Legionnaires' disease is a severe lung infection caused by the bacterium Legionella pneumophila. It does not spread from person to person; instead, it is transmitted by inhaling contaminated water droplets and aerosols. Common sources include showerheads, hot and cold water systems, cooling towers, spas, whirlpools, and jacuzzis.
Legionnaires' Disease Risk in Turkey
Due to high tourism activity, large water installations, and extensive international travel, Legionnaires' disease is considered a significant public health concern in Turkey. Since 1996, the disease has been monitored within the “Legionnaires' Disease Control Program,” which mandates various preventive measures for high-risk facilities.
Risk Factors
People at increased risk of developing Legionnaires' disease include:
- Being over 50 years old
- Male gender
- Smoking
- Chronic lung disease
- Weakened immune system
- Alcohol dependence
- Underlying medical conditions such as diabetes, cancer, organ transplantation
- Exposure to old or poorly maintained water systems
Environments Where Legionella Thrives
- Hot water tanks and hot water distribution systems
- Cold water systems above 20°C (68°F)
- Cooling towers and evaporative cooling units
- SPA pools, thermal baths, whirlpools
- Decorative fountains and artificial ponds
- Respiratory therapy devices in hospitals
- Dental unit waterlines
- Eye wash stations and fire sprinkler systems
Modes of Transmission
Legionella spreads primarily through two mechanisms:
1. Inhalation of Aerosols
- Fine droplets released from showerheads
- Aerosols dispersed from cooling towers
- Steam generated by spas, whirlpools, and jacuzzis
- Humidifiers and misting devices
2. Aspiration
Accidental inhalation or aspiration of contaminated water into the lungs can also lead to infection.
Common Locations Where Legionella Is Present
- Hotels
- Hospitals
- Shopping malls and restaurants
- Sports and fitness centers
- Campsites
- Factories and industrial facilities
- SPA and thermal centers
- Ships and ventilation systems
Preventive Measures for Facilities
- Assign trained personnel responsible for Legionella risk management
- Clean hot water tanks every 3 months and cold water tanks every 6 months
- Maintain hot water tank temperatures at a minimum of 60°C (140°F)
- Ensure that tap water reaches 50–60°C (122–140°F) within 1 minute
- Eliminate unused pipe sections and dead legs
- Flush taps and showers in unoccupied rooms for at least 3–5 minutes daily
- Regularly descale and disinfect showerheads
- Perform mechanical cleaning of cooling towers at least twice a year
- Disinfect heating and plumbing systems annually
Procedures Before Reopening a Facility
- Increase hot water system temperature to 70°C (158°F) and maintain it for 24 hours
- Flush all taps and showers for 5–10 minutes before use
- Apply system-wide hyperchlorination (minimum 3 ppm)
- Remove, clean, and disinfect showerheads
- Fully drain and disinfect cooling towers
Water Sampling and Monitoring
To effectively control Legionella risk, facilities must conduct monthly water sampling and ensure continuous implementation of appropriate biocide applications.
Conclusion
Legionnaires' disease represents a serious health risk in large facilities such as hotels, hospitals, and SPA centers. Regular system maintenance, temperature monitoring, proper disinfection, and routine water analysis are essential for safeguarding public health and complying with regulatory requirements.
