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December 2, 1905


JAMA. 1905;XLV(23):1739-1740. doi:10.1001/jama.1905.02510230039006

The infusorium, Balantidium coli, as the cause of human intestinal infection, was described first by Malmsten of Stockholm in 1857. Since then, something like 117 cases have been recorded, according to the recent summary by Strong,1 and there seems all reason to believe that this parasite may give rise to diarrhea, sometimes serious and often persistent. It is an oval-shaped, ciliated organism, from.07 to 0.1 mm. in length by from.05 to.07 mm. wide, capable of motion and of some change in form; reproduction may take place in three ways, viz., by division, the most frequent; by budding, and by conjugation. It may undergo encystation.

Balantidium coli occurs with great frequency in the colon and cecum of the hog, which is regarded as its proper host, and in which it appears to be a harmless commensal. It is not known how human infection takes place; water, in which the organism