Week 5: Cestodes Flashcards
Which tapeworm life cycle stage is infective for the intermediate host?
Eggs
What are the parts of an adult tapeworm?
:)
What are the parts of a tapeworm egg?
:P
What kind of tapeworm stages can you use for stool samples?
- Proglottids
- Whole tapeworms
Which tapeworm stage can you use for concentration in the lab?
Eggs
What are the two Taenia species and what are their primary non-human hosts?
- Taenia saginata: beef
- Taenia solium: pork
Describe the lifecycle of Taenia species. Include infective and diagnostic stages
Infective stage: Embryonated eggs ingested by human host
Diagnostic stage: Adults in small intestine
Describe Taenia species’ eggs
- Round
- 30-43 microns
- thick cell wall with radial striations
- inside of embryonated egg 6-hooked oncosphere (refer to image)
Which Taenia parts are found in the feces?
- eggs
- scolex
- proglottids (segmented part)
What is the scolex?
It’s the head of the tapeworm
Since can’t look at eggs to differentiate between Taenia species, what do you look at instead?
Uterine branches of gravid proglottids. Solium has fewer branches while saginata has more branches
Identify the genital pores of the proglottid and the Taenia species
How do you distinguish between the scolex of Taenia solium and saginata?
T. solium has rostellum with a double row of hooklets. But both have 4 suckers
Which human disease is Taenia solium associated with? Signs/symptoms caused by what?
Cystercosis
Cysticerous stage disseminated throughout body causes muscle, brain, eye, and CNS symptoms
What are the 2 Hymenolepsis spp?
- nana dwarf tapeworm
- diminuta rat tapeworm
Describe the Hymenolepsis nana life cycle. Include infective and diagnostic stages
- Infective: embryonated egg ingested by humans in contaminated food, water, or hands. Also embryonated egg in feces is infectious
- Diagnostic: Embryonated egg in feces
Describe Hymenolepsis nana eggs
- Oval shaped
- 30-50 microns
- Inner membrane with polar filaments
- Oncosphere has 6 hooks
Describe the Hymenolepsis diminuta life cycle. Include infective and diagnostic stages
- Infective stage: Cysticerci in body cavity of insect ingested by rodent or human
- Diagnostic stage: Eggs passed in feces
Describe Hymenolepsis diminuta eggs
- Size = 70-85 microns
-Round or slightly oval - Striated outer membrane
- Thin inner membrane
- Zero polar filaments
- Oncosphere has 6 hooks
Describe the fish tapeworm aka Diphyllobothrium latum life cycle. Include infective and diagnostic stages
- Infective stage: Human ingests raw or undercooked, infected fish
- Diagnostic stage: Unembryonated eggs passed in feces
Where is Diphyllobothrium latum found?
Found worldwide where pickled or raw freshwater fish is eaten
Describe the Diphyllobothrium latum egg
- Unembryonated
- Operculated (refers to the end of the egg having a lid- or cap-like cover)
- Bile stained
- Size= 58-76 by 40-50 microns
- Knoblike structure on the end opposite the operculum
Which stages of Diphyllobothrium latum are ID’d for lab diagnosis?
- scolex
- proglottid
- egg
Does pickling readily kill Diphyllobothrium latum?
No. Does not readily destroy eggs. Cooking does kill the eggs
What is the animal host of Echinococcus granulosis?
Dogs
Sorry, Scooby Doo
Describe the life cycle of Echinococcus granulosis? Include infective and diagnostic stages
- Infective stage: Embryonated egg in feces
- Diagnostic stage: Hydatid cyst in liver, lungs, brain, bone, heart
Which disease is Echinococcus granulosis? associated with?
Hydatid cyst disease
What does the Echinococcus granulosis larval stage produce? Describe
Hydatid cysts
Contain fluid, brood capsules, and daughter cysts in which the scolices (plural of scolex) of potential tapeworms are formed. Material inside called hydatid sand
What determines hydatid cyst size
The organ it grows in. It’ll just keep growing until it can’t anymore
What are two types of flukes/trematodes (in reference to their reproductive aspect). Where do they live?
- Hermaphroditic adults: live in intestine, lungs, and liver
- Unisexual adults: live within blood vessels (aka blood flukes)
What is the genus of the blood flukes?
