Cestodes Flashcards
What are cestodes
Tapeworms
What is the scolex
Small, whole head of a tapeworm
What is the rostellum
It is what tapeworms use to attach to the host gut - suckers or hooks
What are proglottids?
segments of the tapeworms body
Gravid proglottids are bags of eggs
They break off the end of the worm and pass out of gut into environment
How do tapeworms reproduce?
They are hermaphrodites
As they grow they mate with themselves, generating fertilised eggs and dropping them off and passing out your arse
How does tapeworm infection reach humans
Eating cow or pig meat that is infected with eggs - raw or undercooked
What is the life cycle of a tapeworm
- man is the only definitive host
- cattle and pigs ingest eggs that contain onchosphreres
- eggs hatch and onchospheres burrow through gut wall, invade striated muscle and develop into cystericerci
- infected eat eaten by humans
How long do cysticerci last
several years
What is diphyllobothrium latum
Echinococcus - small group of tapeworms
- very small
- only has 3 ploglottids
- human is intermediate host, found in fish
What is the life cycle of echinococcus
- Eggs ingested by animal/man
- hatch in gut and release onchos which burrow through gut wall and enter circulation
- go to liver, brain and lungs
- develop cysts producing protoscolices and daughter cysts
- infection proceeds when cysts are eaten
- you can have slow growing cysts and be unaware, but once burst protocolises release and can cause a fatal shock
How do you achieve the adult worm in echinococcus
Through eating an animal that has the cysts
How do onchosperes cause infection in echinococcus?
- they traverse the gut wall via blood and lymph tissues, to lodge and develop into metacestodes
- bound by a thin cellular layer - germinal layer filled with fluid - into a cyst
- the outer layer has extraC matrix 3-5mm thick
- coats itself in factor H, a complement inhibitory factor from the host which stops complement working
what is the name of the dwarf tapeworm
Hyemnolepis Nana
