Life cycle of Taenia saginata (beef tapeworm)
and Taenia solium (pork tapeworm).
The life cycles of these two cestodes involve alternate larval and adult stages in two hosts: intermediate and definitive. Adult worms attach to the intestine by means of the scolex and absorb nutrients from the host. A ribbonlike chain of segments called proglottids form, each of which contains male and female sexual organs and produce ova. Proglottids or ova are passed in the feces sporadically; multiple examinations may be required for diagnosis. Intermediate hosts (cattle, pigs) ingest the eggs and develop larval cysts in their tissues. Cysts are eaten by the definitive host in uncooked meat; they mature into tape-worms in the digestive tract. Humans may also ingest T. solium eggs, which may travel to brain or muscle to form cysticeri (cysts).
Taenia saginata (ou)
Scoleces of Taenia saginata (Figure H) and Taenia solium (Figures I and J).
Gravid proglottids of Taenia saginata (Figures D and E) and Taenia solium (Figures F and G)
Taenia saginata. Gravid proglottid.
Taenia saginata adult worm. The adult in Figure K is 12 feet long.
Taenia saginata. Adult tapeworm.
Taenia saginata proglottids
Histopathologic features of Taenia saginata in appendix