Schistosoma
Describe the general trematode life cycle
Ain’t no way I’m typing all this :)
Describe the Paragonimus westermani life cycle. Include infective and diagnostic stages
- Infective stage: humans ingest inadequately cooked or pickled crustaceans containing metacercariae (cysts)
- Diagnostic stage: unembryonated eggs in stool or sputum (cuz they’re lung flukes). Harder to find in stool though. Better chance finding them in the lungs
Describe the Paragonimus westermani egg
- Size: 80-118 microns by 48-60 microns
- oval, flattend operculum
- slight shoulders
- unembryonated
- Thickened area opposite the operculum
Describe the Fasciolopsis buski life cycle. Include infective and diagnostic stages
- Infective stage: Metacercariae on water plant ingested by humans or pigs, causing infection
- Diagnostic stage: Unembryonated eggs passed in feces.
What is the size of Fasciolopsis buski adults?
3-7 microns
Describe Fasciolopsis buski eggs
- Size = 130-140 by 80-85 microns
- Bile stained
- Inconspicuous operculum
- Unembryonated
- **Identical to Fasciola hepatica so report as Fasciola/Fasciolopsis **
Describe the Fasciola hepatica life cycle. Include infective and diagnostic stages
- Infective stage: Metacercariae on water plant ingested by human, sheep, or cattle
- Diagnostic stage: Unembryonated egg passed in feces
Describe Fasciola hepatica eggs
- Size= 130-150 microns by 60-90 microns
- Unembryonated
- Inconspicuous operculum
- Identical to Fasciolopsis buski
Describe the Clonorchis sinensis life cycle. Include infective and diagnostic stages
- Infective stage: Metacercariae in flesh or skin of fresh water fish are ingested by human host
- Diagnostic stage: Embryonated eggs passed in feces
Size of Clonorchis sinensis adults?
6-17 mm
Describe the Clonorchis sinensis egg
- Size - 29-35 microns
- Embryonated
- Flask shaped
- Operculated with prominent shoulders (Darrell underlined this part in the slides(
- Knob at the end opposite the operculum
Describe the Metagonimus yokogawai and Heterophyes heterophyes life cycles. Include infective and diagnostic stages
- Infective stage: Host becomes infected by ingesting undercooked fish containing metacercariae
- Diagnostic stage: Embryonated eggs each with a fully-developed miracidium are passed in the feces
Describe the Metagonimus yokogawai and Heterophyes heterophyes eggs (same features)
- Size - 28-39 microns
- Embryonated
- Operculated with inconspicuous shoulders (Darrell underlined in slides)
- Vase or flask shaped
- Resemble Clonorchis sinensis and Opisthorchis species
True or false: Schistosoma eggs are operculated
False
What is the ONE intermediate blood fluke host?
The snail
How do blood flukes infect humans?
Cercarial penetration of skin
Describe the Schistosoma life cycle. Include infective and diagnostic stages
- Infective stage: cCercariae released by snail into water and free-swimming penetrate human skin
- Diagnostic stage: Passed in feces (mansoni, japonicum, and haematobium) or urine (japonicum or haematobium)
Where do S. mansoni, japonicum, and haematobium mainly live in the human host?
- mansoni: veins of the large intestine
- japonicum: veins of the small intestine
- haematobium: veins of the bladder
Describe Schistosoma mansoni eggs
- Size = 115-175 by 45-75 microns
- Prominent lateral spine
How do you diagnose S. mansoni in the lab?
Fin embryonated eggs in the feces
Describe Schistosoma japonicum egg
- Size = 60-95 by 40-60 microns
- Small, curved spine that can be difficult to see
Describe Schistosoma haematobium eggs
- Size: 110-170 microns by 40-70 microns
- Terminal spine
Practice. Identify the parasite
Taenia spp. egg
ID the parasite
Taenia solium proglottid
ID the parasite
Taenia saginata proglottid
ID the parasite
Hymenolepsis nana egg
ID the parasite
Hymenolepsis diminuta egg
ID the parasite
Diphyllobothrium latum egg
ID the parasite
Echinococcus granulosus hydatid cyst
ID the parasite
Paragonimus westermani egg
ID the parasite
Fasciolopsis buski egg
ID the parasite
Fasciola hepatica egg
ID the parasite
Clonorchis sinensis egg
ID the parasite
Clonorchis sinensis adult
ID the parasite
Metagonimus yokogawai adult fluke
ID the parasite
Metagonimus yokogawai egg
ID the parasite
Heterophyes heterophyes
ID the parasite
Schistosoma mansoni egg
ID the parasite
Schistosoma japonicum egg
ID the parasite
Schistosoma haematobium egg