FIG. 4.

Effect of changing flow media on oocyst retention by biofilm. The cumulative percentage of oocysts associated with the biofilm over time with fall biofilm grown with fall water, fall biofilm grown with spring water, spring biofilm grown with fall water, and spring biofilm grown with spring water was determined. The error bars show the percent standard error (n = 2) and are smaller than the symbols where not visible. The black line on the time axis indicates the period of oocyst dosing (0 to 72 h).