Longevity of Trichobilharzia stagnicolae miracidia in various aqueous solutions and during desiccation

Abstract

Swimmer’s itch is caused by nonhuman schistosomes, including Trichobilharzia stagnicolae, which have complex indirect life cycles. Miracidia are a free living life cycle stage of these schistosomes that are transmitted from either an avian or mammalian host to a specific snail intermediate, depending on the species. The goals of this study are to determine the life span of the miracidia of T. stagnicolae in various solutions and to examine the effect of desiccation on the hatching ability of miracidia. Miracidia were hatched and placed in dishes of five different solutions (filtered lake water, well water, distilled water, distilled water with sucrose and avian ringers) to determine their life span. Samples of host fecal material were dried and miracidia were hatched from these samples to test the effects of desiccation. Longevity of miracidia was greatest in filtered lake water and distilled water. Hatching ability decreased with the amount of water evaporated from the fecal samples (p = 4.03x10-10). These results suggest that T. stagnicolae miracidia are sensitive to hyperosmotic solutions and that once they hatch, they lose many protective functions provided by the egg.