Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content


Causal Agent:

Balantidium coli, a large ciliated protozoan parasite.

Life Cycle:

Balantidium coli

Cysts are the parasite stage responsible for transmission of balantidiasis The number 1 . The host most often acquires the cyst through ingestion of contaminated food or water The number 2 . Following ingestion, excystation occurs in the small intestine, and the trophozoites colonize the large intestine The number 3 . The trophozoites reside in the lumen of the large intestine of humans and animals, where they replicate by binary fission, during which conjugation may occur The number 4 . Trophozoites undergo encystation to produce infective cysts The number 5 . Some trophozoites invade the wall of the colon and multiply. Some return to the lumen and disintegrate. Mature cysts are passed with feces The number 1 .

Life cycle image and information courtesy of DPDx.