1. Trematodes Pathology and Parasitology Course Code: 401
Parasitology-lab # 2
Trematodes
Department of Microbiology & Immunology
Faculty of Pharmacy
Cairo University

2. Helminthology Helminths Helminths (worms) are multicellular parasites.
They are divided into:
1- Round Worms Flat Worms
(Nemathelminths) (Platyhelminths)
Class Nematoda (Flukes) (Tape worms)
Class Trematoda Class Cestoda

3. Helminthology Questions form: Name of the parasite Intermediate host
Infective stage
Mode of transmission
Location in the host
Lab diagnosis (Diagnostic stage)
Disease

4. Class Trematoda (Flukes)

5. General Characters
1- Flat worms (no body cavity), not segmented, bilaterally flattened (except Schistosoma is cylindrical)
2- No respiratory nor vascular system.
3- Hermaphrodite (except Schistosoma)

6. 4- Body has 2 suckers for attachment: oral, ventral, (except Heterophyes has a 3 rd genital sucker)
5- Life cycle show sexual phase (definitive host) and asexual phase (intermediate host)
6- Require one or more intermediate host
7- 1st intermediate host is a snail
8- Eggs have an operculum (except Schistosoma)
9- Infective stage is encysted metacercaria
(except Schistosoma: cercariae)

7. General life cycle of trematodes
1. Eggs are released from human (in feces or urine) in fresh water.
2. Eggs hatch into first larval stage (miracidial larva) that invade a snail as first intermediate host.
3. All trematodes except Schistosoma sp. require a second intermediate host which is mostly a water plant or animal.
4. The second larval stage (cercarial or metacercarial larva) comes out of the intermediate host(s).
5. Humans are infected through direct penetration of cercaria (Schistosoma) or ingestion of encysted metacercaria in water plant or animal (all other trematodes).

9. 1- Intestinal Fluke Heterophyes heterophyes
Heterophyes heterophyes adult
Heterophyes heterophyes eggs
Heterophyes heterophyes snail
Heterophyes heterophyes encysted metacercaria
Heterophyes heterophyes in small intestine

10. oral, ventral, & genital suckers
pear shaped
very small size (2mm)
oral, ventral, & genital suckers
vitelline glands
2 testis, 1 ovary
simple intestinal ceaca
Heterophyes heterophyes adult

11. Heterophyes heterophyes adult in small intestine
Location of adult: small intestine
Intermediate host:
first: Pirenella conica
Second: Bolti and Bouri fish
Infective stage: encysted metacercaria
Mode of transmission: ingestion of raw or udercooked fish containing encysted metacercaria
Diagnosis: eggs in stool
Disease: heterophiasis
Heterophyes heterophyes adult in small intestine
Adult worm is present in intestinal villi

12. Snail: Pirenella conica
Location of adult: small intestine
Intermediate host:
first: Pirenella conica
Second: Bolti and Bouri fish
Infective stage: encysted metacercaria
Mode of transmission: ingestion of raw or udercooked fish containing encysted metacercaria
Diagnosis: eggs in stool
Disease: heterophiasis
Snail: Pirenella conica

13. Location of adult: small intestine
Intermediate host:
first: Pirenella conica
Second: Bolti and Bouri fish
Infective stage: encysted metacercaria
Mode of transmission: ingestion of raw or udercooked fish containing encysted metacercaria
Diagnosis: eggs in stool
Disease: heterophiasis
Heterophyes heterophyes encysted metacercaria in Bouri and Bolti muscles

14. Eggs: small, operculated, yellowish brown, thin shell (H.P)
Location of adult: small intestine
Intermediate host:
first: Pirenella conica
Second: Bolti and Bouri fish
Infective stage: encysted metacercaria
Mode of transmission: ingestion of raw or udercooked fish containing encysted metacercaria
Diagnosis: eggs in stool
Disease: heterophiasis
Eggs: small, operculated, yellowish brown, thin shell (H.P)

15. Location of adult: small intestine
Intermediate host:
First : Pirenella conica
Second: Bolti and Bouri fish
Infective stage: encysted metacercaria
Mode of transmission: ingestion of raw or udercooked fish containing encysted metacercaria
Diagnosis: eggs in stool
Disease: heterophiasis

