Cal - Cestodes Flashcards
A feature of cestodes that’s often very useful in identification?
The number/type of their attachment structure (hooks/suckers/teeth/plates)
Cestodes AKA?
tapeworms
Chain of proglottids?
Strobila
What’s the rostellum?
Pointed end of scolex that has points of attachment… can be useful in identification
Most cestode eggs are NONoperculated and contain a ____ embryo…
hexacanth
Most cestodes are nonoperculated with a hexacanth embryo… What’s the exception?
Diphyllobothrium latum (unembryonated and operculated)
Infective stages of taenia?
As oncospheres developing into cysticerci in muscle
refer to CDC life cycle graphic
What’s the cattle-associated taenia? What about the pig-associated taenia?
T. saginata = cow
T. solium = pig
Diagnostic stage of taenia?
Eggs/gravid proglottids in FECES and shed into the environment
Taenia can infect by?
And how does taenia reside in the human body?
Humans ingest undercooked meat.
Taenia scolex attaches to intestine (adults in the small intestine)
Taenia adults produce proglottids which eventually detach from tapeworms and exit as?
Exit in the stool as eggs within gravid proglottids
Both taenia are worldwide… Saginata persists in US due to?
Consumption of rare steak
Solium is more prevalent in poor communities where humans live close to?
pigs
Taenia asiatica found?
ASIA!
Korea, China, Taiwan, Indonesia, Thailand
Saginata taeniasis SSx
Mild abdominal ssx
Striking feature = active/passive passive of proglottids
Occasionally -> appendicitis/cholangitis from migration proglottids
Solium taeniasis SSx…
Less frequently symptomatic than saginata
Mainly the passive of progottids
However…?
Most important feature of solium taeniasis?
RISK FOR DEVELOPING CYSTICERCOSIS
Egg and proglottid identification is diagnostic for taenia spp but not possible during first 3 months (i.e., prior to adult stage). Furthermore EGGS of taenia are indistinguishable from Echinococcus… So?
Microscopic ID of gravid proglottids
(or if possible, scolex)
Be careful when processing specimens… CYSTICERCOSIS…
Sup with taenia saginata’s scolex?
FOUR cup-muscular shaped suckers
NO HOOKLETS
You can distinguish saginata from solium by counting uterine branches in proglottid… how many in each?
Solium: 7-13
Saginata: 15-30
Infection of humans/pigs with larval stages of T. solium called?
Cysticercosis
Taenia solium can/cannot cause autoinfection?
CAN
T. solium can occur in environments AWAY from pigs as humans can shed the eggs the eggs in their feces…
bummer
Greatest clinical concern for T. Solium?
Cerebral cysticercosis (neurocysticercosis) = seizures, mental disturbances, focal neurologic deficits from space-occupying intracerebral lesions (potential for sudden death)
Extracerebral cysticercosis can cause?
Ocular, cardiac, or spinal lesions
Asymptomatic subQ/calcified IM nodules also possible
Cystericercosis must be demonstrated in tissue. So if eggs/proglottids are ONLY in feces, what we got?
Likely only taeniasis
However, due to autoinfection, serological evaluation is recommended to evaluate for cystircercosis
Solium scolex?
Four suckers
HOOKLETS (does saginata have hooklets?)
Fish or broad tapeworm?
Largest human tapeworm?
Diphyllobothrium
Diphyllobothrium intermediate hosts?
crustaceans and FRESHwater fish
Diphyllobothrium larval form?
coracidium
Infective stage of Diphyllobothrium?
as the pleroceroid larva (in freshwater fish)
Diagnostic stage of Diphyllobothrium?
Unembryonated eggs passed in feces
What’s unique about Diphyllobothrium?
Scolex with two leaf-shaped suckers
Bothria, or lance-shaped
Diphyllobothrium found where?
Northern Hemisphere (Europe, North America, Asia) and South America
CEVICHE…
(however infected fish can be transported/consumed elsewhere)
SSx are rare (unless proglottids migrate). However, Diphyllobothriasis can lead to a major deficiency of?
