Cestodes Flashcards
Feature difference between trematodes and cestodes
blind ended gut = trematodes
no gut = cestodes
general features of cestodes
- head =scolex
- suckers +/- armed hooks
- solid or hollow
- rostellum -armed or unarmed & retractable or permenent
- neck = differentiating zone
- body segments = proglottids
- mature proglottids at the end (reproductively mature)
- no gut
- mainly just reproductive system
- metamorphosis
- alternating hosts (cyst and adult forms)
- cyst in IH (metacestode larval stage- in tissues ; pathogenic)
- adult tapeworm in DH (taenia) - intestine, mostly non pathogenic
What are the 2 orders of Eucestoda
pseudophyllidea (aquatic LC; 2 IH)
Cyclophyllidea (terrestrial LC ; usually 1 IH)
What are the 2 groups of cyclophyllideans?
- non taeniids (herbavors, omnivores or carnivores as DH)
- taeniiids (always carnivorous DH) - important socioeconomically
What are 2 species of pseudophyllidea that are of veterinary importance
Diphylloborthrium latum
Spirometra erinacei
What are the species of Cyclophyllidea that are of veterinary importance?
Non Taeniids
- Dipylidium caninum
- Anoplocephala perforliata
- Moniezia expansa & M. benedeni
- Hymenolepis
- Choanotaenia
- Amoebotaenia
- Raillietina
- Davainea
Taeniids
- Taenia & Echinococcus
What is the general LC of Pseudophyllidea?
- aquatic
- DH = carnivore/omnivore (fish eating animals)
- egg excreted via uterine pore
- coracidium (ciliated oncosphere)
- IH
- Procercoid >> 1 IH = invertebrate - water flea or cyclops
- Plerocercoid >> 2 IH or PH = vertebrate - tadpole, water snakes
General LC of Non Taeniid Cyclophyllidea
- terrestrial
- DH = carnivore, omnivore, herbivore
- egg from ruptured proglottid (apolysis)
- oncosphere
- cysticercoid >> IH = invertebrate/arthropod **fleas
General Life Cycle of Taeniid Cyclophllidea
- terrestrial
- DH: carnivore
- egg via apolysis
- oncosphere
- IH: mammalian *mice/rats
- cysticercus
- coenurus
- hydatid
What is the significance of larval cestodes in the intermediate host?
- in tissues of mammals
- economic losses
- liver and heart condemnation
- decrease pproductivity
- human health
What is the clinical significance of adult cestodes in the DH
Mostly in SI and mostly NOT pathogenic
- except horses (cecum impaction = colic) or birds or cats (dxa & vomitting)
What is the difference in reproductive systems bw pseudophyllidea and cyclophyllidea
pseudophyllidea -zipper worms
- aquatic
- 1 set of repro organs per proglottid
-
central uterine & genital pore
- eggs shed into feces
cyclophyllidea
- terrestrial
- 1-2 sets of repro organs/proglottid
- proglottids shed into feces - then rupture
- lateral genital pore
proglottid morphology - L 11 slide 14
What are the egg differences bw pseudophyllidea and cyclophyllidea?
pseudophyllidea
- aquatic- thin operculate
- ciliated embryophore
- eggs shed from the uterine pore and pass in the feces
cyclophyllidea
- terrestrial - thick shell
- eggs are released by rupture of the proglottid
BOTH have hexacanth embryophore
egg types - L11 slide 17
metacestode (larva) morphology - L11 slide 18
Pseudophyllideans (Spirometra/Diphylobothrium)
- Procercoid
- Plerocercoid
Cyclophyllideans (non taeniids)
- Cysticercoid (Dipyliidium/ Hymenolepis)
- double walled bladder cyst
- IH = arthropod (flea) or another invertebrate
Cyclophyllideans (taeniids)
- large fluid filled cycsts - “ bladder worms”
- Cysticercus - protoscolex (T. hydatidgena) & (strobilocercus of Taenia taniaeformis)
- Coenurus - protoscoleces (T. multiceps)
- Hydatid - (Echinococcus)
metacestode morphology L 11 slide 19
metacestode morphology L11 slide 20
Metacestode morphology L 11 slide 21
Feature differences between Pseudophyllidian and Cyclophyllidian cestodes
Lecture 11 Slide 23
Pseudophyllidean features & facts (rapid fire 5 things)
- 2IH - aquatic
- procercoid - invertebrate IH
- plerocercoid - vertebrate IH
- DH - carnivore/omnivore
- scolex w/ bothria
- hold onto host w/vacuum
- central uterine pore
- operculate, thin shelled eggs shed in feces
- proglottids detach in chains
- diphyllobothrium
- spirometra
Diphylobothrium LC
- eggs passed in feces
- coracidium ingested by copepod (1st IH)
- procercoid ingested by freshwater fish (2nd IH)
- procercoid > pleurocercoid in fish
- fish ingested by DH
- seal, human, dog, cat, bear, penguin
- Adult tapeworm in SI
Where in the world do you see diphyllobothriasis?
- alaska, canada, scandinavia, russia, japan and emerging in S. America
- ingestion of pleurocercoid in raw/pickled marine + freshwater fish
What is the public health concern of diphyllobothria? (clin signs, control and treat)
- tapeworm up to 10m in SI
- clinical signs
- asymptomatic or milk abdo discomfort to severe dxa and cramps
- B12 deficiency > pernicious anaemia
- control
- cook for freeze fish >24h @20*
- treat
- praziquantel













