Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

Biology

Causal Agents:

The cestodes (tapeworms) Taenia saginata (beef tapeworm) and T. solium (pork tapeworm). Taenia solium eggs can also cause cysticercosis.

Life Cycle:

Life Cycle of Taenia saginata and Taenia solium

Taeniasis is the infection of humans with the adult tapeworm of Taenia saginata or Taenia solium. Humans are the only definitive hosts for T. saginata and T. solium. Eggs or gravid proglottids are passed with feces The number 1; the eggs can survive for days to months in the environment. Cattle (T. saginata) and pigs (T. solium) become infected by ingesting vegetation contaminated with eggs or gravid proglottids The number 2. In the animal's intestine, the oncospheres hatch The number 3, invade the intestinal wall, and migrate to the striated muscles, where they develop into cysticerci. A cysticercus can survive for several years in the animal. Humans become infected by ingesting raw or undercooked infected meat The number 4. In the human intestine, the cysticercus develops over 2 months into an adult tapeworm, which can survive for years. The adult tapeworms attach to the small intestine by their scolex The number 5 and reside in the small intestine The number 6. Length of adult worms is usually 5 m or less for T. saginata (however it may reach up to 25 m) and 2 to 7 m for T. solium. The adults produce proglottids which mature, become gravid, detach from the tapeworm, and migrate to the anus or are passed in the stool (approximately 6 per day). T. saginata adults usually have 1,000 to 2,000 proglottids, while T. solium adults have an average of 1,000 proglottids. The eggs contained in the gravid proglottids are released after the proglottids are passed with the feces. T. saginata may produce up to 100,000 and T. solium may produce 50,000 eggs per proglottid respectively.

Life cycle image and information courtesy of DPDx.

 
Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd.
    Atlanta, GA 30333
  • 1-800-CDC-INFO
    (1-800-232-4636)
    TTY: 1-888-232-6348
    Hours of Operation
    8am-8pm EST/ Monday-Friday
    Closed Holidays
  • Contact CDC-INFO
  • Page last reviewed: January 10, 2013
  • Page last updated: January 10, 2013
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC-INFO