B12…
PERNICIOUS Anemia
Diphyllobothrium… Specific diagnosis of EGGS in the stool. Describe Diphyllobothrium egg…
Numerous eggs that are OPERCULATED with a KNOB SHELL on the other end
Diphyllobothrium proglottids are?
uterine structure resembling a ROSETTE
Human echinococcosis AKA?
hydatidosis/hydatid disease
Most frequently encountered form of echinococcosis?
Echinococcus granulosus, causing cystic echinococcosis
echinococcosis granulosis found where?
worldwide, wherever there are grazing dogs
echinococcosis multilocularis found?
Northern hemisphere
echinococcosis vogeli/oligarthrus found?
CentAm/SouthAm
echinococcosis infective stage?
Embryonated egg shed in feces
echinococcosis diagnostic stage?
Hydatid cyst in liver/lungs/etc.
echinococcosis physical characteristics?
Scolex with four suckers
TWO rows of hooklets
Slow-growing, tumor-like space occupying structure resulting from echinococcosis larval form?
Hydatid cyst
Structures on the wall of of hydatid cyst?
Brood capsules
tapeworms can develop protoscolices here
When echinococcosis daughter cysts/brood capsules disintegrate/liberate protoscolices… what we got?
hydatid sand
echinococcosis granulosis can be silent for years… upon cyst enlargement, affected organ will produce corresponding symptoms
And just like that, BAM! Organ problems
can affect liver, lungs, brane, boan, hart
echinococcosis multilocularis mainly affects?
the liver, slowly
echinococcosis vogeli mainly affects?
Liver, slowly
echinococcosis diagnosis
RADIOLOGIC EXAMINATION (hydatid presence)
with help from clinical/serologic findings
Dwarf tapeworm?
Hymenolopsis nana
Hymenolopsis nana egg?
SIX hooked embryo (hexacanth)
Polar filaments
Hymenolopsis nana Scolex…
FOUR suckers
Crown of hooklets
Hymenolopsis nana infectious stage?
Embryonated egg ingested from contaminated food/water/hands/feces
CAN ALSO AUTOINFECT (from feces or by remaining in intestine)
AUTOINFECTION
Hymenolopsis nana diagnostic stage?
Embryonated egg in feces
Hymenolopsis nana larvae can develop in human intestine as….
cystercercus
Hymenolopsis dimunita infectious stage?
Cystercerci in body cavity of insect that gets INGESTED
diagnostic stage of Hymenolopsis dimunita?
Egg passed in feces
Hymenolopsis dimunita scolex?
NO HOOKS
Hymenolopsis dimunita egg?
Larger than H. nana
Bile stained
NO polar filaments
Hymenolopsis dimunita requires what to reach infective cystercercoid stage?
larval insects/mealworms
Most common of all cestode infections?
Hymenolopsis nana
(worldwide)
Hymenolopsis dimunita is worldwide, though less frequent
Hymenolopsis dimunita and nana are often asymptomatic but H. nana can cause?
weakness, HA, ab pain, diarrhea
Pumpkin seed tapeworm?
Diplydium caninum
Diplydium caninum infective stage
Adult flea harboring the infective CYSTICERCOID
Diplydium caninum diagnostic stage?
When the proglottids release their egg packets
Diplydium caninum found?
Worldwide
Diplydium caninum, clinically?
Proglottids are MOBILE (can be mistaken for other larvae – maggots)
Mild GI, but most striking feature is passage of proglottids
Diplydium caninum accidental (or purposeful, I assume?) ingestion of what?
Flea
Spirometra sp infective strage?
PLEROCERCOID larve
Fish/reptile/amphibian (second intermediate host) ingests infected crustacean
Spirometra diagnostic stage?
Unembryonated eggs passed in feces
Spirometra infection?
Sparganosis
Spirometra found?
Worldwide, but predominantly in SE Asia
Sparganosis resulting in ocular disease/periorbital edema is often assocaited with?
Poultice use from frog/snake flesh
Interesting technque…
Sparganosis/spirometra diagnosis?
Recovery of sparganum from tissue
