Fasciola hepatica Life Cycle Quiz

Infective Stage

• The infective stage of Fasciola hepatica is the metacercaria, a larval stage.
• Metacercariae are found encysted on aquatic vegetation, such as watercress.
• Humans or other mammals become infected by consuming contaminated water plants.

Intermediate Host

• The intermediate host for Fasciola hepatica is a mollusk, typically a species of Lymnaea.
• The parasite enters the mollusk, developing into a cercaria.

Development in the Intermediate Host

• Once inside the mollusk, the parasite undergoes development.
• This development leads to the production of free-swimming cercariae.
• The cercariae penetrate and encyst on water plants, transforming into metacercariae.

Penetration of Definitive Host

• The metacercariae are ingested by a definitive host (e.g., sheep, cattle, humans).
• Following ingestion, the metacercariae excyst in the small intestine.

Excystment and Migration

• The excystment occurs in the small intestine.
• The young fluke migrates through the intestinal wall.
• It then travels through the peritoneal cavity to the liver.

Development in the Liver

• The flukes migrate through the bile duct system of the liver.
• They begin to mature and grow.
• During this stage, the flukes develop their characteristic body shape.

Adult Flukes

• Adult flukes are hermaphroditic, meaning they possess both male and female reproductive organs.
• Once mature, they begin mating and producing eggs.

Egg Production and Release

• Adult flukes produce numerous eggs within the bile duct system.
• These eggs are released into the bile ducts.
• The eggs eventually pass into the feces.

Egg Fate and Lifecycle Continuation

• Eggs excreted in the feces, if released into suitable aquatic environments, hatch.
• The eggs release miracidia, which infect intermediate hosts (mollusks).
• The parasite continues its life cycle repeating the process.

Test your knowledge on the life cycle of Fasciola hepatica, focusing on its infective stages and the role of intermediate hosts. This quiz covers the development in mollusks and the process of how the parasite infects definitive hosts. Understand the transformations from metacercariae to adult flukes.