Fascioliasis Overview and Impact

Fascioliasis

• Fascioliasis is a parasitic disease caused by Fasciola hepatica and Fasciola gigantica.
• These parasites infect herbivores but can accidentally infect humans.
• The parasites are Platyhelminthes (flatworms), specifically Trematoda (flukes).
• Three species infect humans: Fasciola hepatica, Fasciola gigantica, and Fasciolopsis buski (lives in the small intestine).

Morphology of the Adult

• Adult flukes are leaf-shaped.
• The fluke has an oral sucker and a larger ventral sucker.
• The male reproductive system begins with two branched testes in the middle of the body.
• The female reproductive system includes a branched (lobed) ovary.

Life Cycle

• The parasite lives in the bile ducts of humans and herbivores (definitive hosts).
• Eggs pass with bile to the intestine and are expelled in feces.
• In water, the egg develops into a miracidium (a free-swimming stage).
• The miracidium infects a snail (intermediate host) Lymnaea cailliaudi or L. truncatula.
• Inside the snail, the parasite develops through sporocyst, rediae, and cercariae stages.
• Cercariae leave the snail and settle on vegetation.
• Encysting forms metacercariae, an infective stage.
• Humans become infected by consuming food contaminated with encysted metacercariae.
• The cyst dissolves in the intestine, and the young worm migrates to the liver via the peritoneal cavity and reaches the bile ducts.

Mode of Infection

• Humans become infected by ingesting freshwater plants or water contaminated with metacercariae.
• A subtype called Pharyngeal fascioliasis occurs by eating raw infected liver.

Important Points

• Definitive host: herbivorous animals and humans.
• Infection site: bile ducts
• Intermediate host: Lymnaea cailliaudi.
• Infective stage: encysted metacercaria.
• Diagnostic stage: eggs in stool.
• Mode of infection: ingestion of encysted metacercaria.
• Infection route: oral

Clinical Features

• Acute phase (fluke migration through the liver): abdominal pain, hepatomegaly, fever, vomiting, diarrhea, eosinophilia.
• Chronic phase (adult fluke within the bile ducts): biliary obstruction, inflammation, liver rot.

Laboratory Diagnosis

• Microscopic identification of eggs in stool.
• Eggs can be detected in stool or in material obtained by duodenal or biliary drainage.

Control & Prevention

• Treat infected animals.
• Control snail populations.
• Avoid eating raw vegetables before washing them.
• Avoid drinking contaminated water.
• Avoid eating raw liver.

Explore the parasitic disease Fascioliasis caused by Fasciola hepatica and Fasciola gigantica. This quiz covers its geographic distribution, morphology, and impact on humans and herbivores. Test your knowledge and learn about this significant health concern.