Legionella is a genus of bacteria that can cause Legionnaires’ disease, a serious and potentially life-threatening form of pneumonia. The bacteria are found in natural and man-made water systems, including hot tubs, cooling towers, hot water tanks and all kinds of plumbing systems. People get infected by inhaling contaminated aerosols or by aspiring contaminated with Legionella, water.
In this article, we will discuss the characteristics of Legionella, the symptoms and diagnosis of Legionnaires’ disease, and measures that can be taken to prevent infection.
Characteristics of Legionella
Legionella is a Gram-negative bacterium that is aerobic, which means it needs oxygen to survive. It can multiply at temperatures between 20-50°C. It is resistant to many disinfectants, including common levels of chlorination, making it difficult to control in water systems.
Symptoms of Legionnaires’ disease
Legionnaires’ disease is a form of pneumonia that can cause fever, cough, shortness of breath, muscle aches, fatigue, headaches, confusion and lethargy. Symptoms usually appear 2-10 days after exposure to the bacteria and the severity can range from mild to severe. In the most severe cases, the disease can rapidly progress to acute respiratory failure, septic shock and multiple organ failure, which can be fatal. Mortality is estimated at 10-15% while, for those who survive, recovery may require months rather than weeks.
Diagnosis of Legionnaires’ disease
The diagnosis of Legionnaires’ disease is based on clinical symptoms, chest X-ray findings and laboratory tests. Blood tests can detect the presence of Legionella antibodies, while urine tests can detect a specific antigen produced by the bacteria. Culture tests are also used but take time.
Preventing Legionella infection
Preventing Legionella infection requires a combination of bacterial control measures and measures to reduce human exposure, especially in populations which are considered more vulnerable. Here are some key preventive measures which can be taken:
- Water System Maintenance: Regularly clean and disinfect water systems, including hot tubs, cooling towers, and plumbing systems.
- Water Temperature Control: Maintain water temperatures above 60°C in hot water tanks and below 20°C in cold water storage tanks.
- Avoid Stagnant Water: Ensure that water systems are designed to prevent stagnation and promote water flow.
- Inform and train: On every site, those responsible for maintaining water systems should be properly trained to identify, assess, and manage Legionella bacteria risks.
- Laboratory sampling and testing of water systems: Regularly check the levels of Legionella bacteria in water systems and take corrective action when necessary.
Conclusion
Legionella is a common bacterium that can cause Legionnaires’ disease, a serious form of pneumonia. The bacteria are found in natural and man-made water systems and are resistant to many disinfectants. Preventing Legionella infection requires a combination of strategies that target the source of bacteria and population exposure to it. By properly maintaining water systems, controlling water temperature, avoiding stagnant water, training those in charge, and by regularly sampling and testing, we can reduce the risk of Legionnaires’ disease and protect public health.
