Same observations were noted after 12 h incubation. After 15 h
incubation, flukes in the control group remained motile while
flukes exposed to different concentrations of lead showed signs
of immobility. Therefore, immobile flukes were stained with 1%
methylene blue to determine the motility score of each fluke. No
significant visual differences observed between flukes with a
motility score of 1 and 0.