03. Cestodes: Order cyclophyllidea, Family Taeniidea ( Genera Taenia, Echinococcus) Flashcards

1
Q

Who is the only definitive host of the beef tapeworm? What is the scientific name of the beef tapeworm?

A

Humans are the only DH

Taenia saginata

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2
Q

Where do the adult tapeworms of Taenia saginata occur in humans?

A

Small intestine

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3
Q

Where do the oncospheres of Taenia saginata hatch from the egg in the host?

A

In the small intestine, it penetrates the intestinal wall and enters the blood stream

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4
Q

How does a human acquire T. saginata? what life cycle stage does it acquire it at?

A

Raw or poorly cooked beef containing: CYSTICERCI

The oncosphere became a cysticerci in the muscle before the animal was killed for eating

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5
Q

What is the process once the cysticercus of Taenia saginata is ingested by the DH/human?

A

Once in the small intestine, the scolex evaginates from the cysticercus and attaches to the wall of the ileum, to begin strobilation

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6
Q

When does the adult Taenia saginata reach maximum maturity and length in the DH?

A

in 3 moths

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7
Q

Can cattle become infected with T. saginata by ingesting the cysticerci?

A

NO

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8
Q

Can humans harbour the metacestodes of T. saginata?

A

NO - the eggs can only hatch in the cow

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9
Q

Are eggs of the family Taeniidae morphologically different?

A

NO - not used for diagnosis

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10
Q

Where does the cysticercus of T. saginata develop?

A

in the muscle of the cow

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11
Q

Does Taenia saginata adult worm have hooks?

A

NO - 4 suckers and lacks hooks

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12
Q

Is the Taenia saginata genital pore common or separate?

A

common

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13
Q

How do we differentiate between T. saginata and T. solium?

A

By looking at the gravid proglottids - T. saginata has ≥15 branches (usually around 20-25)

while T. solium has 14 or less (usually around 14) and they are shorter branches

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14
Q

What is the taxonomy of T. solium?

A

Order Cyclophyllidea
Family Taeniidae
Genera Taenia
Species solium

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15
Q

What is the taxonomy of T. saginata?

A

Order Cyclophyllidea
Family Taeniidae
Genera Taenia
Species saginata

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16
Q

What are the hosts of Pork tapewirm (T. solium)

A

Humans are the only definitive host and pigs are intermediate host - no reservoir hosts for this parasite

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17
Q

Which is more dangerous, T. solium or T. saginata? and why?

A

T. solium, because humans can also be the accidental intermediate host, whereby eggs are ingested and this leads to the disease cysticercosis

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18
Q

How do T. solium and T. saginata eggs compare?

A

They are morphologically indistinguishable - not used for diagnosis

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19
Q

What is found in the eggs of Family Taeniidae?

A
  • Surrounded with a thick radially striated brown embrophore

- Inside is an oncosphere with 6 hooklets

20
Q

Who has hooks between T. saginata and T. solium?

21
Q

What is the morphology of the adult T. solium?

A

Scolex with 4 suckers and 2 circles of hooks

22
Q

What is the condition that arrises if the DH (human) becomes the accidental IH and ingests the eggs of T. solium?

A

Cysticercosis

23
Q

Does cysticercosis only apply to humans?

24
Q

How is the infection passed in T. solium? (pigs)

A

by ingesting eggs or gravid proglottids that originates from the feces of an infected individual

25
Where do the oncospheres hatch out of the egg in T. solium?
The pig ingests embryonated eggs, and in the pig small intestine, the egg hatches to yield the oncosphere and it will enter circulation
26
What is the disease of cycts in the human brain?
Neurocysticercosis
27
What is the clinical diagnosis of T. solium eggs and/or proglottids in human feces?
taeniasis
28
Name some types of cysticercosis infections
occular cysticercosis neurocysticercosis cardio cysticercosis
29
Is treatment of cysticercosis usually effective with anti-parasitic drugs? Of the adult worm?
Treatment suboptimal for cysticercosis Treatment very effective for the adult worm
30
How does Praziquantel work?
Increases the permeability of the worm's membranes toward calcium ions
31
What is the taxonomy of E. granulosus?
Order Cyclophyllidae Family Taeniidae Genera Echinococcus Species granulosus
32
What is the taxonomy of E. miltilocularis?
Order Cyclophyllidae Family Taeniidae Genera Echinococcus Species multilocularis
33
Is Echnococcus big or small relative to other worms?
small (one of the smallest)
34
What is special about Echonococcus spp.?
They only have a scolex, a neck and one of each stage of maturation of proglottid (immature, mature and gravid)
35
What are the DH of Echinococcus?
domestic dogs and other Canidae
36
What are the IH of Echinococcus?
sheep and other hebivores
37
How does Echinococcus effect humans?
They are susceptible to the juvenile stage of the parasite, which may develop into a large, fluid filled cyst (hydatid cyst)
38
What is the disease associated with human exposure to the juvenile stage of Echonococcus?
Hydatid disease (characterized by hydatid cysts)
39
Describe a hydatid cyst
- Instead of having cysticerci, they have hydatid cysts, which contain multiple brood capsules containing the protoscolices. - the cyst is filled with hydatid fluid (HF) and consists of multiple layers
40
What is another name for Hydatid disease?
Echinococcosis
41
T/F E. multilocularis occurs in the Northern hemisphere
true
42
What is caused by Echinococcus granulosus?
cystic echinococcosis
43
What is caused by Echinococcus multilocularis?
alveolar schinococcosis
44
What stage of development of cestodes causes Human echonococcosis?
The larval stages
45
What is the most common form of treatment for Echinococcosis?
Surgery, although it is not always 100% effective + medication postoperatively
46
How does albendazole work?
Albendazole causes degenerative alterations in the tegument and intestinal cells of the worm by binding to tubulin, which inhibits its assembly into microtubules