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DPDx is an education resource designed for health professionals and laboratory scientists. For an overview including prevention and control visit www.cdc.gov/parasites/fasciolopsis.

Fasciolopsiasis

[Fasciolopsis buski]

Egg of F. buski in unstained wet mounts 200x magnification

Egg of F. buski in unstained wet mounts 200x magnification


Adult fluke of F. buski.  Image contributed by Georgia Division of Public Health.

Adult fluke of F. buski. Image contributed by Georgia Division of Public Health.

Causal Agents

The trematode Fasciolopsis buski, the largest intestinal fluke of humans.


Life Cycle

Life cycle of Fasciolopsiasis

Immature eggs are discharged into the intestine and stoolThe number 1. Eggs become embryonated in water The number 2, eggs release miracidia The number 3, which invade a suitable snail intermediate host The number 4. In the snail the parasites undergo several developmental stages (sporocysts The number 4a, rediaeThe number 4b, and cercariae The number 4c ). The cercariae are released from the snail The number 5 and encyst as metacercariae on aquatic plants The number 6. The mammalian hosts become infected by ingesting metacercariae on the aquatic plants. After ingestion, the metacercariae excyst in the duodenum The number 7 and attach to the intestinal wall. There they develop into adult flukes (20 to 75 mm by 8 to 20 mm) in approximately 3 months, attached to the intestinal wall of the mammalian hosts (humans and pigs) The number 8. The adults have a life span of about one year.

Geographic Distribution

Asia and the Indian subcontinent, especially in areas where humans raise pigs and consume freshwater plants.

Clinical Presentation

Most infections are light and asymptomatic. In heavier infections, symptoms include diarrhea, abdominal pain, fever, ascites, anasarca and intestinal obstruction.

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  • Page last reviewed November 29, 2013
  • Page last updated November 29, 2013
  • Content source: Global Health - Division of Parasitic Diseases and Malaria
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