Presentation is variable and is dependent on size, location, and condition of the cyst.
Extra-intestinal manifestations include cystercercosis (can affect any organ), hydatidosis (can affect any organ but typically the liver and lungs), and neurocysticercosis (affecting the CNS).
Diagnosis is made by stool examination and serology; radiology may be necessary for extra-intestinal manifestations.
Intestinal infection is treated with antihelminthics only, while extra-intestinal infection may require surgical intervention.
Tapeworms refer to parasites of the taxonomic class Cestoda, and include the orders Pseudophyllidea and Cyclophyllidea. They divide their life cycles between two animal hosts. The worms can vary in length from a few millimetres to 25 m, and can contain thousands of proglottids (tapeworm segments).   Adult tapeworms usually possess an anterior scolex (head; plural 'scolices') that may be modified with structures or organelles that attach to the host. Therapy is aimed at the destruction of the scolices, and failure to achieve this will result in regrowth of the tapeworm. When mature, these parasites reside in the intestinal tract of definitive carnivorous hosts, and larval cysts are formed in the intermediate hosts.
Human tapeworms cause intestinal infection when the immature cysticercoid larvae attach to the intestinal mucosa using the scolices, and grow by production of proglottid segments.
Certain cestodes can cause extraintestinal infections. Ingested eggs hatch in the intestines and larva migrate to extraintestinal tissues, where they encyst. Cysts due to Taenia solium within the central nervous system are referred to as neurocysticercosis, and cysts in other locations are termed cysticercosis. Cysts due to Echinococcus granulosus are referred to as cystic echinococcosis or hydatid cysts, and cysts due to E multilocularis are referred to as alveolar echinococcosis.
Assistant Professor of Medicine
Infectious Diseases Fellowship
Baylor College of Medicine
JAS declares that he has no competing interests.
Baylor College of Medicine
AC declares that he has no competing interests.
Dr Jose A. Serpa and Dr Andrew Chou would like to gratefully acknowledge Dr Christina Coyle and Dr Maheen Saeed, previous contributors to this monograph. CC is an author of several references cited in this monograph. MS declares that she has no competing interests.
Chief and Professor of Medicine
Division of Infectious Diseases and International Health
University of Virginia Health System
WAP declares that he has no competing interests.
College of Medicine
University of Malawi
LK declares that she has no competing interests.
PR declares that he has no competing interests.
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