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Epidemic Legionnaires' disease. Airborne transmission down a chimney

J D Band, M LaVenture, J P Davis

    JAMA
    |June 19, 1981
    PubMed

    Insights

    Legionnaires' disease outbreaks can be linked to contaminated cooling towers. This study identified a hotel's cooling tower as the source of an outbreak, with contaminated air entering a meeting room via a chimney.

    Area of Science:

    • Environmental Health
    • Infectious Disease Epidemiology
    • Microbiology

    Background:

    • Legionnaires' disease (LD) is a severe pneumonia caused by Legionella bacteria.
    • Identifying the source of LD outbreaks is crucial for public health interventions.

    Observation:

    • An outbreak of 13 LD cases occurred among visitors to a Wisconsin hotel complex in 1979.
    • All affected individuals had visited building A, which housed restaurants and meeting rooms.
    • Legionella pneumophila was isolated from the hotel's cooling tower water.

    Findings:

    • Exposure to meeting room 1 was associated with a higher risk (1.5%) of developing LD.
    • Cooling tower exhaust was traced into meeting room 1 through an adjacent chimney.
    • Continuous hyperchlorination of cooling tower water and sealing the chimney halted new cases, with a seven-day lag.

    Implications:

    • Cooling towers can be reservoirs for Legionella, posing a risk of airborne transmission.
    • Architectural features, like chimneys, can facilitate the spread of contaminated aerosols into indoor environments.
    • Effective disinfection and environmental control measures are essential to prevent Legionnaires' disease outbreaks.

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