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Trematoda

Dr. Mohieddn Abdul-Fattah

Trematodes According to Habitat

Intestinal Trematodes:1. Heterophyes

Liver trematodes:

1. Fasciola.

Lung trematodes:1. Paragonimus.

Blood trematodes:

1. Schistosoma

Heterophyes heterophyes

Final host: Man, dogs

and cats

Habitat : between villi in

small intestine

Diagnostic stage: mature

egg in stool.

I. Biology

II. Epidemiology

Geographical distribution: Egypt around Borollosand Menzella lakes , Palestine, Europe and Far East.

Transmission:

1. Intermediate host (I.H.): Pirenella conica is 1st I.H.

and Bolty and Boory fish are 2nd I.H.

2. Reservoir hosts: dogs and cats act as final reservoirhosts.

3. Infective stage: Encysted metacercaia in fish

muscles

4. Mode of infection: Ingestion of insufficiently cooked

or under salted fish infected with Encystedmetacercaria

Clinical picture1. Mild infection is almost asymptomatic

2. Heavy infection induces local intestinal

inflammation and intermittent diarrhea

3. The small eggs may be inoculated into the

blood vesels and migrate to heart and

brain resulting in embolic manifestations.

4. Myocarditis and neurological

complications


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IV. Diagnosis

Detection of eggs in

stool. Egg charcteristics:

1.30 x 15 m,

2.oval, thick shelled,

3.yellowish brown,

operculated

4.mature (contains

developed larva

[miracidium]).

V. Treatment

Praziquantel; 25 mg/kg/8h PO for one day

VI. Control

Adequate salting and cooking of fish and

snail control.

Proper disposal of human waste and

eradication of stray dogs.

Mass examination and treatment of

fishermen and health education

Fasciola hepatica and F. gigantica

I. BIOLOGY

Man, sheep and cattle act as

final hosts.

Habitat in the final host: The

biliary tracts of the liver.

Diagnostic stage: Immature egg

in stool.

Lymnaea snail

Fasciola egg

Fasciola hepatica

Simple tailed cercaria

E. m etacercaria

ongrass

II. Epidemiology Geographical distribution: Egypt

and sheep and cattle raisingcountries.

Transmission:

1. Intermediate host (I.H.): Lymnaeais 1st I.H. and vegetable is 2nd I.H.

2. Reservoir hosts: Sheep and cattleact as final reservoir hosts

3. Infective stage: Encystedmetacercaria

4. Mode of infection: Ingestion of rawvegetable contaminated withencysted metacercaria


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III. Clinical picture

Acute fasciolitic hepatitis during the

migratory phase in liver. fever, eosinophiliaand allergic features.

Chronic biliary fascioliasis jaundice and

haematobilia anaemia. anaemia Fascioliticpharyngitis (Halzoun) caused by the

presence of adult in the pharynx after eating

infected raw sheep liver infectd with adults..

IV. Diagnosis Detection of eggs in

stool. Direct and conc.

Egg charcteristics:

1. thin walled,

2. 140 x 70 m,

3. ovoid,

4. yellowish brown,Operculated,

5. immature (does notcontain developed larva[miracidium]).

Indirect diagnosis

Serodiagnosis

(especially. during

invasive stage)

IFAT (T.S of adult

worm) or ELISA (ES

antigens).

Imaging: CT -

sonography

V. Treatment

Triclabendazole (10 mg/kg PO for one

dose) or Mirazid.

VI. Control1. Adequate washing of vegetable.

2. Mass treatment of Reservoirs.

3. Sanitations of slaughter houses.

4. Control of snails.

5. Proper disposal of human waste.

Paragonimus westermani

Final host: Humans,

dogs, cats, rodents and

pigs.

Habitat: Encapsulated

in the bronchioles of the

lung

Diagnostic stage:

immature eggs passed

in feces and sputum.

I. Biology

Adult

Egg in sputum


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II. EpidemiologyDistribution: worldwide but more

confined in oriental countries such asJapan.

Reservoir hosts: Dogs, cats, rodentsand pigs.

Intermediate hosts: 1st IH snail;Semisulcospira or Thiara and 2nd

fresh water cructaceans.

Infective stage: Encystedmetacercaria in gills and muscles ofcrustaceans (crabs).

Mode of infection: ingestion ofencysted metacercaria inundercooked crustacean.

III. Host Parasite Relationship Early symptoms cough

with blood tinged

sputum.Low grade fever

Difficult to distinguishfrom pneumonia andtuberculosis.

Ectopic sites mayinclude: abdominalwall, heart, lymphnodes and nervoussystem.

T.S. of lung containing

encapsulated adult

Eggs in m. LN with granulomas

abundant with esosinophils

IV. Diagnosis

Clinical picture with

eosinophila in

endemic areas.

Detection of eggs in

sputum or feces.

Serology for ectopicsites DIG or ELISA.

Imaging: plain x-ray.

V.Treatment

Praziquantel; 25mg/kg/8h PO for 2 days

Bithionol ; 20 mg/kg/12h Po daily for 14 ds.

VI.Control Health education.

proper cooking of crabs and crayfish .

Schistosoma mansoni & S. hematobium

BIOLOGY

Man only acts as final hosts.

Habitat in the final host:

Inf. mesenteric veins draininnig largeintestines in S. mansoni.

vesical plexus draining urinary bladder in S.hematobium.

Diagnostic stage: mature egg in stool

(S.mansoni) and in urine (S.

hematobium).


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