Fasciola hepaticaFasciola hepatica sheep liver flukesheep liver fluke

liver flukeliver fluke

Fasciola hepatica• Common name: The sheep liver fluke• Habitat: Bile duct of liver.• Route of infection: Man eat aquatic plants with

encysted metacercariae.• Definitive host: Usual host sheep, infects liver of

various mammals, including humans.• Intermediate host: Fresh water snails.• Infective stage: Encysted metacercariae on

vegetations.• Diagnostic stage: Eggs in stool specimen.• Disease: Fascioliasis.

Fasciola hepatica adult

Morphological characteristics• 2-3 cm.• Has conical projection• Oral and ventral sucker.• Pharynx.• Branched caecum.• Coiled uterus• Genital formula : O ( ovary) T ( Testis) T ( Testis)

Fasciola hepatica Eggs

• Unembyonated.• Thin egg shell.• operculated. • 130-150 X 63-90 um.• Diagnostic stage

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egg capsule with emerging miracidium of Fasciola hepatica

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Life cycle

• The parasite browses on liver tissue for a period of up to 5-6 weeks and eventually finds its way to the bile duct where it matures into an adult and begins to produce eggs.

• Up to 25,000 eggs per day per fluke can be produced, and in a light infection, up to 500,000 eggs per day can be deposited onto pasture by a single sheep.

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Pathology and clinical symptoms.

• Most of the damage results from worms are migrating through the liver parenchyma feeding on liver cells and blood

• Worms in the bile ducts cause inflammation and edem• The triad of fever, hepatomegaly, and eosinophilia.• Symptoms and signs are associated with biliary obstruction • Acute epigastric pain, and jaundice are common.

diagnosis

Laboratory diagnosis: finding large operculated eggs in the feces.

Intestinal fluke

Fasciolopsis buskiFasciolopsis buski

Fasciolopsis buski• Common name: The large intestinal fluke• Habitat: Lumen of small intestine.• Route of infection: Man eat uncooked plants with encysted

metacercariae.• Definitive host: Mainly human, other hosts; pigs and dogs.• Intermediate host: Fresh water snails.• Infective stage: Encysted metacercariae on vegetations.• Diagnostic stage: Eggs in stool specimen.• Disease: Fasciolopiasis.

Fasciolopsis buski adult

Morphological characteristics• 2-7x 0.5-2 cm.• Oral and ventral sucker.• Esophagus .• Unbranched caecum.• Coiled uterus.• Branched ovary.• Branched Testes.• Genital formula : O ( ovary) T ( Testis) T ( Testis)

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This photo is to compare the sizes of Fasciolopsis buski

(left) and Fasciola hepatica (right)

Fasciolopsis buski Eggs

• Unembyonated.• Thin egg shell.• Inconspicuous.

operculum. • 130-150 X 63-90 um

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Clinical features

• Most infections are light and asymptomatic. In heavier infections, symptoms include diarrhea, abdominal pain, fever, ascites, and intestinal obstruction.

Laboratory diagnosis:operculated eggs and some times the adults are

found in the feces.

Lung Fluke

Paragonimus westermaniParagonimus westermani

Paragonimus westermani

• Common name: The Lung Fluke.• Habitat: Encapsulated in Lungs.• Definitive host: Human, also other mammals.• First intermediate host: Water snail.• Second intermediate host: Crustaceans,Crabs.• Infective stage: Encysted metacercariae.• Diagnostic stage: Eggs in sputum or feces.• Disease: Paragonimiasis.

morphology

• 7 – 12 x 4 – 6 mm.• Oral & Ventral Suckers• Unbranched caecum.• Pharynx.• Coiled Uterus ( black color)• Genital formula: O T T

Paragonimus westermani

Paragonimus westermani Eggs

• 80-120 x 50-60 um• Large, thick, dark shell.• Prominent operculum at

the broad end.• Thick posterior end.• Unembryonated.

Egg Miracidio

RediaI Redia II

Cercarias Metacercarias

Life Stages

Paragonimus westwermani

• Pathology: Adults in lungs stimulate inflammatory response

resulting in granulomas. Movement of worms to heart or brain causes death.

• Symptoms: Chronic cough , difficulties breathing , sputum

with blood. When moves to brain, can cause blindness,

paralysis , disequilibrium , epilepsy.

DIAGNOSIS• based on detection of characteristic eggs in sputum, or

stool,• serology helpful; standard test is complement fixation

(CF) – has advantage to detect rapid decline in antibody levels