This document describes the life cycles of several trematode parasites, including Fasciola hepatica, Fasciolopsis buski, Clonorchis sinensis, Heterophyes heterophyes, Paragonimus westermani, and Schistosoma species. It outlines the adult worm stage in the definitive host, egg production, miracidium hatching from eggs in water, infection of an intermediate snail host where asexual reproduction occurs, release of cercaria from snails which may infect other hosts or humans, and the metacercaria cyst stage for some species. Diagrams show the adult worm morphology and egg characteristics to identify each parasite species.

2. Adult worm in human & other
vertiberates (sexual reproduction)
Eggs in fresh water (3-7
weeks)
Miracidium (swimming
free in water )
Sporocyst (soft tissue of the
aproprate intermediat
host"snail“ (asexual
reproduction)
1st & 2nd generation of
Redia (snail)
Cercaria free in fresh
water
Metacercaria
(other trematodes)
Schistosoma

3. Fasciola hepatica

5.  large and broadly-
flattened,
 measuring up to
30 mm long and 15
mm wide.
The anterior end is
cone-shaped.
Extensive branching
of: intestinal ceca,
testes and vitelline
follicles.
Fasciola hepatica
A. Adult:

7. Fasciola hepatica A: Adult
Fasciola hepatica Adult 20 – 30 mm L. X 8
– 13 mm B, ( grey – brown )
Carmine s.

8. Fasciola hepatica
B-Ovum
Large ,
Single celled
Unembryonated
with operculum

10. Fasciola hepatica
C-Miracidium
Ciliated,
Swimming in water
Many celled.

11. Fasciola hepatica
D-Redia
Sac - like structure with germ cells,
Clusters of germ cells differentiate
into daughter redia or cercaria

12. Fasciola
hepatica
E. Cercaria:
Anterior trunk
Posterior tail,
Leaving snail to
swim in water.

13. Fasciola hepatica
F. Metacercaria:
Globose structures
Encysted on aquatic vegetation.

14. Rediae
sporocysts
Miracidium
Cercaria
Metacercaria
stages from Fasciola hepatica life cycle
Egg

15. Lab. 7:
Fasciolopsis buski
Clonorchis sinensis
Heterophyes heterophyes
paragonimus westermani

16. Fasciolopsis buski

18. Fasciolopsis buski
A. Adult
similar, but larger than F.
hepatica.

19. Intestinal fluke
Fasciolopsis buski
(Fasciolopsiasis).
•Large fleshy worm Size 20-75
mm X 8-20 mm.
•Oral sucker is smaller than the
ventral sucker.
•Testes are highly branched in
the posterior 3/5 of the body.
•Small branched ovary.
•Short convoluted uterus.

20. Fasciolopsis buski
Oral sucker
Intestinal ceca

21. Adult fluke of Fasciolopsis buski The adult flukes
range in size: 20 to 75 mm by 8 to 20 mm

22. Clonorchis sinensis

24. Clonorchis sinensis
A. Adult:
Long, lanceolate body
 Digestive tract:
• simple,
• esophagus short,
• 2 unbranched intestinal
ceca
 Testes 2, branched.
 Vitelline gland, many in
lateral position.
 Uterus coiled.
 Ovary single.

25. Oral sucker
Ventral sucker
Uterus
Ovary
2 branched testes
Intestinal ceca
Vitelline
gland

27. Adults of Clonorchis sinensis

28. Clonorchis sinensis
B. Egg
Distinct operculum.
Small knob at the
opposite end.
Contains a fully
developed miracidium
when discharged in the
faeces.

29. Clonorchis sinensis : Eggs
Iodine s.
Saline s.

30. Heterophyes heterophyes

32. Heterophyes heterophyes
A. Adult
 Size very small.
 Intestinal ceca unbranched.
 Suckers 3,oral,ventral
and genital.
 Genital sucker adjacent to
ventral sucker.
 Testes 2 rounded
unbranched.
2 rounded testes

33. 2 rounded testes
Genital sucker
Acetabulum
Intestinal ceca
Oral sucker
Ovary

34. Pulmonary fluke
paragonimus westermani
(Paragonimiasis)

36. paragonimus westermani
A. Adult:
 Shape rounded 7.5-12mm
long X 4-6mm wide &
3.5-5mm deep.
 wave ceca.
 Oral sucker & acetabulum
almost equal in size.
 Testes slightly branched
parallel to each other.
 Ovary single, anterior to
testes.

37. 2 testes
Uterus
Ovary

41. Schistosoma spp.
A. Adult in copula
 Separate sexes
 Long thin female
 Short broad male,
 With gynecophoric
canal enclosing
female

43. Schistosoma ssp male and female in copula

44. 7. Schistosoma spp.
a. adult male & female
Ventral sucker
Oral sucker

45. 7. S. haematobium
Ovum with spine
terminal

46. S. mansoni
ovum with lateral spine

48. S. japonicum
spine knob- like, lateral

49. Schistosoma japonicum Egg
Saline s.

50. Schistosoma haematobium
Egg ( in urine )
Schistosoma mansoni
Egg in stool )
Schistosoma japonicum Egg
Ova of Schistosoma spp.

51. Schistosoma spp.
C. Cercaria-forked-tailed.