Legionella and Legionnaires Disease

In 1976, over two hundred delegates attending an American Legion convention in Philadelphia became ill with a respiratory disease, subsequently named Legionnaires’ disease. The bacteria that was responsible for the disease was isolated and appropriately named Legionella pneumophila.

What should you do if an employee or occupant at your facility is diagnosed with Legionnaires disease or Pontiac Fever? How would you respond? Who should be involved? Remember, a methodical approach is crucial. If there is a confirmed case of Legionnaires disease, or worse a death, it is critical to have a plan that addresses all the issues.

It is best to have a written, well though out plan in advance of any health related issue; however, with Legionnaires disease it is critical. The critical steps to reduce the potential for additional cases and to respond to the immediate issues includes:

• Shut off drinking water supplies, use bottled water
• Shutdown outdoor air intakes if there are cooling towers
• Consult with a physician to assess specific risk factors in other occupants such as: elderly, smokers and immunocompromised
• Consult with an industrial hygienist with significant expertise in Legionella assessments
• Industrial hygienists to conduct a walkthrough survey to identify potential Legionella bacteria reservoirs and pathways for potential exposure
• Develop sampling plan and collect water samples for Legionella analysis using Polymerase Chain Reaction  (PCR) and culturable methodologies
• Address human resource needs and facility related issues
• Evaluate hot water temperatures
• Evaluate current treatment and maintenance procedures for cooling towers and water distribution and storage systems
• Industrial hygienist to review laboratory data with medical and facilities components
• Design and implement treatment options based on laboratory results and water sources found to be positive with the Legionella bacteria
• Conduct follow-up sampling after treatment and any plumbing modifications
• Develop a Legionella Control Plan
• Conduct annual audits of the Plans effectiveness.

Here are a few facts worth remembering:

1. Legionella pneumophila accounts for 80% of Legionnaire disease cases
2. Up to 18,000 cases of Legionnaires’ disease are documented annually
3. Inhalation is primary route of exposure
4. Legionellosis is not passed from one person to another
5. The Legionella bacteria is naturally occurring and can be found in outdoor water sources
6. The Legionella bacteria grow best in warm water, typically 95 to 110oF
7. One colony of Legionella pneumophila in a drinking water system is a concern
8. There is no validated air sampling method for the Legionella bacteria
9. Treatment of water systems is not always effective due to slime layers, corrosion and sediment.

The analytical methods for quantifying / quantitating the concentration of Legionella bacteria in a sample of water include: direct florescent antibody (DFA), polymerase chain reaction (PCR) and culturable analysis. Culturable analysis will provide a quantitative concentration, the species and serotyping of the Legionella bacteria. Serotyping is critical to making a connection between a source and individual with the disease.

Remember, Legionella outbreaks can be prevented with the development and implementation of an effective Legionella Control Plan.

Need more information, or a proposal? Please click on Information Request, or contact Harry M. Neill, CIH at 888.873.9983, ext 15, or hneill@1ssh.com..

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Legionella and Legionnaires’ Disease

What should you do if an employee or occupant at your facility is diagnosed with Legionnaires’ disease or Pontiac fever? How would you respond? Who should be involved? A methodical approach to this situation is crucial. If there is a confirmed case of Legionnaires’ disease, or worse, a death, it is essential to have a plan that addresses all of the issues.

It is best to have a written, well-thought-out plan in advance of any health-related issue; however, with Legionnaires’ disease it is critical. Whenever there is a case of Legionnaires’ disease or Pontiac fever, the essential steps to reduce the potential for additional cases and to respond to the immediate issues include the following:

• Shut off drinking-water supplies; use bottled water
  
• Shutdown outdoor air intakes if there are cooling towers
  
• Consult with a physician to assess specific risk factors in other occupants such as the elderly, smokers and immuno-compromised individuals
  
• Consult with an industrial hygienist with significant expertise in Legionella assessments
• Have the industrial hygienist conduct a walk-through survey to identify potential Legionella bacteria reservoirs and pathways for potential exposure
• Develop a sampling plan and collect water samples for Legionella analysis using PCR and culturable methodologies
  
• Address human resource needs and facility-related issues
  
• Evaluate hot water temperatures
  
• Evaluate the current treatment and maintenance procedures for cooling towers and for water distribution and storage systems
  
• Have the industrial hygienist review laboratory data with medical and facilities components
  
