Schistosoma

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PARASITES
TREMATODES



Schistosoma Species

  • The schistosomes are also known as "blood-flukes".
  • There are several important species producing serious human and animal disease in the tropics.
  • The pathology is mostly associated with the passage of eggs through the liver, urinary bladder or intestinal wall (depending on the predilection site of the fluke).
  • As their common name suggests, the adults live in blood-vessels.
  • Unusually for a trematode, the sexes are separate.
  • The smaller female lies enveloped by the male.
  • The eggs of most species have spikes to assist their passage through host tissue to get into faeces or urine (depending on predilection site).
  • The intermediate hosts are water snails.
  • On release, the cercariae swim in water and actively seek their final host, which they enter by skin penetration - there is, therefore, no metacercaria stage.