Segments of the Adult Tapeworm

Tapeworm is the common name given to a class of parasitic flatworms that inhabit the digestive tract of vertebrates. They can often be found in pets like dogs and cats but also in livestock and sometimes in humans. Depending on the species, tapeworms can grow from several inches up to 40 feet in length. An adult tapeworm has two main segments, the scolex and the strobila.

  1. Scolex

    • The scolex is the head of the tapeworm. Depending on the species it has either suction cups, hooks or teeth that are used to attach to the intestine wall of its host. The main nerve center is found in the scolex and is known as a ganglion. The head is attached to the neck where new segments called proglottids grow. They push the older segments toward the tail.

    Strobila

    • The body of a tapeworm resembles a thin piece of tape. It is made up of many independent segments known as proglottids, which are collectively called strobila. A tapeworm absorbs nutrients from the food consumed by the host through the membrane. Some flatworms use flame cells, a specialized excretory cell that functions similar to a kidney to remove waste, and these are located in each segment of the strobila.

    Proglottids

    • Each proglottid of a tapeworm is identical. They each contain both male and female reproductive tracts as well as a digestive system. The proglottid fertilizes itself and produces tapeworm eggs. As the tapeworm grows the older proglottids are moved toward the end of strobila, pushed by the new segments grown by the neck. By the stage they reach the tail the proglottid is simply a sac of eggs. It is then detached and excreted by the host.

    Infection

    • While a tapeworm infection doesn't generally cause pain, some people do experience diarrhea, upper abdominal discomfort and a loss of appetite. You can recognize a tapeworm infection by examining the feces. The proglottid segments can be found in the stool of an infected host. They appear as white worms and may move. Oral medication of niclosamide, praziquantel or albendazole can be taken for humans. In the case of pets, refer to your veterinarian.