释义 |
DictionarySeedwarfEncyclopediaSeeHymenolepiasisDwarf Tapeworm The only human tapeworm with no intermediate host Epidemiology It is most common in warm, dry climates; infection is by direct transmission, often among families, and in institutions; the eggs hatch in stomach and small intestine, penetrate villi and metamorphose into cercocysts; recalcitrant infections are maintained by autoinfection Treatment Praziquantel, niclosamidetapeworm (tap'worm?) Any of the species of flatworms of the class Cestoda, phylum Platyhelminthes; all are intestinal parasites of humans and other animals. A typical tapeworm consists of a scolex, with hooks and suckers for attachment, and a series of a few to several thousand segments, or proglottids. New proglottids develop at the scolex, so that a worm is actually a linear colony of immature, mature, and gravid proglottids; adult worms range from less than an inch to 50 ft or more, depending on the species. The terminal proglottids, which contain fertilized eggs, break off and pass from the host in the feces. The eggs develop into small, hooked embryos, which, when ingested by the proper intermediate host (usually another vertebrate such as a pig), develop into encysted larvae (cysticerci) in the muscle tissue. Humans acquire tapeworm infestation by eating undercooked meat that contains the cysticerci. See: Diphyllobothrium latum for illus; TaeniaSpecies of medical importance are Diphyllobothrium latum, Echinococcus granulosus, Hymenolepis nana, Taenia saginata, and T. solium. See: cysticercosis; cysticercus; hydatid; taeniasis SymptomsSymptoms are often absent, but abdominal discomfort, bloating, or changes in bowel habits may be present. If tapeworms are very numerous, they may cause intestinal obstruction (but this is rare). Some species of tapeworms may cause severe disease: Echinococcus can cause life-threatening cysts in the liver or pericardium; Taenia solium can encyst in the brain and cause seizures or strokelike symptoms. armed tapewormTaenia solium.beef tapewormTaenia saginata.broad tapewormDiphyllobothrium latum.dog tapeworm1. Dipylidium caninum.2. Echinococcus granulosus.dwarf tapewormHymenolepis nana.fish tapewormDiphyllobothrium latum.heart-shaped tapewormDiphyllobothrium cordatumhydatid tapewormEchinococcus granulosus.mouse tapewormHymenolepis nana.pork tapewormTaenia solium.rat tapewormHymenolepis nana.unarmed tapewormTaenia saginata.FinancialSeeDwarf |