Intestinal Tapeworm (Cestode)

Abstract

Adult tapeworms, known as cestodes, reside in the small intestine where they feed off the host’s food. They are attached to the intestinal wall by a structure called the scolex, which is connected to a chain of segments known as proglottids that make up the strobila. Each proglottid contains both male and female reproductive systems and are categorized as immature, mature, or gravid based on their stage of development. Gravid proglottids are found at the end of the strobila and contain a fully developed uterus filled with eggs, which is often used for identification purposes. The eggs and the scolex can also be used to identify the specific species of the tapeworm. Cestodes have complex life cycles that involve intermediate and definitive hosts. In some cases, humans can be the definitive hosts with adult worms living in the intestine (Diphyllobothrium latum, Taenia saginata, Hymenolepis diminuta, and Dipylidium caninum), while in other cases humans can serve as both the definitive and intermediate hosts (T. solium and H. nana). Tapeworms have been documented as far back as 1500 BC and are among the oldest known human parasites. The prevalence of human intestinal tapeworms is not well understood, but it is estimated that millions of people are infected with various species of tapeworms. While the presence of adult tapeworms in the intestine is not typically life threatening, infection with larval tapeworms can be serious and potentially fatal.