Intestinal Cestodes continued Clinical Microbiology Review 253
GRAVID INTERMEDIATE DIAGNOSTIC
CESTODE SCOLEX PROGLOTTID OVUM HOST TRANSMISSION STAGE OTHER
Hymenolepis
nana
Dwarf tape-
worm. Adult
2.5–4 cm
long. Most
common
tapeworm.
Only tape-
worm without
intermediate
host. Mainly
in children.
Growth
retardation.
Wider than
long. Uterine
branches
obliterated by
eggs. 3 ovoid
irregularly
spaced testes.
Diamond-
shaped.
4 suckers.
Single row of
hooklets
around short
rostellum.
Round. 40 μm.
Colorless. 2
distinct walls.
Slight bulge at
each pole of
inner wall
with 4–8
hair-like polar
filaments.
Ingestion of
eggs in feces of
infected
mice/rats
None Ova in feces
(From Leventhal R, Cheadle RF. Medical
Parasitology: A Self-Instructional Text,
5th ed. Philadelphia: FA Davis; 2002:47.)