Balantidium coli may invade into extraintestinal sites, especially in patients with defects in host defenses.


Extraintestinal sites for balantidiosis:

(1) appendix

(2) liver

(3) lung (possibly by inhalation of aerosolized cysts from manure, by hematogenous spread, or by an enteric fistula)

(4) vagina and/or uterus in females (either by migration or rectovaginal fistula)

(5) urinary bladder

(6) peritoneal cavity (following bowel perforation in severe intestinal disease) and ascites fluid


Because of the rarity of extraintestinal spread the trophic ciliates may be seen but go unrecognized.


A person with pulmonary disease may have negative studies for cysts or trophic ciliates in the stool. These patients may have inhaled cysts or have colonization of the pharyngeal region.


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