Schistosoma mansoni, Echinostoma lindoense, and Paryphostomum segregatum: Interference by trematode larvae with acquired resistance in snails, Biomphalaria glabrata

Abstract

Many juvenile albino Biomphalaria glabrata snails with an acquired resistance to Echinostoma lindoense again became susceptible to this trematode parasite following infection with either of two other larval trematodes, Paryphostomum segregatum or Schistosoma mansoni. Previous studies have shown that trematode sporocysts are capable of interfering with juvenile and adult natural resistance to S. mansoni. We propose that a common mechanism is present that allows both juvenile and adult natural resistance and acquired resistance to trematodes in B. glabrata to be reduced strikingly by the simultaneous presence of trematode larvae in the snail host.