Magnified 500X, this photomicrograph revealed the presence of a Fasciolopsis buski trematode egg that was found in an unstained formalin-preserved stool sample. F. buski are the largest intestinal flukes found parasitizing human beings. These flukes inhabit Asia and the Indian subcontinent, especially in areas where humans raise pigs, and consume freshwater plants.
Most infections are light and asymptomatic. In heavier infections, symptoms include diarrhea, abdominal pain, fever, ascites, anasarca and intestinal obstruction.
Microscopic identification of eggs, or more rarely of the adult flukes, in the stool or vomitus is the basis of specific diagnosis. The eggs are indistinguishable from those of Fasciola hepatica.