Table 5 shows diagnostic features of the tapeworms that live in the intestinal tract, along with their typical geographic locations and means of how they are acquired.
Table 5. Tapeworms Living in the Intestinal Tract.| Species and Description | Image of Egg
found in Feces | Can Human Host the Larval Stage? | Geographic Location and Means of Infection |
| Diphyllobothrium latum (Dibothriocephalus latus) Note the small knob at the one end and vague operculum at the other. 55-75 x 40-50 µm | 
(25) | Yes, rarely: plerocercoid larva | Circumpolar regions of the world (including northern regions of US). Adult acquired by ingesting plerocercoid larva in flesh of fish; larval form acquired by ingesting crustaceans containing procercoid larva. |
| Hymenolepis nana Note the hooklets in the center and polar filaments in the outer portion 30-50 µm | 
(26) | Cysticercoid larva can develop in villus of intestines and then develop into an adult, leading to a hyperinfection of adult tapeworms. | Worldwide. Adult develops when human ingests the cysticercoid larva in insects. |
| Hymenolepis diminuta Note the hooklets and no filaments in the outer portion. 70-85 x 60-80 µm | 
(27) | No | Worldwide. Adult develops when human ingests the cysticercoid larva in insects. |
| Taenia saginata Note the circular shape and thick egg wall. 30-35 µm | 
(28) | No | Worldwide. The adult tapeworm develops in humans when they consume beef containing the cysticercus larva. |
| Taenia solium Indistinguishable from T. saginata |
(28) | Humans can be accidental hosts of the cysticercus larva if they consume the eggs. | Worldwide. Adult develops when human ingests the cysticercus larva when consuming pork. The cysticerus larva can develop in humans by consuming eggs, or through reverse peristalsis. |
| Echinococcus spp. | Egg not found in humans because they only host the larval form.
| Humans are accidental hosts to the larval form, the hydatid cyst. | Worldwide, especially in rural grazing areas (since ungulates are often the intermediate host and dogs are often the definitive hosts). |
| Dipylidium caninum Contains packets of eggs. Individual eggs are 35-40 µm; often are seen in packets as in this image. | 
(29) | No | Worldwide. Human develops adult tapeworm when they accidentally consume a flea containing the larva. Dogs and cats are the usual definitive hosts. |
25. DPDx. "Diphyllobothriasis - Figure J: Diphyllobothriid egg in an unstained wet mount." CDC.gov, 14 May 2019, https://www.cdc.gov/dpdx/diphyllobothriasis/index.html
26. DPDx. "Hymenolepiasis - Figure E: Egg of H. nana in an unstained wet mount. In this image, the polar filaments in the space between the oncosphere and outer shell are clearly visible." CDC.gov, 13 Dec 2017, https://www.cdc.gov/dpdx/hymenolepiasis/index.html
27. DPDx. "Hymenolepiasis - Figure E: Egg of H. diminuta in an unstained wet mount of concentrated stool. Image taken at 400x magnification." CDC.gov, 13 Dec 2017, https://www.cdc.gov/dpdx/hymenolepiasis/index.html
28. DPDx. "Taeniasis - Figure B: Taenia sp. egg in unstained wet mounts." CDC.gov, 18 Dec 2017, https://www.cdc.gov/dpdx/taeniasis/index.html
29. DPDx. "Dipylidium caninum - Figure D: D. caninum egg packet in wet mount." CDC.gov, 10 Jul 2019, https://www.cdc.gov/dpdx/dipylidium/index.html
