MSD Manual

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Life Cycle of the Pork Tapeworm

Life Cycle of the Pork Tapeworm

  • 1. People may become infected when they eat raw or undercooked pork containing cysts of tapeworm larvae (called cysticerci).

  • 2. In the intestine, the cysticerci mature into adult tapeworms and attach themselves to the wall of the intestine.

  • 3. Adult tapeworms produce segments (called proglottids) that bear eggs. The proglottids may release the eggs or detach from the rest of the tapeworm and travel to the anus.

  • 4. The eggs, proglottids, or both are passed in stool.

  • 5. Pigs or, less often, people become infected by consuming the eggs or proglottids (for example, in food contaminated with human stool).

  • 6. After the eggs are consumed, they hatch in the intestine and release spheres (called oncospheres) that penetrate the wall of the intestine.

  • 7. The oncospheres then travel through the bloodstream to muscles and to the brain, liver, and other organs, where they develop into cysts.

Life Cycle of the Pork Tapeworm