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