Intestinal Ciliates Clinical Microbiology Review 243
CILIATE TROPH CYST TRANSMISSION PATHOGENIC? OTHER
Balantidium coli Only ciliate pathogenic
to humans. Largest
protozoan of humans.
Common in pigs.
Ovoid. Usually 40–50 μm, Ingestion of cyst
but can reach 200 μm.
Covered with cilia. Funnel-
shaped cytostome. Macronu-
cleus & micronucleus.
Vacuoles. Rapid rotary
motion.Round. 45–65 μm.
Thick refractile cell
wall. No cilia.Yes