Helminthes

Helminthes
Trematodes

General characteristics
- Fluke is the common name for any member of the class Trematoda - Trematodes are relatively simple, flatworms, soft-bodied, the fluke body is unsegmented and covered by a tough cuticular tegument for its protection from digestive enzymes of the host. - Possess two suckers, one oral anterior in position and surrounding the mouth and the other the ventral lying on the ventral surface. - They have a blind digestive system, i.e. without anus: the only opening is the mouth. waste products are regurgitated. - Most are hermaphroditic and capable of self-fertilization. except for schistosoma, which have separate male and female. - Have complicated life cycle occurring in two or more host, involving sexual reproduction in mammalian and other vertebrate (definitive hosts) and asexual reproduction in snail (intermediate hosts). Each species requires a certain species of snail as an intermediate host. - Trematode eggs usually have a smooth, hard, transparent, yellow-brown shell and may have spines - Reproductive system: Uterus is the largest organ; a single ovary, testes and a series of glandular structures that produce egg. Uterus may be filled with thousands of eggs. - Trematodes infect various organs of the human host (for example, intestinal veins, urinary bladder, liver, or lung).
Types of Flukes
Blood flukes: Schistosoma
Life cycle
Pathogenicity
Clinical finding
Diagnosis

Diagnosis is based on a history of residence in an endemic area, swimmers itch and other symptoms. Stool or urine (S. haematobium occasionally S. japonicum) is examined for eggs. The eggs are very characteristic and confirm diagnosis. Eggs are distinguished by spines and its different according to the species:

- Schistosoma mansoni has large lateral spine
- Schistosoma japonicum has small lateral spine
- Schistosoma haematobium has terminal spine
Treatment