Flagellates of the Intestinal and Urogenital
Tractscontinued
Clinical Microbiology Review 240
FLAGELLATE TROPH CYST TRANSMISSION PATHOGENIC? OTHER
Giardia lamblia
(also known
asG. intestinalis
orG. duodenalis)
Common in U.S.
Enterotest:
Patient swal-
lows capsule
attached to
string. String
withdrawn
after 4 hr.
Mucus exam-
ined. Antigen
detection.
Pear-shaped. 10–20 μm. 2 nuclei
with large central karyosomes.
4 pairs of flagella. Anterior & ven-
tral sucking disks. 2 axostyles.
2 median bodies. “Old man in
glasses.” Falling leaf motility.
Ovoid. 8–19 μm. Thick
double wall. Cytoplasm
shrinks away from cell
wall. 2–4 nuclei at ante-
rior end. Median bodies &
axostyles.
Ingestion of cyst
in contaminated
water, oral-anal,
pets
Yes
(From Leventhal R, Cheadle RF. Medical Parasitology: A Self-
Instructional Text, 5th ed. Philadelphia: FA Davis; 2002:100.)
(From Leventhal R, Cheadle
RF. Medical Parasitology: A
Self-Instructional Text, 5th
ed. Philadelphia: FA Davis;
2002:100.)
continued...
