1. Class Trematoda

2. General characters
Flat worms (no cavity),not segmented, bilaterally flattened (except Schistosoma is cylindrical)
Hermaphrodite (except Schistosoma)
Body has 2 suckers for attachment :oral, ventral,(except Heterophyes has a 3 rd genital sucker

3. General characters
Life cycle show sexual phase (defenitive host) and asexual phase (intermediate host)
Require one or more intermediate host
1st intermediate host is a snail
Eggs have an operculum
Infective stage is encysted
metacercaria
(except schistosoma: cercariae)

4. Heterophyes heterophyes
Heterophyes heterophyes adult
Heterophyes heterophyes eggs: Heterophyes heterophyes snail
Heterophyes heterophyes encysted metacercaria
Heterophyes heterophyes in small intestine

5. snail: Pirenella conica
Eggs: small, operculated, yellowish brown, thin shell (H.P)

6. pear shaped,
very small size, (2mm)
oral,ventral, genital suckers
vitelline glands
2 testis, 1 ovary
simple intestinal ceaca
(L.P)

7. Heterophyes heterophyes adult in small intestine
Adult worm is present in intestinal villi

8. Heterophyes heterophyes encysted metacercaria in Bouri and Bolti muscles

9. Heterophyes heterophyes
Location of adult: small intestine
Intermediate host:
Primary: Pirenella conica
Secondary: Bolti and Bouri fish
Infective stage: encysted metacercaria
Mode of transmission: ingestion of raw fish containing encysted metacercaria
Diagnosis: eggs in stool
Disease: heterophiasis

10. Fasciola Fasciola hepatica adult Fasciola gigantica adult
Fasciola gigantica snail: (lymnaea cailliaudi )
Fasciola egg

11. OS: oral sucker
VS: ventral sucker
OV: ovary
TE: testis
Vi: vitelline glands
UT: uterus
INC: intestinal caeca
GP: genital pore

12. Fasciola hepatica Fasciola gigantica
Less prominent shoulders, parallel margins, medial branches are T or Y shaped, larger in size
cephalic cone, 2 shoulders, converging margins, simple medial branches of intestinal caeca,smaller in size

13. Snail (Lymnae caillaudi)
Fasciola egg:very large, operculated, yellow, thin shell

14. Location of adult: bile duct
Intermediate host :
primary : snail Lymnaea truncatula for F.hepatica and Lymnaea. cailliaudi for
F. gigantica
secondary: leaves of fresh-water plants
Mode of transmission: ingestion of raw water-cress containing encysted metacercariae
Infective stage: encysted metacercaria
Diagnosis: eggs in stool
Disease: Fascioliasis

15. Schistosoma sp. Schistosoma mansoni male Schistosoma mansoni female
Schistosoma mansoni male&female
Eggs of Schistosoma mansoni
Eggs of Schistosoma haematobium
Snail of Schistosoma mansoni
Snail of Schistosoma haematobium
S.mansoni cercaria

16. S. mansoni
S. mansoni male:8-10 mm, has gynacophoric canal, dorsal surface covered with tubercle
S. mansoni female:14 mm, taller and thinner,vitelline glands occupy 2/3 of the body
S.mansoni male&female

17. S. mansoni snail Biomphlaria alexandrina
S. mansoni egg:oval with lateral spine
Cercaria of S.mansoni: elongated head, biforked tail
S. mansoni snail Biomphlaria alexandrina

18. S. Hematobium
Egg: oval with terminal spine
Snail:Bulinus truncatus

19. S.mansoni S.hematobium
Location:veins of large intestine, colon (lower mesentric vein
Intermediate host:Biomphalaria alexandrina
Diagnosis: eggs in stool
Infective stage: cercariae
Mode of transmission:direct skin penetration of cercariae during swimming
Disease: Intestinal Bilharziasis
veins of urinary bladder (venous plexus of urinary bladder)
Bulinus truncatus
Eggs in urine
Cercariae
direct skin penetration of cercariae during swimming
Urinary Bilharziasis