Cestodes

Question 1

Taxonomy of Cestoda

Answer 1

Question 2

General features of Cestoda

Answer 2

• no sexual dimorphism
• life cycle indirect with one intermediate host, except for Pseudophyllidea order
• adults live in small intestine
• eggs: contain embrionated egg L1 (6-hooked oncosphere) except for D.latum (zygote)
• infection: per os with L2 except for D.latum(L3)
• cestodes: infection caused by adults
• metacestodes:infection caused by larvae in intermediate hosts

Question 3

Morphology of Cestodes

Answer 3

Question 4

Morphology of Cestodes

Answer 4

Question 5

Morphology of Cestodes

Answer 5

Question 6

The only Cestode that develops with 2 intermediate hosts

Answer 6

D.latum

Becomes L1 in the environment, L2 in 1st intermediate host, L3 in 2nd intermediate host (infectious state for final host)

Question 7

The only cestode producing unembridionated eggs

Answer 7

D.latum
Develop in environment to L1

Question 8

L1 — ?
L2 — ?
L3 — ?

Answer 8

L1 = 6-hooked oncosphere
L2 =
L3 = (only in D.latum)

Question 9

Diphyllobothrium latum. Name

Answer 9

Broad tapeworm, fish tapeworm
Mainly fishborn (fresh water) disease of human and animals

Question 10

D.latum. Why is it called broad tapeworm?

Answer 10

Width of the segments are much bigger than height

Very characteristic!

Question 11

D.latum. General characteristic

Question 12

D.latum. Life cycle

Answer 12

Egg ->
coracidium (L1) ->
small copepod crustaceans (Cyclops spp.) where procercoid (L2) develops ->
freshwater fish hets infected by eating crustaceans and plerocercoid (L3) develops

Question 13

D.latum. Prepatent period

Answer 13

2-6 weeks, in dogs 11-15 days

Question 14

D.latum. Pathogenesis, clinical signs

Answer 14

Animals: usually asymptomatic
Man: long-lasting infection (decades), often subclinical or mild (e.g. abdominal discomfort, diarrhea, vomiting), uptake of vitamin B12 may lead to a macrocytic, megaloblastic anaemia in heavily infected individuals

Question 15

D.latum. Diagnosis. Treatment

Answer 15

• FEC with sedimentation method
• examination of proglottids passed in the stool

Treatment: praziquantel

Question 16

Spirometrosis and sparganosis

Answer 16

Caused by plerocercoid of Spirometra spp
The old name of plerocercoid of Spirometra
…..

Question 17

Monieziosis, stilesiosis, thysanosomosis

Answer 17

Tapeworm disease of ruminants
Caused by:
Moniezia expansa (dominant, cosmopolitan) up to 6m, width 15 mm
Moniezia benedeni (less common) up to 4 m, width 25 mm in large animals

Thysaniezia giardi
Avitellina centripuncuta
Stilesia globipuncata

Question 18

Morphology of tapeworms …

Question 19

Life cycle:

Question 20

Tape worms of carnivores

Answer 20

Echinococcus granulosus - dwarf tapeworm of dogs
Echinococcus multilocularis - dwarf tapeworm of foxes
Dipylidium caninum - cucumber-like tapeworm

Taenia pisiformis (0.3-1.5m)
T. hydatigena (0.5-2.5 m)
T. ( syn. Multiceps) multiceps (0.4-1 m)
T. krabbei (syn. T. cervi) (2-2.5 m)
T. ovis (0.5-1.4 m)
T. crassiceps (0.1-0.2 m) foxes
T. taeniaeformis cat tapeworm (0.2-0.6 m) cat, lynx, red foxes
T. serialis (0.2-0.8 m)
Mesocestoides spp. (M. litteratus, M. lineatus) (0.3-2.5 m)

Question 21

What egg type of tapeworms of carnivores is called?

Answer 21

Taenia type egg
- 30-40 micrometers
- oval
- inside 6-hooked oncosphere (L1)

Question 22

Life cycle of tapeworms of carnivores

Answer 22

indirect with 1 intermediate host
Infective stage: L2

Question 23

Echinococcus granulosus

Answer 23

• adult 3-6 mm long
• 3 (2-6) segments
• 4 suckers and rostellum
• lives up to 1 year in anterior half of the small intestine
• taenia-type eggs

Question 24

Echinococcus multilocularis

Answer 24

The dangerous fox tapeworm
Hosts: red foxes, dogs, cats
- adults 2-4 mm long
- 5 segments
- eggs survive 2-3 months in summer, about 8 months in cooler seasons
- 20.000 eggs/segment

Question 25

***Dipylidium caninum***

Answer 25

Flea/double-pore or cucumber seed tapeworm - adult 20-80 cm long - two sets of reproductive organs with bilateral genital pores - in gravies segment 200-300 micrometer sized cocoons of 3-30 eggs

Question 26

***Dipylidium caninum***. Life cycle

Answer 26

- life cycle **indirect** - intermediate hosts — **fleas** - infection with infected intermediate host - PP period: 16-21 days

Question 27

***Dipylidium caninum***. Clinical signs, diagnosis, treatment

Answer 27

Clinical signs are rare Diagnosis: Gracie segment (rice-like) on perinatal skin, fur; PCR Therapy: **praziquantel** (5 ml/bwkg), **epsiprantel (7,5 ml/bwkg)** + flea control

Question 28

Epidemiology.

Question 29

Anoplocephalosis — ?

Answer 29

**Tapeworm disease of horses and donkeys**

Question 30

Anoplocephalosis is caused by ___ ?

Answer 30

***Anoplocephala perfoliata*** ***Anoplocephala magna*** ***Anoplocephala (syn. Paranoplocephala) mamillana***

Question 31

Anoplocephalosis. Location

Answer 31

Specimens of *A.perfoliata* tend to congregate at the **ileocaecal junction**, proximal caecum, ileum, ventral colon

Question 32

Anoplocephalosis. Life cycle

Answer 32

**Indirect** **Cysticercoid (L2)** develop in moss mites (*Oribatidae*) within 2-4 months - PP period: 1-2 months