04. Cestodes: Order cyclophyllidea, Family Hymenolepididae Flashcards

1
Q

What is the taxonomy of H. nana?

A

Order Cyclophyllidea
FAmily Hymenlopididae
Genus Hymenolepis
Species nana

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2
Q

What is the taxonomy of H. diminuta?

A

Order Cyclophyllidea
FAmily Hymenlopididae
Genus Hymenolepis
Species diminiuta

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3
Q

What is the common name of H. nana?

A

dwarf tapeworm

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4
Q

What is the common name of H. diminuta?

A

rat tapeworm

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5
Q

What are the characters of Family Hymenolepididae?

A
  • Proglottids that are wider than they are long
  • mature proglottids contain a small number of eggs
  • gravid proglottids disintegrate in host and release eggs
  • 3-4 testes
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6
Q

What is the IH of Hymenolepididae family?

A

an invertibrate is the IH

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7
Q

What are the two species in Family Hymenolepididae that infect humans?

A

H. nana and H. diminuta

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8
Q

Who is the most common culprit of H. nana?

A

Children, because they play in dirt and often eat it

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9
Q

Who is a reservoir host for H. nana?

A

rodents

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10
Q

What is special about H. nana?

A

They are the only tapeworm that does not need an IH to complete its life cycle

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11
Q

What is the length of H. nana?

A
  • 1.5-4.5 cm in length

- adult has 150-200 prglottids

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12
Q

How many suckers and hooks in H. nana?

A
  • four suckers

- 1 row of hooks

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13
Q

Who is most affected by H. diminuta?

A

Children, because they play in dirt and often eat it

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14
Q

What is the length of H. diminuta?

A

20-40 cm in length

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15
Q

How many suckers and hooks in H. diminuta?

A
  • 4 suckers

- NO hooks

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16
Q

What are possible reservoir host of H. diminuta?

A
  • dogs
  • cats
  • many rodent species
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17
Q

What is the taxonomy of D. caninum?

A

Order Cyclophyllidea
Family Dipylidiidae
Genus Dipylidium
Species Caninum

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18
Q

What is the common name for Dipylidium caninum?

A

Double-pored dog tapeworm

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19
Q

Who is the major DH of Dipylidium caninum?

A

Canine

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20
Q

What makes them a “double pored” worm?

A

the adult worms have genital pores on either side

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21
Q

What is different about the uterus of D. caninum?

A
  • it breaks down into egg capsules, each containing -

several eggs with oncospheres

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22
Q

How are proglottids/eggs spread?

A
  • it is the gravid proglottids that are passed in feces and the eggs are released in capsules
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23
Q

How many suckers and hooks in D. caninum?

A
  • four suckers

- four rows of hooks

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24
Q

What is the taxonomy os S. mansonoides?

A
Order Pseudophyllidean 
Genus Spirometra (previously Diphyllobothrium)
Species mansonoides
25
Q

What is special about D. latum and S. mansonoides worms?

A

they contain some of the largest tapeworms known, with lengths of around 10 m

26
Q

What are the characteristics of the order Pseudophyllidean?

A
  • scolex contains 2 grooves (aka bothria)
  • male and female genital openings are separated, and located mid-ventrally in the mature proglottid
  • proglottids are not shed, rather shed eggs directly into the gut via a uterine pore
27
Q

What are bothria? what is their functions

A
  • slit-like organs for adhering to the intestine of the host

- they pinch the intestinal wall of the host to hold the worm in place

28
Q

Why is the life cycle of order pseudophyllidean complex?

A

because there are 3 or more hosts

29
Q

What are the hosts of order pseudophyllidean?

A

first intermediate host: copepod
second intermediate host: fish/amphibian
DH: fish-eating mammal

30
Q

What are examples of fish that can be the second intermediate hosts of worms of the order pseudophyllidean?

A

Minnow, northern pike, perch, salmon, trout

31
Q

Where are human infections common of worms of the order pseudophyllidean?

