SCHISTOSOMA-MANSONI MIRACIDIAL HOST-FINDING - SPECIES-SPECIFICITY OF AN EGYPTIAN STRAIN

The effect of snail-conditioned water (SCW) from Biomphalaria alexandr ina, a pigmented and an albino strain of B. glabrata, and Lymnaea stag nalis on the host-finding behavior of miracidia of two Brazilian and o ne Egyptian strain of Schistosoma mansoni was studied. Miracidia of th e Egyptian strain significantly preferred their suitable host B. alexa ndrina versus the other snail species with their behavior patterns of host location and their responses after contact with the host. However , miracidia of both Brazilian strains did not differentiate between SC W from three of the snail species; only the pigmented B. glabrata elic ited weaker responses. The releasing cues of SCW for miracidial host-f inding phases are macromolecular glycoconjugates. An analysis of SCW b y sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) , blotting, and subsequent carbohydrate detection showed that the band patterns of glycoconjugates differed significantly among the four sna il strains. Therefore, differing chemical characteristics of the signa ling glycoconjugates could be the basis for the observed host specific ity in miracidial host-finding.