Platyhelminths

Question 1

Platyhelminth

Answer 1

Flat worm

Tegument is spines or smooth, body compressed and flat

Digestive system is a blind sac

Hermaphroditic usually

Question 2

Monogenea

Answer 2

Small parasitic fluke on fish, amphibians and turtles

No/ weak oral sucker

Use large posterior organs for attachment

No intermediate hosts- aquaculture

Question 3

Trematodes

Answer 3

All parasitic, endoparasites

Question 4

Digenea, trematodes

Answer 4

Sexual or asexual

2+ hosts and the first is always a snail

2 attachment organs, ceca for digestion and hermaphroditic

Question 5

Flukes

Answer 5

Suck blood

Obstruct ducts and vessels

Egg accumulation

Destroy tissues/ organs via feeding, migration and pressure necrosis

Question 6

Life cycle of flukes

Answer 6

Snail - microcidium- sporocyst- rediae or cercariae

Cercariae leaves snail into environment before becoming metacercaria

Question 7

Sporocyst

Answer 7

Develops in snail and produces radiae or cercariae

Question 8

Rediae

Answer 8

Can be omitted

Question 9

Cercariae

Answer 9

1. Penetrate/ingested by 2nd IH
2. Attach to vegetation
3. Penetrate DH directly

Ways to get to metacercaria

Question 10

Metacercaria

Answer 10

Encyst in environment or transport host

Infects DH and infective stage

Question 11

Schistosomes

Answer 11

Tubular body

Dioecious

No 2nd IH, only 1

Mature in the blood of the DH

Many species pathogenic in humans, cercariae in water to skin

Question 12

Trematode Dx

Answer 12

Sedimentation

Question 13

Cestoda

Answer 13

All parasitic, adults in SI

Muscular and nervous systems

Scolex- attachment organs and proglottids have repro organs

Hermaphroditic

Question 14

Gravid proglottids

Answer 14

Eggs within

Largest size

Question 15

Dipylidium caninum

Answer 15

Rounded proglottids

Question 16

Spirometra mansonoides

Answer 16

Wide proglottids

Question 17

Taeniid tapeworm

Answer 17

Very long and thin

Question 18

Cyclophyllideans

Answer 18

True tapeworms

Scolex can be armed or unarmed, hooks, also have 4 suckers

1 to 2 proglottids and no uterine pore, only genital pore

Hexacanth eggs

Metacestode type is species dependent

Question 19

Cysticercoid

Answer 19

Single, not invaginated scolex

Invertebrate IH

Question 20

Cysticercus

Answer 20

Single invaginated scolex

Vertebrate IH

Question 21

Coenurus

Answer 21

Many invaginated scolices, vertebrate IH

Question 22

Goal of metacestodes, larvae of cyclophyllideans

Answer 22

Eaten by DH, want IH to die

Question 23

Strobilocercus

Answer 23

Single, non invaginated scolex attached to bladder

Question 24

Hydatid cyst

Answer 24

Brood capsules with 100s of protoscolices

Larvae form for metacestodes

Question 25

Pseudophyllideans

Answer 25

False, scolex is a bothria

1 set of proglottids, and have genital and uterine ores

Eggs are operculated and coracidum

Larvae are metacestodes

Question 26

Pseudophyllidean metacestodes

Answer 26

Procercoid is in the 1st IH and plerocercoid is in the 2nd IH

1st is typically a copecod and 2nd is a fish or frog

Plerocercoid can get very long, sparganum

Question 27

Cestode dx

Answer 27

Fecal float

Pay attention to specific gravity