Fasciolopsiasis FAQs

What is fasciolopsiasis?

Fasciolopsiasis is caused by infection with the intestinal fluke Fasciolopsis buski.

How does one become infected with Fasciolopsis?

People become infected with Fasciolopsis when they eat raw or undercooked aquatic plants that have the organism encysted on them.

Where is Fasciolopsis found?

Fasciolopsis is found in south and southeastern Asia; pigs, as well as humans, are a major reservoir of infection.

What are the signs and symptoms of fasciolopsiasis?

Many people do not have symptoms from Fasciolopsis infection. However, abdominal pain and diarrhea can occur 1 or 2 months after infection. With heavy infections Fasciolopsis flukes can cause intestinal obstruction, abdominal pain, nausea, vomiting, and fever. Allergic reactions and swelling of the face and legs can also occur — and anemia may be present.

How is fasciolopsiasis diagnosed?

The diagnosis is made by finding the flukes or their eggs in the feces or even in vomit.

Can Fasciolopsis be transmitted from human to human?

No, Fasciolopsis is not transmitted directly from human to human. Humans (and pigs) pass eggs in their feces, which develop in water and infect snails as intermediate hosts. After further development, the parasites leave the snail intermediate host and encyst on water plants. Humans become infected as a result of eating these contaminated water plants raw (or undercooked).

Is there treatment for fasciolopsiasis?

Yes, fasciolopsiasis can be treated with prescription medicine taken by mouth, called praziquantel. Praziquantel is approved by the FDA, but considered investigational for this purpose.

How can fasciolopsiasis be prevented?

  • Cook all aquatic plants well before eating them (in boiling water).
  • In endemic areas, prevent fecal contamination (from humans or pigs) of water where aquatic plants are grown. Do not feed raw aquatic plants to pigs.

This information is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the parasites described above or think that you may have a parasitic infection, consult a health care provider.

Page last reviewed: April 1, 2014