| Abstrakt: |
Cooling towers are associated with transmission of the bacterium Legionella, the agent of Legionnaires' Disease and Pontiac Fever. This study analyzed the numbers of Legionella pneumophilacollected from 1,336 commercial and industrial cooling towers over a 4-year period. These cooling towers were routinely treated with biocides to reduce the growth of Legionella. Comparisons of Legionellanumbers showed that 46% of the cooling towers contained no detectable L. pneumophila, 59% had counts of 10/ml or less, 90% had counts at or below 200/ml, and only 3% contained over 1,000/ml. Cooling tower samples containing Legionellaoccurred every month of the year with higher numbers during the summer months when more cooling towers were operating. |
