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Ultrastructure of the Tegument of Schistosoma

1973; Elsevier BV; Linguagem: Inglês

10.1016/s0065-308x(08)60188-8

2163-6079

D. J. Hockley,

Helminth infection and control

This chapter discusses ultrastructure of the tegument of Schistosoma mansoni at all stages of the life cycle. The chapter has four main sections dealing respectively with the cercaria, the schistosomulum, the adult trematode, and miracidium and sporocyst. The cercaria section concerns the development of the tegument, the cercarial surface coat, and associated structures of the tegument in developed cercariae. A syncytial tegument connected to subtegmental cells occurs in all adult digenetic trematodes that have been examined and this unusual structure involves unusual cytoplasmic inclusions that are also related to the host-parasite interface. Specialized regions of tegument occur in the oesophagus and the uterus that are regarded as tegumental structures but differ in structure. The oesophagus is primarily concerned with digestion and the function of the intestinal caecum is absorption and egestion. Destruction of the tegument is specially considered in respect of the effects of hypo- and hypertonic media and drugs and host immunity. Finally, the epithelium and associated structures of the miracidium are considered and the contrasting tegument of the daughter sporocyst, which has the syncytial tegument and nucleated subtegumental cells of the typical digenetic trematode. All these and other matters are considered in such intricate detail as is necessary at this time, when ultrastructural detail can improve the understanding of the host-parasite relationship in established schistosomiasis.