Morphology - Table 10

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Table 10
Differential Morphology of the Diagnostic Stages of Helminths Found in Humans: Tapeworm Gravid Proglottids

Species	Size	Appearance of Uterus	Other
Taenia solium	12 mm in length x 5-7 mm wide.	Central "stem" or trunk with 7-13 main lateral branches on each side.	Usually on surface of fecal material. May be in short chains of 2-3 proglottids.
Taenia saginata	16-20 mm long × 5-7 mm wide.	Central "stem" or trunk with 15-20 main lateral branches on each side.	Usually on surface of fecal material. May be single detached proglottids.
Diphyllobothrium latum	2-4 mm long × 10-12 mm wide. Broader than long.	Coiled into a rosette appearance.	Occasionally, portion of worm may be passed. Egg is usual diagnostic stage.
Dipylidium caninum	12 mm long × 3 mm wide. Pumpkin-seed shape; tapers at each end.	Uterus not visible. Proglottid filled with capsules containing eggs.	Proglottids may be passed singly or in chains. Often resemble rice grains in stool.
Hymenolepis nana	0.2-0.3 mm long x 0.8-0.9 mm wide. Broader than long.	Uterus not visible. Proglottid filled with eggs.	Proglottids usually disintegrate in the intestinal tract and are rarely seen in stools. Egg is usual diagnostic stage.
Hymenolepis diminuta	0.7-0.8 mm long × 3-4 mm wide. Broader than long.	Uterus not visible. Proglottid filled with eggs.	Proglottids usually disintegrate in the intestinal tract and are rarely seen in stools. Egg is usual diagnostic stage.

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