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Intestinal Cestodes 175

MICROSCOPIC DIAGNOSTIC MICROSCOPIC DIAGNOSTIC

FEATURE FEATURE

General Classification—Cestode (rat General Classification—Cestode (rat
tapeworm) tapeworm egg)

Organism Hymenolepsis Organism Hymenolepsis
diminuta diminuta
Specimen Required Stool specimen Specimen Required Feces
Stage Eggs may be found; Stage Egg
rarely scolex or Size Eggs are differenti-
proglottids
ated from H. nana by
Size The adult tapeworm size, and are gray- to
may reach 20–60 cm straw-colored and
Shape Segmented 50–75 μm
Motility Not demonstrated Shape Eggs possess an inner
membrane but have
Other Features Direct fecal-oral
transmission no polar filaments
H. diminuta lacks the surrounding the
hooks of the rostel- oncosphere as does
lum that H. nana H. nana
exhibits Shell Contains an
envelope-like center
with two thickenings
at opposite ends of
H. diminuta
the structure similar
Ovum Proglottids
to those of H. nana
Other Features Proglottids of
H. diminuta indistin-
Delmar/Cengage Learning of H. nana
guishable from those

DIPYLIDIUM CANINUM

The Dipylidium caninum species of tapeworm some-
times infect humans as an accidental host when fleas are
ingested, a route of infection found mostly in children.
Treatment and Prevention The organism is also called the cucumber tapeworm or
the double-pore tapeworm as the adult proglottids have
Treatment for H. diminuta infections is usually the ad- genital pores on both sides of the tapeworm. D. cani-
ministration of niclosamide, but praziquantel is also a num is a cyclophyllid cestode, an important order that
drug of choice. Prevention entails cleaning areas of food infects mammals afflicted with fleas, including dogs,
storage, rodent control, and sanitary practices in food cats, and the owners of pets, especially children. Pro-
handling and personal hygiene. These practices, how- glottids are pumpkin-shaped and can reach a length
ever, are greatly curtailed in low socioeconomic settings of about 18 in. Eggs are found in characteristic “egg
and in poor countries. clusters” or “egg balls” of 15 to 25 eggs that are passed