Phylum Platyhelminthes, Order Cestoda Flashcards

Question

What are the main features of Echinococcus granulosus?

Answer 1

Prevalent in Humans and in Aus Adults --> smaller (echinococcus are smaller) only contains 6-7 proglottids. The last proglottid is the only gravid --> but is very long and could be longer than half the length of the worm. DH is the dog, wolf, dingo, etc (carnivorous canids) Within the SI (adults) Eggs are brown, striated, hexacanth embryo with 6 hooks - indistinguishable from Taenia Hydatid larval stages --> contains a germinal layer with brood capsules (contain protoscoleces) and a laminated layer. The larval stage is surrounded by an adventitial layer. Cyst filled with hydatid fluid. Can also produce sterile cysts - no protoscoleces Larval host = humans, located in the liver and lungs (hydatid cysts)

Answer 2

DH = carnivorous canids IH = wide range - Domestic cycle - domestic species - Sylvatic cycle - wild species DH shed gravid proglottids / eggs in the faeces IH (humans, etc) become infected by ingesting hexacanths with food and water Humans- infected by ingestion of eggs with manipulation of DH (adhere to coats of dogs), ingestion of veggies, plants, etc contaminated with eggs or drinking water contaminated with eggs by the faeces of infected carnivores After the eggs are ingested, oncosphere hatches in stomach and duodenum. Oncosphere uses hooks to move in the IH and travels to the liver and lungs --> forms small cyst which grows slowly forming hydatid. DH become infected after ingestion of organs containing fertile cysts. Within DH, protoscolices develop and mature within the SI within 4-6 weeks.

Answer 3

``` DH = foxes IH = rodents and humans ``` Lifecycle is mostly sylvatic --> not present in Australia.

Answer 4

The scolex does not contain rostellum and hooks Reproductive system are single or double in each segment Eggs have a pyriform apparatus - wraps around embryo Insects and mice are IH Some contain lappets

Answer 5

Anoplocephala perfoliata --> horses Anoplocephala magna --> horses Moniezia expansa --> ruminants Moniezia benedeni --> ruminants

Answer 6

Scolex contains 4 suckers, 4 lappets, no rostellum, no hooks. Proglottids are wide and thin (short) In horses within the ileo-caecal junction Eggs are D shaped, external envelope is thick, hexacanth embryo is enclosed by large pyriform apparatus.

Answer 7

``` Infects horses No lappets No rostellum No hooks Infects horses Located in SI ```

Answer 8

IH = oribatid mites Horses become infected when mites containing cysticercoid larvae are ingested with the pasture. Cystercercoid larvae are released and grow into adults within the ileo-caecal junction / SI. Gravid proglottids break during passage through horses LI and the EGGS are shed in the faeces. Eggs are consumed by the mites in the pasture --> cysticercoid larvae fevelop in 2-4 months within in IH --> horses infected after ingestion of mites.

Answer 9

Located in Ruminants within the SI Scolex doesn't contain rostellum or hooks, proglottids are wider than longer. Have 2 sets of reproductive organs --> 2 genital pores. Eggs are triangular in M. expansa, or square in M benedeni Hexacanth embryo is enclosed by the pyriform apparatus.

Answer 10

Similar to Anoplocephala species. IH = forage mites Ruminants shed proglottids / eggs in the faeces, eggs ingested by IH , cysticercoid are formed in the body cavity of mites. DH get infected by ingesting infected mites on the pasture. Moves to the SI where they mature

Answer 11

Most common tapeworm in dogs Hosts --> dogs, cats, humans, fox Located in SI Rostellum is retractable with more hooks than normal (3-5 rows) Each proglottid has 2 sets of reproductive organs --> 2 genital pores Gravid proglottids resemble cucumber seeds with up to 150 egg capsules inside each proglottid. The embryophore is not striated - contain hexacanth embryo (6 hooks). Within egg capsules.

Answer 12

IH = flea Proglottids / eggs pass in faeces or spontaneously out of the anus --> causes puritis and scooting Eggs are ingested by the larvae of fleas. Cysticercoid larvae develop synchronously with the metamorphis of the flea. DH ingests adult fleas containing the Cysticercoid larvae.

Answer 13

Hosts - birds Located in jejunum IH = fly

Answer 14

Hosts - birds Located in duodenum IH = earthworms

Answer 15

Rostellum and suckers provided with hooks Infects birds Located in duodenum Very small IH = snails and slugs ingection of the DH is through ingestion of the infected IH

Answer 16

``` Causes nodules in the intestinal wall Rostellum and suckers contain hooks infect birds Located in SI IH = ants Infection if via ingestion of infected ants ```

Answer 17

Known as false tapeworms Scolex provided with 2 grooves called bothria Uterus contains an opening --> eggs shed while they are produced Eggs are operculated and are not developed when laid --> no gravid proglottids Contain 2 IH in the lifecycle. No rostellum, no suckers Eggs released --> develop into coracidium where the operculum opens and the procercoid larvae develops within the 1st IH, the plerocercoid larvae develops within 2nd IH and then moves into the DH within the SI.

Answer 18

Is a pseudophyllidea Adults located in SI of dog, cat and fox Known as the zipper worm as genital pore is obvious Eggs are yellow, asymmetrical, operculated Procercoid larvae develop in copepods Plerocercoid larvae locatedin wide range of hosts (amphibians, reptiles, bird, etc)

Answer 19

Complex Uterus has an opening --> operuclated eggs released through uterine pore, exit in faeces into environment Eggs move into the water, coracidiu forms in egg and hatches --> gets ingested by copepods (1st IH) --> forms into procercoid. The infected copepods are then ingested by the second IH (any vertebrate except fish) and develops into plerocercoid. The plerocercoid of the 2nd IH can also be ingested by another vertebrate (PH) but do not mature. The 2nd IH / PH are ingested by the DH (dogs / cats) --> the plerocercoid larvae develop into adult tapeworms within the SI.

Answer 20

Human health --> sparganosis Infection with the plerocercoid larvae in humans cause sparganum Can be infected by: - Drinking water that contains copepods infected with procercoid larvae - Ingesting raw meat from frogs, snakes, birds or mammals containing plerocercoid larvae - Pressing flesh of infected frog to ulcers, wounds or eyes (Asian practice)