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

Trematodes

Pathology and ParasitologyCourse Code: 401

Parasitology-lab # 2

1

Department of Microbiology & ImmunologyFaculty of Pharmacy

Cairo University

Helminthology

Helminths• Helminths (worms) are multicellular parasites.• • They are divided into:

1- Round Worms 2- Flat Worms

(Nemathelminths) (Platyhelminths)

Class Nematoda (Flukes) (Tape worms)

Class Trematoda Class Cestoda 2

Helminthology

Questions form:• Name of the parasite• Intermediate host• Infective stage• Mode of transmission• Location in the host• Lab diagnosis (Diagnostic stage)• Disease3

Class TrematodaClass Trematoda(Flukes)(Flukes)

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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)

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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)

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• General life cycle of trematodes1. 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). 7

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1- Intestinal Fluke1- Intestinal Fluke Heterophyes heterophyes

• Heterophyes heterophyes adult

• Heterophyes heterophyes eggs

• Heterophyes heterophyes snail

• Heterophyes heterophyes encysted metacercaria

• Heterophyes heterophyes in small intestine

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• pear shaped

• very small size (2mm)

• oral, ventral, & genital suckers

• vitelline glands

• 2 testis, 1 ovary

• simple intestinal ceaca Heterophyes heterophyes adult

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Heterophyes heterophyes adult in small intestine

Adult worm is present in intestinal villi

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: heterophiasis11


Intermediate host:

first: Pirenella conica

Second: Bolti and Bouri fish




Disease: heterophiasisSnail: Pirenella conica

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Heterophyes heterophyes encysted metacercaria in Bouri

and Bolti muscles






Disease: heterophiasis

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Eggs: small, operculated, yellowish brown, thin shell (H.P)






Disease: heterophiasis

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• 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

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2- Liver Fluke2- Liver Fluke Fasciola

• Fasciola hepatica adult

• Fasciola gigantica adult

• Fasciola gigantica snail: (lymnaea cailliaudi )

• Fasciola egg

• Fasciola metacercaria

• Fasciola redia16

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Fasciola hepatica Fasciola gigantica

2 prominent shoulders, converging margins, simple medial branches of intestinal

caeca, smaller in size

Less prominent shoulders,

parallel margins, medial branches

are T or Y shaped, larger

in size18

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


Diagnosis: eggs in stoolDisease: Fascioliasis

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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. giganticasecond: leaves of fresh-water plants

Mode of transmission: ingestion of raw water-cress containing encysted metacercariae



Disease: Fascioliasis

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• 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: Fascioliasis21

33 - -Blood FlukeBlood 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 22

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

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S. haematobium

S. haematobium male S. haematobium female

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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


Disease: Intestinal Bilharziasis

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S. mansoni snail Biomphlaria alexandrina







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Cercaria of S. mansoni: elongated head, biforked

tail







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S. Hematobium

Egg: oval with terminal spine

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

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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

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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

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Slides of trematodes

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Heterophyes heterophyes adult

Eggs: small, operculated, yellowish brown, thin shell

(H.P)

Heterophyes heterophyes

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Snail: Pirenella conica

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Heterophyes heterophyes adult in small intestine

Adult worm is present in intestinal villi

Heterophyes heterophyes encysted metacercaria in Bouri

and Bolti muscles

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Fasciola hepatica Fasciola gigantica

2 prominent shoulders, converging margins, simple medial branches of intestinal

caeca, smaller in size

Less prominent shoulders,

parallel margins, medial branches

are T or Y shaped, larger

in size35

Snail Lymnaea cailliaudi

Fasciola egg: very large, operculated, yellow, thin shell

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Cercaria of S. mansoni: elongated head, biforked tail

S. mansoni snail Biomphlaria alexandrina

S. mansoni egg: oval with lateral spine

S. mansoni

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Egg: oval with terminal spine

Snail: Bulinus truncatus

S. haematobium

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Documents

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