Fasciola hepatica

TREMATODES-2-

Fasciola hepatica


Fasciola hepatica and F. gigantica are bile duct parasites of domestic ruminants. In their life cycle freshwater snails act as intermediate host Humans become accidentally infected when they eat plants to which infectious parasite stages (metacercariae) adhere
Fasciola hepaticaF. hepatica is a flattened,leaf-shaped parasite about 2–5 cm long and at most1 cm wide.

Fasciola hepatica egg

Life cycle of Fasciola hepatica
●Adult liver flukes parasitize in the bile ducts. ● They produce large golden brown, operculated eggs that are shed by the bile duct-intestinal tract route. ● Under favorable conditions, a ciliate larva, the miracidium, develops in the egg within a few weeks. ● The miracidia then hatch and penetrate into freshwater snails where they transform into sporocysts.

Life cycle of Fasciola hepatica

● After formation of further asexual reproductivestages, tailed cercariae develop and swarm outof the snails into the open water. ● They soon attach to plants and encyst, transforminto infective metacercariae, which are theningested with vegetable food of their definitivehosts (sheep,cattle,human) ● Eating watercress contaminated with metacercariae is one of the sources of infection for humans.

Life cycle of Fasciola hepatica

● The juvenile liver flukes hatch from the cyst inthe small intestine, penetrate the intestinal wall,and migrate through the peritoneal cavity to theliver. (sheep,cattle,human) ● After migrating through the hepatic parenchymafor about six to seven weeks, the parasites finallyreach the bile ducts, in which they developto sexual maturity. (sheep,cattle,human) ● Egg excretion begins two to three months(sheep,cattle,human)


Life cycle of Fasciola hepatica

Fasciola hepaticaEating watercress contaminated with metacercariae is one of the sources of infection for humans.


Diagnosis of Fasciola infection . ●The manifestations to be expected during the migration phase of the liver fluke include mainly leukocytosis, eosinophilia, and a rise in liver specific serum enzymes. ● Detection of eggs in stool or duodenal fluid is not possible until at least two to three months . ● Other diagnostic tools include detection of serum antibodies and of coproantigen in stool.

Treatment of Fasciola infectionThe drug of choice is triclabendazole, the infection can be avoided by not eating raw watercress and other plants that may be contaminated with metacercariae.