular intervals at high-risk locations or whenever the ideal temperature is exceeded. Legionnaires' disease bacteria start growing in water temperatures as low as 20°C;
• Draw up an inventory of all pipework, from source to destination;
• Ensure that all water lines are properly insulated;
• Make sure water can easily flow through pipes and installations;
• Develop a management plan that meets all legal requirements as laid out in the code of law and in the Flemish decree on Legionella and Legionnaires' disease.