Each exposure group was composed of a total of 150 snails from 5 months of collection (n=30 snails/exposure/month).
Number of light exposures represents the number of times a given batch of snails received a 6-hour light exposure with an average ~1000 lux light intensity. There were no significant differences among the numbers of infected snails in the different treatment groups (p>0.05)
Values with the same letter are not significantly different from each other (p>0.05). Values with different letters are significantly different from each other (p<0.001).