ParasitologyParasitology

Parasitology

ProtozologyHelmintholo

gyEntomolog

y

Classification:

Helminthology

Platyhelminthes(Flat worms)

Nematohelminthes (Round worms)

Trematoda (Flukes) Ceastoda

(Tape worms)

Nematoda

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Trematodes of medical Trematodes of medical importance in our courseimportance in our course

Heterophyes heterophyes

Fasciola hepatica & Fasciola gigantica

Schistosoma haematobium & Schistosoma mansoni

Schistosoma Schistosoma

haematobium haematobium

& &

Schistosoma mansoniSchistosoma mansoni

Name:Name: Schistosoma haematobium

Schistosoma mansoni

Definition:-Definition:- Blood Flukes (Bilharzia)

Distribution:Distribution: Egypt, Africa & middle east

Africa, Latin America & portirico.

Disease:Disease: Urinary Schistosomiasi

s

Intestinal Schistosomiasi

s

Unlike trematodesUnlike trematodes• Schistosoma has only one intermediate host.• No reservoir.• Schistosoma eggs not operculated.• Forked tail cercaria.• Cylindrical worm.• It is the only trematode in which sex is

separated while other trematodes are hermaphrodite.

Habitat:Habitat:

Definitive host:Definitive host:

Intermediate host:Intermediate host:

Reservoir:Reservoir:

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Diagnostic Diagnostic Stage:Stage:

Infective Stage:Infective Stage:

Mode of Mode of infection:infection:

Treatment:Treatment:

Prevention: Prevention:

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SchistosomiasisSchistosomiasis Most cases are a symptomatic. Symptoms:-• Urinary Schistosomiasis haematouria (blood in urine).• Intestinal Schistosomiasis gastrointestinal bleeding. General complications of chronic

Schistosomiasis are due to the presence of Schistosoma eggs in tissues of spleen, gut wall or urinary bladder walls.

Egg inflammation granuloma fibrosis, hepatomegaly & portal

hypertension

Portal hypertension speelnomegaly ascitis & oesophageal varicose. S. haematobium eggs in bladder walls fibrosis, increase the frequency of bacterial

infections bladder carcinoma or sterility.

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No damage in hepatocytes

S. mansoni eggs in bladder walls secrete proteolytic enzymes damage to the

distal colon.

Mortality due to Schistosomiasis occur due to bleeding from ruptured oesophageal varicose which treated by injection of Sodium Valporate.

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Adult wormAdult worm

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Schistosoma CoupleSchistosoma Couple

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Diagnostic StageDiagnostic Stage* Schistosoma haematobium :- - Eggs found in urine of urinary Schistosomiasis patients. - Oval egg with terminal spine.

Diagnostic StageDiagnostic Stage* Schistosoma mansoni:- - Eggs found in stool of intestinal Schistosomiasis patients. - Oval egg with lateral spine.

Infective StageInfective Stage* Schistosoma cercaria (forked tail).* Found in fresh water.* Penetrate the skin of human upon

contact with water containing it.

Intermediate hostIntermediate hostSchistosoma haematobium Bulinus

truncatus

Schistosoma mansoni Biomphlaria alexandria

Drugs used in elimination of Drugs used in elimination of wormsworms

(Praziquantel)(Praziquantel) It is drug of choice for all Trematodes &

Cestodes except Fasciola species & hydated sand.

The nervous system of Trematodes and Cestodes is not completely studied. However Praziquantel was found to increase the calcium ion influx inside the worm muscle causing prolonged spasms for the worm; leading to spastic paralysis & death of the worm.

This action not observed on Nematodes, insects or mammalians.

Praziquantel is very safe, taken as a single or divided dose according to the worm type.

Dose is calculated according to the patient weight.

Praziquantel is swallowed, not chewed; as it is very bitter in taste.

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Praziquantel is very safe, taken as a single or divided dose according to the worm type.

Dose is calculated according to the patient weight.

Praziquantel is swallowed, not chewed; as it is very bitter in taste.

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