16. 2- Liver Fluke Fasciola Fasciola hepatica adult
Fasciola gigantica adult
Fasciola gigantica snail: (lymnaea cailliaudi )
Fasciola egg
Fasciola metacercaria
Fasciola redia

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

19. Snail (Lymnaea cailliaudi )
Location of adult: bile duct
Intermediate host :
first: snail Lymnaea truncatula for F. hepatica and Lymnaea cailliaudi for F. gigantica
second: 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
Snail (Lymnaea cailliaudi )

20. Fasciola egg: very large, operculated, yellow, thin shell
Location of adult: bile duct
Intermediate host :
first: snail Lymnaea truncatula for F. hepatica and Lymnaea cailliaudi for
F. gigantica
second: 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
Fasciola egg: very large, operculated, yellow, thin shell

21. first: snail Lymnaea truncatula for
Location of adult: bile duct
Intermediate host :
first: snail Lymnaea truncatula for
F. hepatica and Lymnaea cailliaudi for
F. gigantica
second: 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

22. 3- Blood Fluke Schistosoma spp.
Schistosoma mansoni male
Schistosoma mansoni female
Schistosoma mansoni male & female
Schistosoma haematobium male
Schistosoma haematobium female
Eggs of Schistosoma mansoni
Eggs of Schistosoma haematobium
Snail of Schistosoma mansoni
Snail of Schistosoma haematobium
S. mansoni cercaria

23. S. mansoni
S. mansoni male: 8-10 mm, has gynaecophoric 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

24. S. haematobium
S. haematobium male
S. haematobium female

25. S. mansoni egg: oval with lateral spine
Location: veins of large intestine, colon (lower mesentric vein)
Intermediate host: Biomphalaria alexandrina
Infective stage: cercariae
Mode of transmission: direct skin penetration of cercariae during swimming
Diagnosis: eggs in stool
Disease: Intestinal Bilharziasis
S. mansoni egg: oval with lateral spine

26. S. mansoni snail Biomphlaria alexandrina
Location: veins of large intestine, colon (lower mesentric vein)
Intermediate host: Biomphalaria alexandrina
Infective stage: cercariae
Mode of transmission: direct skin penetration of cercariae during swimming
Diagnosis: eggs in stool
Disease: Intestinal Bilharziasis
S. mansoni snail Biomphlaria alexandrina

27. Cercaria of S. mansoni: elongated head, biforked tail
Location: veins of large intestine, colon (lower mesentric vein)
Intermediate host: Biomphalaria alexandrina
Infective stage: cercariae
Mode of transmission: direct skin penetration of cercariae during swimming
Diagnosis: eggs in stool
Disease: Intestinal Bilharziasis
Cercaria of S. mansoni: elongated head, biforked tail

28. Egg: oval with terminal spine
S. Hematobium
Location: veins of urinary bladder (venous plexus of urinary bladder)
Intermediate host : Bulinus truncatus
Diagnosis: Eggs in urine
Infective stage : Cercariae
Mode of transmission :direct skin penetration of cercariae during swimming
Disease :Urinary Bilharziasis
Egg: oval with terminal spine

29. Snail: Bulinus truncatus
Location: veins of urinary bladder (venous plexus of urinary bladder)
Intermediate host : Bulinus truncatus
Diagnosis: Eggs in urine
Infective stage : Cercariae
Mode of transmission :direct skin penetration of cercariae during swimming
Disease :Urinary Bilharziasis
Snail: Bulinus truncatus

30. S. mansoni S. haematobium
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

31. Slides of trematodes

32. Heterophyes heterophyes
Eggs: small, operculated, yellowish brown, thin shell (H.P)
Heterophyes heterophyes adult

33. Snail: Pirenella conica

34. Heterophyes heterophyes adult in small intestine
Heterophyes heterophyes encysted metacercaria in Bouri and Bolti muscles
Heterophyes heterophyes adult in small intestine
Adult worm is present in intestinal villi

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

36. Snail Lymnaea cailliaudi
Fasciola egg: very large, operculated, yellow, thin shell

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

38. S. haematobium
Snail: Bulinus truncatus
Egg: oval with terminal spine