18 Questions
What is the definitive host of H. diminuta?
Humans or rodents
What is the intermediate host of H. diminuta?
Arthropods
How is H. diminuta transmitted to humans?
By eating contaminated food such as cereals, grains, and grain-based foods.
What happens when eggs of H. diminuta are ingested by an arthropod intermediate host?
They release onchospheres and develop into cysticercoid larvae.
Describe the autoinfection process of H. diminuta.
Eggs release their onchospheres that penetrate the intestinal villi and continue the life cycle without exiting the body.
What do adults of H. diminuta produce and release?
Gravid proglottids and eggs
Describe the morphology of H. diminuta eggs.
Round or slightly oval with a striated thick outer membrane and a thin inner membrane. Oncospheres have six hooks.
What is the difference between the oncospheres of H. diminuta and H. nana?
H. diminuta oncospheres have six hooks and a smooth or slightly granular space between the two membranes, while H. nana oncospheres have six hooks and polar filaments filling the space between the oncosphere and outer shell.
How can both H. diminuta and H. nana eggs be detected?
Both eggs can be detected in stool specimens.
What is the difference in the scolex morphology between H. nana and H. diminuta?
H. nana scolex has four suckers and a rostellum with hooks, while H. diminuta scolex has four suckers but no hooks.
Explain the life cycle of H. diminuta.
The intermediate hosts, such as insects, ingest the eggs. Larvae develop in the intermediate host and then are ingested by rodents. Rodents are then eaten by insects, completing the life cycle.
What are the symptoms of hymenolepiasis?
Most often asymptomatic. Heavy infections with H. nana can cause weakness, headaches, anorexia, abdominal pain, and diarrhea.
What is the definitive host of H. diminuta?
Humans or other fish-eating animals
Identify the first intermediate host of H. diminuta.
Freshwater crustaceans
Which host ingests the ciliated coracidia of H. diminuta?
Crustaceans (first intermediate host)
What form do the eggs of H. diminuta pass in human feces?
Unembryonated
What is the infective form of H. diminuta found in raw or undercooked freshwater fish?
Plerocercoid larvae
In which host does the plerocercoid larvae of H. diminuta develop tissues?
Freshwater larger fish (3rd paratenic host)
Test your knowledge on the life cycle of cysticercoid larvae and symptoms of hymenolepiasis. Learn about how the larvae attach to the intestinal wall, mature into adults, and produce gravid proglottids. Discover the symptoms of hymenolepiasis and how heavy infections can lead to weakness and headaches.
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