Cestodes (tapeworms)

Question 1

What are the Cestodes? (6)

Answer 1

• Taenia saginata
• Taenia solium
• Diphyllobothrium latum
• Hymenolepsis nana
• Diphylidium caninum
• Echinococcus spp.

Question 2

Taenia saginata:

-AKA

Answer 2

Beef tapeworm

Question 3

Taenia saginata - Egg:

• size
• shape
• wall
• hooks

*Identical to what?

Answer 3

• 30-40 um
• Spherical
• Thick, radially striated wall
• 3 pairs of hooks

*Identical to T. solium

Question 4

Taenia saginata:

-Scolex morphology

Answer 4

• 4 suckers
• Smooth surface

*Unarmed Rostellum

Question 5

Taenia saginata:

-Proglottid morphology

Answer 5

• Longer than wide

- >13 lateral uterine branches

Question 6

Taenia saginata:

• Geography
• Transmission
• Infection

Answer 6

• South/Central America (NOT in US)
• Beef (cysticerci)
• Small bowel infection by adult worm

Question 7

T/F: T. saginata eggs are not infections.

Answer 7

True

*T. solium eggs are infectious, causes cysticercosis (larval form of disease in humans). Does NOT occur in T. saginata

Question 8

Taenia solium:

-AKA

Answer 8

Pork Tapeworm

Question 9

Taenia solium - Egg:

• size
• shape
• wall
• hooks

*Identical to what?

Answer 9

• 30-40 um
• Spherical
• Thick, radially striated wall
• 3 pairs of hooks

*Identical to T. saginata

Question 10

Taenia solium:

-Scolex morphology

Answer 10

• 4 suckers
• Many tiny hooklets on surface

*Armed rostellum

Question 11

Taenia solium:

-Proglottid morphology

Answer 11

• Longer than wide

- <13 lateral uterine branches

Question 12

Taenia solium:

-Encysted larval form (cysticercosis) consist of..

Answer 12

• 1 cm cyst
• Invaginated scolex w/double row of hooklets*

*Acid-Fast/Birefringent

Question 13

Taenia solium:

-Infections (2)

Answer 13

Intestinal infection
-Pork with cysticerci

Cystercercosis

• Ingestion of eggs shed in feces
• Pork ingestion not required

Question 14

Diphyllobothrium latum:

-AKA

Answer 14

Fish Tapeworm

Question 15

Diphyllobothrium latum - Egg Morphology:

• Size
• Shape
• Features (3)

*Similar to what?

Answer 15

• 60 um
• Oval
• Smooth shell
• Unshouldered Operculum
• Abopercular knob (small)

*Similar to P. westermani, which is larger and has a shouldered operculum

Question 16

Diphyllobothrium latum - Diagnosis:

-Scolex

Answer 16

Resembles elongated Almond w/

-2 longitudinal sucking grooves

Question 17

Diphyllobothrium latum - Diagnosis:

-Proglottid (2)

Answer 17

• Wider than long

- Coiled Uterus in shape of Rosette

Question 18

Diphyllobothrium latum:

-Transmission

Answer 18

Freshwater fish

Question 19

Diphyllobothrium latum - Diagnosis:

• Infection
• Complication

Answer 19

• Intestinal infection

- Vit. B12 deficiency

Question 20

Hymenolepsis nana:

-AKA

Answer 20

Dwarf Tapeworm

Question 21

Hymenolepsis nana - Egg Morphology. (3)

Answer 21

• Thin inner and outer shells
• 2 pairs of polar filaments in space between
• Embryo with hooklets (inner shell)

Question 22

T/F: Hymenolepsis nana is relatively common in the US.

Answer 22

True

Question 23

Hymenolepsis nana:

-Transmission (2)

Answer 23

• Ingestion of beetles

- Person-to-Person may occur

Question 24

Diphylidium caninum:

-AKA

Answer 24

Double Pored Dog Tapeworm

Question 25

Diphylidium caninum:

-Eggs (2)

Answer 25

• Similar to Hymenolepsis diminuta

- Occur in packets of 5-15 eggs

Question 26

Diphylidium caninum:

-Proglottid

Answer 26

Double Genital Pore

-One on each side

Question 27

Diphylidium caninum:

• Infection
• Transmission

Answer 27

Cats and Dogs

-Humans if ingestion of fleas

Question 28

Echinococcus species:

-Cysts (2)

Answer 28

• Protoscoleces

- Hooklets

Question 29

Echinococcus species:

• Transmission
• Definitive host
• Common where?

Answer 29

• Dog shit
• Dog
• Sheep and cattle raising areas (pastoral infection)