Legionella and Legionnaires’ Disease: Updated FAQs

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In July, 1976, a mysterious illness began to spread among guests, staff of the BEllevue-Stratford Hotel in Philadelphia and among attendees of an American Legion Convention that had been held there. During and then following an American Legion convention at the property, severe respiratory symptoms began appearing: high fever, chest pain, and fatigue.

Within weeks, up to 221 people were symptomatic, and 34 expired from the illness. Physicians and public health officials first thought they were dealing with a traditional form of pneumonia, but standard treatments didn’t work. CDC microbiologists identified the cause in January, 1977 — a previously unknown bacterium coined Legionella pneumophila. Water samples from the hotel’s cooling tower, a device used to cool water for the HVAC system, identified the presence of the bacteria. The hypothesis was that those who had come down with the illness had been exposed to contaminated mists from the cooling tower. This meant that other cooling towers or water systems could be contaminated with the bacteriaand the threat was as real to buildings in Los Angeles as to those in Philadelphia.

The following FAQs provide our response to common questions about Legionnaires’ disease, so-named after the American Legion Convention and the Legionnaires’ who became ill at the convention, and Legionella bacteria. Our aim is to give building owners and managers actionable tips on how to prevent Legionella contamination on their properties and protect their occupants from Legionnaires’ disease.

What is Legionnaires’ disease?

Legionnaires’ disease is a serious respiratory infection caused by the Legionella bacteria. People contract it by inhaling tiny, contaminated water droplets that contain Legionella bacteria. Because building water systems can be a source of exposure, ensuring they’re inspected and maintained properly can prevent costly outbreaks and protect public health.

What is Legionella bacteria, and where is it commonly found?

Legionella bacteria are naturally present in freshwater sources. In a building, however, they can become hazardous when they multiply in hot water tanks, cooling towers, and other water systems. Under certain conditions, Legionella can thrive, grow, and spread through contaminated mist or aerosols, leading to exposure and potential impact on human health.

What are the symptoms of Legionnaires’ disease?

Symptoms include coughing, shortness of breath, fever, muscle aches, and headaches, typically appearing within two weeks of exposure, often within days. Initially, the disease can resemble the flu, but it can quickly progress to severe pneumonia, particularly in older adults or those with weakened immune systems. Prompt medical treatment of Legionnaires’ disease is essential. Early diagnosis can significantly improve recovery outcomes.

Who is most at risk for Legionnaires’ disease?

The risk is highest among older adults, smokers, and people with compromised immune systems or chronic health conditions, such as lung disease. Those in high-risk environments, such as healthcare facilities or nursing homes where building occupants are more likely to have risk factors, are more vulnerable to experiencing an outbreak of Legionnaires’ disease if Legionella amplification is present in their water systems.

What types of buildings are at higher risk for Legionella contamination?

Large multi-story buildings with complex water systems and centralized hot water, such as hospitals, hotels, and office buildings, or facilities that have cooling towers, decorative fountains, or hot tubs, are more at-risk with respect to Legionella. Water can become stagnant in unused pipes, and the loss of residual disinfectant and fluctuating temperatures may support bacterial growth.

What are the potential sources of Legionella in a commercial building?

Legionella can grow in many places, such as cooling towers, hot water tanks, decorative fountains, and humidifiers. Anywhere a plumbing system exists, the threat of Legionella amplification and subsequent human exposure is possible.

What are the recommended prevention measures for Legionella?

Effective prevention includes controlling water temperatures, ensuring adequate residual disinfectant, flushing low-use fixtures, and performing regular maintenance and testing. For high-risk areas or buildings, filtration or supplemental disinfection systems can be considered to keep bacteria levels controlled. Implementing control measures as part of a well-developed water management plan and training your staff on these measures are essential steps to reduce risk.

How often should water systems be tested for Legionella?

Only a few states have regulations that require Legionella testing, and where regulations exist, they typically address sampling only in cooling towers or high-risk settings such as healthcare. For most buildings, sampling frequency is up to the discretion of the water management team and may depend on the building type, system complexity, and types of water systems present. Many buildings with mature Water Management Plans may elect to perform routine proactive Legionella testing anywhere from quarterly to annually. Other buildings may choose to perform testing only in response to suspected illness. Testing for Legionella is the best way to validate that a water management plan is working to control Legionella and provides valuable insights to catch any amplification issues early before they escalate.

What are the potential sources of Legionella in a commercial building?

Regulations vary and are limited, but some states and local jurisdictions require Legionella water management plans, with most requirements geared toward addressing risks in healthcare or cooling towers. Voluntary standards and guidance documents from organizations like ASHRAE and AIHA offer guidance for managing Legionella in water systems. Building owners should familiarize themselves with these guidelines to work toward compliance where practical and reduce health risks.