A

the Great Lakes region of North America and in Northern Europe, particularly in Finland (many freshwater lakes, and common practice to eat pickled fish; doesn’t kill the parasites)

32
Q

What is the common name of Diphyllobothrium latum?

A

Broad fish tapeworm

  • Broad - proglottids
  • fish - DH is infected by eating fish
33
Q

What are common DH of D. latum?

A

Bears, dogs, cats, foxes, mink, racoons, walruses, seals and humans

34
Q

What does D. latum have a unique affinity for? Why is this important clinically?

A

Vitamin B12, because it will affect the cellular metabolism in the infected host

35
Q

Why are bears a common DH of D. latum?

A

They eat fish

36
Q

Why is D. latum found in cats and dogs?

A

they may eat uncooked scraps of fish

37
Q

Humans can also become infected with D. latum. How?

A

by eating raw or undercooked fish

38
Q

What is the morphology of D. latum eggs?

A
  • The are oval of ellisoidal
  • Range in size from 55-75 µm by 40-50µm
  • operculum (can be difficult to see)
  • small knob at the other end
39
Q

What is different about the eggs passed in stool of D. latum?

A

They are unembryonated, become embryonated in water

40
Q

What is the morphology of the adult D. latum?

A
  • scolex has 2 slit-like grooves (bothria)
  • proglottids are wider than they are long
  • genital pores are mid-ventral
  • longest tapeworm in humans averaging 10m
41
Q

What is the disease caused by Spirometra mansonoides?

A

Sparganosis

42
Q

What are some DH of S. mansonoides?

A

dogs, cats, birds, and wild carnivores, humans are accidental hosts

43
Q

What is the first IH of S. mansonoides?

A

Copepods and other freshwater crustaceans

44
Q

What are the second IH hosts of S. mansonoides?

A

birds, reptiles, and amphibians

45
Q

Where are the most common cases of sparginosis in non-human animals?

A

North america

46
Q

What is the life cycle of order cyclophyllidea (summary)

A

Basic life cycle, usually 2 hosts; H. nana does not require 2 due to autoinfection

47
Q

What is the life cycle for cestodes using a vertibrate as an IH? (summary)

A

Embryonated egg (with oncospere) –> cysticercus (IH) –> adult tapeworm (DH)

48
Q

What is the life cycle for cestodes using an invertibrate as an IH? (summary)

A

Embryonated egg (with oncospere) –> cysticercoid larvae (IH) –> adult tapeworm (DH)

49
Q

What is the life cycle of order pseudophyllidean? (summary)

A
  • 3-4 hosts
  • Unembryonated egg (with developing oncosphere) –> coracidium (free-living in water) –> plercercoid larvae (1st IH) –> plerocercoid (2nd IH) –> adult tapeworm (DH)
50
Q

What stage is usually killed most effectively by anthelminthic drugs?

A

The adult stage + the eggs inside it

51
Q

What is the possible mode-of-action of Praziquantel?

A

Thought to increase membrane permeability to calcium ions - indices contraction of the parasite, resulting in paralysis

52
Q

Are tapeworms visible once the host is treated by Praziquantel?

A

No, the worms are digested. Parts of the worm can be found in feces

53
Q

What else is Niclosamide used to control?

A

snail populations in schistosomiasis control campaigns

54
Q

What life stage is susceptible to Nicloamide?

A

adult forms, not juvenile forms

55
Q

What is the possible mechanism of action of Niclosamide?

A

Thought to possible block ATP production by uncoupling oxidative phosphorylation in the tapeworm

56
Q

What is Albendazole used for?

A

it is a broad spectrum anthelminthic, effective against cestodes, trematodes and nematodes

57
Q

Where was Albendazole developped? When?

A

SmithKline Animal Health Laboratories in 1972

58
Q

What category of drugs is Albendazole?

A

Benzimidazole

59
Q

How do benzamidazoles work?

A

Bind to β-tubulin, preventint its polymerization with α-tubulin to form microtubules