S. mansoni cercaria emerging from their intermediate snail host Biomphalari glabrata

In a continuing collaboration with Dr. Fred Lewis at The Biomedical Research Institute (BRI), Rockville, MD we have recently used the Hitachi SEM to obtain images of S. mansoni cercaria emerging from the tegument of their intermediate snail host Biomphalari glabrata. Once the parasite matures in the snail host it forces its way out into the water column where it can contact a suitable mammalian host to continue the life cycle. Dr. Lewis and his colleagues have used light microscopy to observe a cercaria emerging and have taken histological sections to see groups of cercariae before shedding. Their and others’ observations indicate that shedding occurs tail-first, head-first, and by bursting of groups from a bleb.

Our SEM images are of tail-first emergence and of groups encased in a thin tissue matrix with the rare emergence of a cercaria head-first. Use of the SEM allows for a close up of these processes. The accompanying image is of the tail-first emergence of a cercaria through the tegument of a B. glabrata snail. In collaboration with Dr. Granath and Dr. Driver images taken on the University of Montana’s SEM and on our Olympus phase-contrast microscope have been combined with other data and presented by Dr. Fred Lewis and Dr. Matt Tucker at the 2012 American Society of Parasitologists 87th Annual Meeting in Richmond, VA.

S. mansoni cercaria emerging from their intermediate snail host Biomphalari glabrata

S. mansoni cercaria emerging from the tegument of their intermediate snail host Biomphalari glabrata.