What is a water management plan, and why is it important?

A water management plan is a structured approach to monitoring and controlling Legionella in water systems. It includes detailed steps for regular inspections, maintenance, and testing to ensure water safety. Implementing a clear plan is essential for preventing Legionella growth, especially in high-risk environments. Staying proactive with a management plan reduces liability and keeps water systems safe.

Are there regulations for Legionella prevention in commercial buildings?

Regulations vary and are limited, but some states and local jurisdictions require Legionella water management plans, with most requirements geared toward addressing risks in healthcare or cooling towers. Voluntary standards and guidance documents from organizations like ASHRAE and AIHA offer guidance for managing Legionella in water systems. Building owners should familiarize themselves with these guidelines to work toward compliance where practical and reduce health risks.

What should a Legionella water management plan include?

A good water management plan should cover system monitoring, maintenance schedules, testing protocols, and corrective actions if Legionella is detected. Staff training on these procedures is key to successful implementation. Regular updates to the plan ensure it reflects current building conditions and any regulatory changes.

What are common methods for Legionella control in water systems?

Maintaining stored hot water temperatures at 140°F (60°C) or above, hot water delivery temperatures at 120°F or above, flushing unused pipes, and ensuring adequate residual disinfectant are examples of standard practices for Legionella control. Filtration systems are also effective in reducing bacterial exposure for end-users, and facilities may consider implementing them in areas considered to be high-risk. Routine maintenance of cooling towers, hot water tanks, and other water system components can help to prevent conditions favorable to Legionella growth.

What should I do if Legionella bacteria is detected in my building?

Immediate action when cases of Legionnaires’ disease are suspected is essential. Sampling should be performed in at-risk water systems to determine whether Legionella amplification is present. Cleaning and disinfection of localized fixtures or components or system-wide disinfection, such as hyperchlorination, may be indicated. Consulting a FACS Legionella specialist can help ensure thorough and effective assessment and remediation where needed. Clear communication with building occupants about actions being taken is also advised to maintain trust and safety.

What are the potential legal implications of a Legionella outbreak?

An outbreak can lead to lawsuits and fines if it’s shown that water systems were poorly managed or maintained. Building owners may face financial and reputational consequences. Documenting preventive actions and adhering to guidelines reduce these risks by demonstrating a commitment to water safety and occupant well-being.

How is Legionnaires’ disease diagnosed and treated?

Diagnosis typically involves a chest X-ray and laboratory tests to identify Legionella bacteria. Treatment requires antibiotics, as the disease does not respond to standard viral treatments. Early treatment is key to recovery, especially for high-risk individuals. Building owners and managers should encourage occupants to seek medical treatment if they exhibit symptoms of Legionnaires’ disease, which is a Centers for Disease Control and Prevention (CDC) reportable illness. Early diagnosis and treatment significantly increases the chances of full recovery.

What steps should be taken if a building occupant or visitor contracts Legionnaires’ disease?

Because Legionnaires’ disease symptoms are similar to other lung illnesses, the first step is for the occupant to seek medical treatment. If the diagnosis is Legionnaires’ disease, the medical provider will notify local health authorities. Most cases of Legionnaires’ disease are sporadic, meaning they are acquired from somewhere in the community but are never linked to a specific water source. If a building occupant is diagnosed with Legionnaires’ disease, it does not mean the building water is the source of their infection, but performing a due diligence assessment of the building is prudent. Begin by reviewing the building water systems to identify areas of potential risk, then develop and implement a sampling plan to evaluate those areas. Sample results and comprehensive risk assessment can guide the implementation of remediation measures as needed. Communicating these steps to occupants reassures them that safety is a top priority. By acting quickly, building managers can ensure that additional cases of illness do not occur.

How does Legionella testing work, and how reliable are the results?

Testing involves sampling water at multiple points in the system and analyzing it for Legionella. Multiple rounds of testing may be needed to identify amplification areas and ensure adequate remediation. Routine testing helps detect issues before they become larger problems. Consulting with a FACS water systems expert helps ensure accuracy and proper follow-up.

How can I keep up to date with guidelines and best practices for Legionella management?

Resources like ASHRAE, AIHA, the CDC, and local health departments provide valuable, up-to-date guidance on Legionella management. Regularly review and adjust your water management plan to reflect best practices.

For help selecting the most effective prevention strategies and to ensure your Legionella water management plan protects your property adequately, be sure to contact FACS by telephone here: 888-711-9998.