• Design and implement treatment options based on laboratory results and water sources found to be positive for the Legionella bacteria
  
• Conduct follow-up sampling after treatment and following any plumbing modifications
  
• Develop a Legionella control plan
  
• Conduct annual audits of the plan’s effectiveness

Here are a few facts worth remembering:

• Legionella bacteria are naturally occurring and can be found in outdoor water sources
  
• Legionella bacteria grow best in warm water, typically 95 to 110 degrees Fahrenheit
  
• Just one colony of Legionella pneumophila bacteria in a drinking water system is a concern
  
• There is no validated air sampling method for the Legionella bacteria
  
• Treatment of water systems is not always effective due to slime layers, corrosion and sediment.

Remember, Legionella outbreaks can be prevented with the development and implementation of an effective Legionella control plan. For more information, please contact Harry M. Neill, CIH at 888-873-9983, ext. 15, or hneill@1ssh.com.

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Legionella Bacteria Prevention Planning

Legionella bacteria can be found in a variety of naturally occurring sources (e.g., soils, ponds and streams) in addition to man-made sources such as cooling towers, potable water systems, and heating, ventilation and air-conditioning (HVAC) systems. Legionella bacteria are present in public and well water supplies at extremely low concentrations. Legionella bacteria grow well in cooling towers and other indoor water systems, primarily because of the presence of warm water and available nutrients. If not properly treated, this warm water can promote the growth of algae, microbiological “slime” and amoebae, which enhance the potential for Legionella bacteria amplification.

Following the 1976 American Legion convention at the Bellevue Stratford Hotel in Philadelphia, 34 attendees died and 221 people became ill from pneumonia caused by the bacterium Legionella pneumophila. This disease, now commonly known as Legionnaires’ disease, is a respiratory infection that strikes susceptible individuals exposed to virulent Legionella bacteria. Infection results from inhaling airborne water droplets or mist containing viable disease-causing Legionella bacteria, which are small enough to pass deep into the lungs and be deposited in the alveoli, the small pockets in the lungs. The dose of Legionella pneumophila and other Legionella bacteria required to infect humans is not definitively known. Legionnaires’ disease can have an incubation period of two to ten days. Although healthy individuals can develop Legionnaires’ disease, people thought to be at increased risk of infection include smokers and patients with cancer, chronic respiratory disease, kidney disease or any immunosuppressed condition.

The purpose of a Legionella control program is to minimize the presence of Legionella bacteria and other environmentally associated bacteria in building waterside systems and consequently reduce the potential for illnesses associated with these organisms. The mechanism to achieve the above is to limit the ecological conditions (temperature range and nutrients) and physical plant (design) operations and maintenance issues that allow the Legionella bacteria to grow and amplify. However, note that complete elimination of Legionella bacteria in building water systems may not be possible. As such, instituting preventive maintenance procedures is a critical aspect of Legionella bacteria control. A well-designed control program includes the following information and procedures.

• Source Identification – Review design, operations and maintenance of waterside systems (e.g., hot water tanks, cooling towers, HVAC systems, humidifiers,  piping networks, process water and distribution systems) for source identification and to perform a risk assessment to determine the likelihood that the system harbors Legionella bacteria and the potential for exposure to aerosolized water droplets or mist.
  
  
• Preventive Maintenance - Develop site-specific guidelines for preventive maintenance procedures for each of the waterside systems for cleaning and maintenance of environmental conditions, such as temperature ranges and water treatments, to reduce the potential for amplification of Legionella bacteria.
  
  
• Sampling and Analytical Procedures, and Data Interpretation - Determine the best practices for water sampling, including location, frequency of sampling and data interpretation, in relation to preventive maintenance and risk assessment.
  
  
• Decontamination Guidelines - Develop site-specific guidelines for decontamination of each waterside system, including mechanical cleaning, chemical treatment options and heat pasteurization techniques.
  
  
• Emergency Response Procedures - Identify the appropriate team members from within the facility and outside resources, including facilities/physical plant personnel, safety team, medical workers, experienced industrial hygiene consultant, environmental laboratory technician, chemical treatment vendor and field sample collection team, to efficiently respond to high concentrations of Legionella bacteria in samples or a Legionnaires’ disease outbreak.

For additional information or to request a proposal, please contact Harry M. Neill, CIH, at 888-873-9983, ext. 15, or hneill@1ssh.com.

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