Comparing the viability quantified with fluorescence assays and microscopy.

Samples containing 100 ± 4 cercariae with a viability of 30% ± 2% were stained with FDA-PI and FDA-H. Measurements were taken at 20 minutes. Three 50 μl aliquots of each sample were then examined under the microscope, and cercarial viability was recorded by counting moving (viable) and non-moving (non-viable) cercariae. Average quantified viabilities and SEMs are shown on the bar graph. The “actual” viability is the known proportion of live and dead cercariae in each well, chosen as 30%.