Cestodes- Taenia Flashcards
What are the hosts of Taenia saginata (aka beef tapeworm)?
definitive host: humans only
intermediate: host: cattle only
What is the cysticercus?
tapeworm stage where the scolex is invaginated inside and where it will evaginate. soybean-like in shape. common to all Taenia species
What is particular about the Taenia saginata scolex?
have four suckers and lacks hooks
Which organs do the mature proglottids of Taenia saginata have?
both male and female organs
How can Taenia saginata gravid proglottids be identified?
have 15 or more branches on each side of the uterus
Why are the eggs of Taenia saginata not used for diagnosis?
all eggs of parasites from the Taeniidae family have identical eggs
Will Taenia saginata develop if a cow ingests an egg?
yes
Will Taenia saginata develop if a cow ingests a cysticercus?
no
Will Taenia saginata develop if a human ingests an egg?
no
Will Taenia saginata develop if a human ingests a cysticercus?
yes
What are the hosts of Taenia solium (aka pork tapeworm of humans)?
definitive host: humans only
intermediate host: pigs only
What makes Taenia solium more dangerous than Taenia saginata?
humans can be accidental intermediate hosts
What is particular about the Taenia solium scolex?
has 4 suckers and 2 circles of hooks
How can Taenia solium gravid proglottids be identified?
have 14 or more branches on each side of the uterus
What is the diagnostic stage for Taenia solium?
the gravid proglottids
What is cysticercosis?
When humans ingest eggs or become auto-infected. can cause neurocysticercosis (cysticercus infection in the brain) with symptoms of seizures, mental disturbances,
focal neurologic deficits, and signs of space‐occupying intracerebral lesions
How can cysticercosis be diagnosed?
need to demonstrate cytircercus in the involved tissue. Taenia solium infection indicates taeniasis, not cysticercosis
How can cysticercosis be treated?
a combination of anti-parasitics and anti-inflammatories used. surgery used in case of eye infections, not responsive to drugs, or to reduce brain edema
How can the adult Taenia solium worms be treated?
praziquantel. increases the worm’s permeability to calcium ions
What are the hosts of Echinococcus granulosa?
definitve host: dogs and other Canidae
intermediate host: sheep + other herbivores, humans
Which variety of Echinococcus granulosa infects native Canadian’s?
Echinococcus granulosa var. canadiensis aquired from moose and caribou
What is hydatid disease?
aka. echinococcosis. when the juvenile stage of the parasite develops into a large, fluid-filled cyst (hydratid cyst)
How can Echinococcus granulosa be distinguished from other tapeworms?
one of the smallest tapeworms. scolex has 4 suckers with hooks. has only scolex, neck, one immature proglottid, one mature proglottid, and one gravid proglottid at a time.
egg cannot be distinguished from Taenia species
Which stage of Echinococcus species cause echinococcosis?
the larval stage
Which species causes cystic echinococcosis?
Echinococcus granulosus
Which species causes alveolar echinococcosis?
Echinococcus multilocularis
Where does Echinococcus granulosus occur?
worldwide, mostly in rural grazing areas
Where does Echinococcus multilocularis occur?
northern hemisphere
What is the pathology of cystic echinococcosis?
symptoms only occur when cysts become very large. cysts rupturing causes fever, anaphylactic shock, cyst dissemination. mostly liver and lung involvement, but also brain, bones, heart
What is the pathology of alveolar echinococcosis?
affects the liver as a slow-growing tumor. causes abdominal pain, biliary obstruction, occasionally metastatic lesions in lungs and brain
How can echinococcosis be diagnosed?
ultrasonography or other imaging techniques supported with serologic tests
What is the treatment for echinococcosis?
surgery to remove cyst may not be 100% effective, so albendazole may be used to prevent recurrence.
Albendazole causes degenerative alterations in the tegument and intestinal cells of the worm by binding to tubulin, which inhibits its assembly into microtubules.
