Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of many similar units known as proglottids—essentially packages of eggs which are regularly shed into the environment to infect other organisms. Species of the other subclass, Cestodaria, are mainly fish infecting parasites.
Cestoda
Scolex of Taenia solium with hooks and bothria present.
Two proglottids of Taenia solium. This species has 7 to 13 branches of the uterus on each side (above and below in this micrograph).
"Tetraphyllidea": elaborate four-leaved scolex
Parasitic worms, also known as helminths, are large macroparasites; adults can generally be seen with the naked eye. Many are intestinal worms that are soil-transmitted and infect the gastrointestinal tract. Other parasitic worms such as schistosomes reside in blood vessels.
Hookworms attached to the intestinal mucosa
Two pinworms
Processed helminth eggs samples from a dry toilet in Kenya
Analysing for helminth eggs in samples of feces from a dry toilet in Kenya