Ascarids #4 Flashcards

1
Q

What is the primary host of Heterakis gallinarum?

A

Poultry

Also found in pheasants, water fowl, and raptors

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2
Q

H. gallinarum is a carrier for a protozoan pathogen. Name this protozoan.

A

Histomonas

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3
Q

Identify this egg

A

Heterakis gallinarum

Note the ellipsoid shape, thick, smooth shell, and non-embryonated cell mass. Similar to Ascaridia eggs, but smaller.

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4
Q

Where are the alae located in Heterakis?

A

Caudally

Note that the alae are cranially-located in Toxocara, etc.

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5
Q

List a paratenic host for Heterakis

A

Earthworm

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6
Q

Where does adult Heterakis live in its bird host?

A

Cecum

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7
Q

What is the pre-patent period of Heterakis?

A

1 month

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8
Q

Identify these structures on the caudal end of this adult male Heterakis

A

A) Spicule

B) Cloaca

C) Pre-anal sucker

Note that this species is non-bursate

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9
Q

In which definitive hosts might you find Ascaridia galli?

A

Ducks, geese, chickens, turkeys

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10
Q

Where are the alae found in adult Ascaridia?

A

Caudally

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11
Q

Identify these eggs

A

Eggs Ascaridia galli

Note their barrel shape. Larger in size than Heterakis eggs.

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12
Q

Which organism can serve as a paratenic host for Ascaridia larvae?

A

Earthworm

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13
Q

What is the pre-patent period of Ascaridia galli infections?

A

30-50 days

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14
Q

What are the potential results of heavy Ascaridia galli infections?

A

Fatal intestinal blockage, rupture

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15
Q

Identify the treatment and control measures you might use against Ascaridia galli

A

Drugs:

Ivermectin, levamisole, fenbendazole

Control:

Sanitation to limit the number of eggs in the environment

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16
Q

What kind of life cycle does Anisakis simplex have?

A

Indirect

Note that most ascarids have a direct life cycle. Anisakis is unique in this respect.

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17
Q

What is the definitive host for Anisakis simplex?

A

Marine mammals (dolphins, etc.)

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18
Q

What is the intermediate host of Anisakis simplex?

A

Crustacean

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19
Q

How do humans become infected with Anisakis simplex, and what kind of hosts are humans to this parasite?

A

Eating undercooked fish.

Paratenic host.

20
Q

How does Anisakis simplex cause disease in human hosts?

A

Bowel perforations

Eosinophilic granulomas

Allergic reactions (urticaria, anaphylaxis)

21
Q

What is the name of the horse pinworm?

A

Oxuris equi

22
Q

How many lips do pinworms have?

A

3

Closely related to ascarids

23
Q

What kind of life cycle does Oxyuris equi have?

A

Direct

24
Q

You would normally find adult Oxyuris worms in what age of horses?

A

Weanlings, yearlings, and adolescents.

Uncommon to find adult worms in adult horses.

25
Q

How do Oxyuris equi infections occur in the equine host?

A

Ingestion of a larvated egg.

This usually occurs during grooming activities.

26
Q

Where do adult Oxyuris reside in the equine host?

A

Large intestine

27
Q

True or False:

Male Oxyuris worms possess a caudal bursa

A

FALSE

28
Q

Identify this structure in this adult worm and name the species.

A

Esophageal bulb

Oxyuris equi

(this structure is characteristic for the species)

29
Q

Where do adult female Oxyuris equi lay their eggs?

A

Exit the host via the anus and glue their eggs to the perineal area. The females die after this event.

30
Q

How long does it take the L3 larva of Oxyuris to develop within the egg? (I.e. how long does it take for the egg to become infective?)

A

4-5 days

31
Q

How long is the pre-patent period in Oxyuris equi infections?

A

5 months

32
Q

What is the pathology associated with Oxyuris equi infections?

A

Large numbers of L4 larvae browsing on the gut mucosa can cause inflammation and abdominal discomfort.

Eggs attached to the perineum cause intense anal pruritis

33
Q

How do you detect Oxyuris equi infections?

A

Use cellophane tape to detect eggs around the perineum.

You might be able to find eggs in a fecal float, but this is unlikely (recall that females crawl out of the anus to lay their eggs)

34
Q

Identify this egg

A

Egg of Oxyuris equi

Look for the elongated shape, smooth shell, and flattened edge on one side (lower left in this picture). May or may not have a mucoid plug.

35
Q

Name the species and identify the structures pointed to by the arrows.

A

Oxuris equi

Mucoid plug (top right)

Flattened side (bottom right)

36
Q

Which drugs would you use to treat equine pinworm infections?

A

Macrocyclic lactones, benzimidazoles.

Pyrantel to a lesser extent.

37
Q

How would you treat and control equine pinworm infections?

A

Wash the perineum to remove eggs (this also helps with the intense anal pruritis).

Clean stalls and destroy bedding.

Treat with anthelmentics (macrocyclic lactones and benzimidazoles)

38
Q

Name the mouse pinworm

A

Syphacia obvelata

39
Q

Name the pinworms that can infect rats

A
  • Syphacia muris*
  • Aspicularis* sp.
40
Q

Name the pinworms that can infect hamsters and gerbils

A
  • Syphacia obvelata*
  • Syphacia muris*
  • Aspicularis* sp.
41
Q

What are the potential consequences of heavy rodent pinworm infections?

A

Anal pruritis leading to self-mutilation at tail end

Rectal prolapse

Sticky stools

42
Q

How do you detect rodent pinworm infections?

A

Just like with equine pinworms, use tape to detect eggs in the perianal region.

43
Q

Identify the species

A

Syphacia muris

Note the characteristic banana shape. Just like other pinworms, the egg has a distinct flattened edge.

44
Q

Identify the general class of worms that these eggs come from.

A

Pinworm.

In this case, these are reptile pinworms.

45
Q

What is the name of the human (and other ape) pinworm?

A

Enterobius vermicularis

46
Q

Which of the pinworms are zoonotic?

A

None of ‘em.

Contrary to popular belief, you cannot get pinworms from your dog.

(But maybe tell your kids to wash their hands after scratching their backsides).