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Liver Fluke (Fascioliasis) - Coggle Diagram
Liver Fluke
(Fascioliasis)
Epidemiology
Environment
Infective Fasciola larvae (metacercariae) are found in contaminated water—typically, stuck to (encysted on) water plants or, potentially, floating in the water—such as in marshy areas, ponds, or flooded pastures.
Agent
Fasciola hepatica
Morphology: large broad and flat body, cephalic cone, two shoulders, converging margins,
simple medial branches of intestinal caecal, small oral and central suckers, smaller in size
Has a wide distribution, almost entire continent except for Antartica
Fasciola gigantica
Morphology: less prominent shoulders, parallel margins, medial branches are T or Y shaped, larger in size
Has a more limited distribution, covers tropical regions of Africa, Middle East, and Asia
More pathogenic than
F. hepatica
Intermediate form of
Fasciola
Distribution: Japan, Vietnam, Korea
Are hybrid species
Existence of hybrid species could result in more pathogenic
Fasciola
isolates
Intermediate Hosts
F. gigantica
: Lymnaea rubiginosa (freshwater snail)
commonly found in artificial drainage, irrigation canals, slow running streams, ponds, clear and turbid water where there are water plants such as
Ipomoea sp.
(water spinach)
Host
Breed: Cattle, sheep, goat
Found in liver and biliary passages of the host
Lesion: liver fibrosis, liver cirrhosis, biliary cirrhosis
Differential Diagnosis
Hepatic lipidosis
Flukes
Hepatic abscess
Control & Treatment
CONTROL
1.Prevent parasite build-up in the environment.
Prevent pasture contamination.
Avoid heavily contaminated pasture.
Use of resistant animals (resistant animals, genetic control)
TREATMENT
Salicylanilides (eg: Closantel, Niclosamide)
weaken worms by ATP depletion.
Benzimidazoles (eg: Albendazole, Mebendazole)
starve the parasite by preventing glucose uptake
Clinical Sign
Anorexia and reduce growth rate
Loss of weight and milk production
Chronic diarrhea or faeces may be normal/hard
Bottle jaw, jugular pulsation and icteric mucous membrane
Diagnosis
Fecal examination - detect typically elliptical eggs, less distinct embryonic mass,operculum and yellow in color
Serology - ELISA, AGPT
Pathophysiology
Liver flukes infections (hepatic function)
Carbohydrate metabolism
Glucose not obtain directly from diet
Obtain from hepatic conversion of three-carbon precursor into glucose
Also convert two-carbon units derived from gut into ketone for energy substrate for tissues other than brain
Hepatic carbohydrate metabolism is impaired
Protein metabolism
Infected sheep with 1000 metacercariae the relative rate of albumin synthesis declined during theparenchymal stage but increased during the biliary stage
No evidence for cattle
Steroid metabolism
Principle site of steroid metabolism via mixed-function oxidase system reduced
Possibility of decrease rate of clearance of exogenous testosterone in postpubertal rams
Failure of fluke-infected livestock to maintain pregnancy
Bile flow and composition
Flow and composition of bile would be altered
Due to the fluke activity, there will be a leakage of erythrocyte into the bile duct, hence rate of iron excretion in the bile increased
This is due to, hyperplasia of the bile duct which increases bile flow and hence allowing entry of the flukes into the bile duct and commencement of blood feeding