SCHISTOSOMA-MANSONI - CERCARIAL SHEDDING PATTERNS FROM A MIXED INFECTION OF BIOMPHALARIA-GLABRATA WITH 2 (EARLY AND LATE) CHRONOBIOLOGICAL VARIANTS

The cercarial emergence rhythms of Schistosoma mansoni were analyzed f or mixed infection of the snail Biomphalaria glabrata with two chronob iological strains, one with an early shedding pattern and the other wi th a late shedding pattern. Under these conditions, each parasite stra in kept its own circadian cercarial emergence pattern. When the chrono biological variants were of the same species, no interference between the trematode larvae occurred during the cercarial emergence process. These results confirm that within the host-parasite system the parasit e component is directly responsible for the cercarial emergence patter n.