Balantidium coli causes balantidiasis. It is associated with animal reservoirs, especially pigs.
In symptomatic patients, it causes diarrhea and abdominal pain. In more serious cases, the parasite is invasive and can perforate the colon, which can produce stools with blood or mucus. Perforation may facilitate bacterial spread and complicating infections.
Tetracycline can be an effective treatment.
- General pathogenesis of Balantidium coli***
Basic morphologic features: Oblong shape with several cilia, which beat in unison to provide motility, and macro- and micro- nuclei, which are helpful diagnostic clues.
Cysts are ingested in contaminated food or water. Trophozoites are released and colonize the large intestine, where they multiply.
Some trophozoites will encyst, others may invade the colon wall, leading to perforation.
Trophozoites and cysts are excreted in the feces.
As we've learned elsewhere, the trophozoites cannot survive outside the host, but the cysts, thanks to their protective coverings, survive and are ingested by the next host.
