FIG. 1.
Concentrations of Legionella spp. (▪) and L. pneumophila (▵) in a cooling tower facility as determined by quantitative PCR. When detection of L. pneumophila occurred but at concentrations below the quantification threshold, results are represented by double arrows. When the concentration was below the detection threshold, results are represented by single arrows. The detection thresholds of Legionella spp. and L. pneumophila are indicated, respectively, by solid and dotted lines (Legionella detection threshold = 3.3 log GU liter−1, L. pneumophila detection threshold = 2.8 log GU liter−1). Stars indicate combined biodispersant and biocide treatments.