Week 5 Flashcards
What are the technical terms for the head, neck, and body of cestodes?
What are the different names of tapeworms in prey vs. predator?
What are the two stages of cestodes?
* Adult in definitive host (DH) (intestine; mostly non-pathogenic)
* Larva (metacestode) in IH (Tissues; pathogenic in vertebrates)
What are the two orders of eucestoda?
Pseudophyllidea (aquatic LC; 2 IHs)
Cyclophyllidea (terrestrial LC; usually 1 IH)
What are the two groups of Cyclophyllideans?
* Non-taeniids (herbivorous, omnivorous or carnivorous DH)
* Taeniids (always carnivorous DH; major socioeconomic importance)
General life cycle of cestodes
Egg passed in faeces–> ingested by IH
**metacestode (larval stage) that causes the infection
What are the genera of Pseudophyllidea (aquatic LC; 2 IHs) that are important?
Diphyllobothrium latum
Spirometra erinacei
** humans, cats and dogs
What are the genera of Cyclophyllideans, Non-taeniids that are important?
* Dipylidium caninum (humans, cats, dogs)
* Anoplocephala perfoliata (horse)
* Moniezia expanza, M. benedeni (cow, sheep)
* Hymenolepis (rodent, chicken, human)
* Choanotaenia, Amoebotaenia, Raillietina, Davainea (chicken)
What are the genera of Cyclophyllideans taeniids that are important?
Taenia and Echinococcus (cats and dogs)
Life cycle patterns via ingestion of Pseudophyllidea (aquatic) vs. Cyclophyllidea (terrestrial)?
Which tapeworm (cestodes) are of human significance?
Anoplocephala perfoliata (horse)
Raillietina, Davainea (chicken)
Morphology of cestodes
* 2-4 suckers +/- armed (aka hooks)
* Rostellum (permanent or retractable)– may contain hooks (aka armed)
Anoplocephala perfoliata (horse) (cestode)
What does an osmoregulatory system have?
What is osmoregulation?
Flame cells
Osmoregulators maintain a more or less stable internal osmolarity by physiological means. Terrestrial animals must osmoregulate because they unavoidably lose water by evaporation and excretion, and replacement water is not always immediately available.
What is the most unique thing about the organ systems in cestodes? What are proglottids?
No gut!!
proglottids- segments
What does the tegument and subtegument of a tapeworm do?
Protection, traction, nutrient absorption, digestion
Reproductive systems of Cyclophyllidea vs. Pseudophyllidea
Cyclophyllidea: proglottids can be filled with eggs, they are alive- pooped out of the host. Dries out, ruptures, and that is how eggs are released. 1 can give rise to 50,000 metacestodes.
Pseudophyllideans: uterine pore- where the eggs pops out. So if you’re doing a faecal float, the chances of finding this egg is close to zero.
Pseudophyllidean tapeworm
Raillietina (chickens)
Which egg is which?
** some of the thick shelled terrestrial can survive for a couple of years in the environment
How likely are you to see Hymenolepis, Taenia, Echinococcus, Anoplocephala, Dipylidium, and Moneizia in faeces?
Uncommon to see in faeces because they are Cyclophyllidea therefore they release segments (proglottids) in faeces, not single eggs. The proglottids have to dry first for the eggs to rupture.
