Dynamics of the leukocytic response of Biomphalaria glabrata during the larval development of Schistosoma mansoni and Echinostoma liei

The daily evolution of the number of hemocytes in Biomphalaria glabrata was ascertained under three conditions: uninfected snails, snails infected with Schistosoma mansoni, and snails infected with Echinostoma liei. The Results show differences between the three experiments as well as in the average hemocyte density over the whole experimental period, as in the temporal dynamics of circulating hemocyte number. Specifically, it appears that the development of E. liei in B. glabrata induces a density of circulating hemocytes greater than that in uninfected B. glabrata or in snails infected with S. mansoni. The hemocyte dynamics observed in both experimental groups might best be interpreted by taking into account differences in the immunogenic stimulating capacity of the two trematodes and different physiological functions of the hemocytes brought into play during the infection: wound repair, nutrient digestion and transport, and excretion.