Fasciola hepatica sheep liver 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)

Fasciola hepatica Eggs Unembyonated. Thin egg shell. operculated. 130-150 X 63-90 um. Diagnostic stage

egg capsule with emerging miracidium of Fasciola hepatica

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.

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 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)

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

Clinical features Laboratory diagnosis: 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 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.

Life Stages Egg  Miracidio RediaI Redia II Cercarias Metacercarias

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