Blood and Tissue Nematodes Flashcards

1
Q

General characteristics of blood and tissue nematodes

A
  • Not common in U.S.
  • Man is often an accidental or intermediate host
  • Often from eating undercooked beef, fish, pork, etc.
  • Some serologic tests for diagnosis, but lack specificity
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2
Q

Common name for Trichinella spp

A

None

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3
Q

Common name for Dracunculus medinensis

A

Guinea worm

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4
Q

Common name for Baylisascaris procyonis

A

None

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5
Q

Common name for Wuchereria bancrofti

A

None

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6
Q

Common name for Brugia malayi

A

None

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7
Q

Common name for Loa loa

A

African eyeworm

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8
Q

Common name for Onchocerca vulvulus

A

None

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9
Q

Common name for Dirofilaria immitis

A

Dog heartworm

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10
Q

Common name for Pediculus humanus

A

Body louse

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11
Q

Common name for Pediculus capitus

A

Head louse

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12
Q

Common name for phthiris pubis

A

Pubic louse (“crabs”)

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13
Q

Usually caused by ingestion of raw/undercooked pork, bear, and other meat

A

Trichinella spp

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14
Q

Usually caused by ingestion of copepods containing larvae from “step down” wells

A

Dracunculus medinensis

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15
Q

Usually caused by exposure to infected raccoons

A

Baylisascaris procyonis

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16
Q

Usually infected by a mosquito vector (Culex)

A

Wuchereria bancrofti

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17
Q

Usually infected by mosquito vector (Anopheles, Aedes)

A

Brugia malayi

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18
Q

Usually infected by fly vector (Chrysops spp)

A

Loa loa

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19
Q

Usually infected by blackfly or buffalo fly (Simulium)

A

Onchocerca vulvulus

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20
Q

Usually infected by midges (small 2-winged fly) or blackfly

A

Mansonella spp

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21
Q

Usually infected by mosquito vector

A

Dirofilaria immitis

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22
Q

Trichinella spp

  • Diagnostic form
  • Infective form
A
  • Diagnostic: larvae ingested in infected meat

- Infective: encapsulate in striated muscle (active muscles, eye, diaphragm)

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23
Q

Dracunculus medinensis

  • Diagnostic form
  • Infective form
A
  • Diagnostic: copepods containing larvae

- Infective: adults

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24
Q

Wuchereria bancrofti

- Diagnostic and infective form

A

Microfilariae in blood

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25
Q

Brugia malayi

- Diagnostic and infective form

A

Microfilariae in blood

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26
Q

Loa loa

- Diagnostic and infective form

A

Microfilariae in blood

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27
Q

Onchocerca vulvulus

- Diagnostic and infective form

A

Microfilariae in blood

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28
Q

Mansonella spp

- Diagnostic and infective form

A

Microfilariae in blood

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29
Q

Dirofilaria immitis

- Diagnostic and infective form

A

Microfilariae in blood

30
Q

Clinical manifestations of Trichinella spp

A

Triad of symptoms

  • Periorbital edema
  • Muscle pain and tenderness
  • Eosinophlia 20-90%
31
Q

Clinical manifestations of Baylisascaris procyonis

A
  • Rapid neurological deterioration
  • Blood and CSF eosinophilia
  • NOT FOUND IN STOOL
  • Potential biological warfare agent!!!
32
Q

Clinical manifestations of Wuchereria bancrofti

A
  • Chronic infections lead to elephantiasis (obstruction of lymphatics, fibrosis)
  • May also involve kidneys
33
Q

Clinical manifestations of Brugia malayi

A

More distal extremity involvement (below knee, below elbow)

34
Q

Clinical manifestations of Loa loa

A
  • Subcutaneous, painful Calabar swellings (appear and reappear in different areas)
  • Adults can often be seen migrating across surface of eye
  • May have neurologic complications
35
Q

Clinical manifestations of Onchocerca vulvulus

A
  • Adults encapsulated in fibrous tumors in subcutaneous tissues (trunk, extremities, scalp)
  • Wrinkling, thickening of skin (“lizard skin”)
  • Nodules can measure up to 25mm (size of quarter) on most parts of body
  • Blindness occurs when microfilariae collect in cornea or iris
36
Q

Clinical manifestations of Marsonella spp

A
  • Rash
  • Slight fever
  • non-serious infection
37
Q

Clinical manifestations of Dirofilariae immitis

A
  • Adults live in chambers of dog’s heart (infarction)
  • Adults can lodge in pulmonary arteries (coin lesions) but don’t reach maturity in humans
  • No microfilariae in humans
38
Q

Diagnosis of Trichinella spp

A
  • Muscle biopsy (encysted larvae) → squash prep (spiral form), cross-sectioned mounts
39
Q

Diagnosis of Dracunculus medinensis

A

Blister-like papule on arm/leg

40
Q

Diagnosis of Baylisascaris procyonis

A
  • Morphologic identification of larvae in tissue sections in autopsy
  • Radiology (white matter disease)
41
Q

Diagnosis of Wuchereria bancrofiti

A

Depending upon regions of world, infections either nocturnal or subperiodic (day)

42
Q

Diagnosis of Brugia malayi

A

Examine blood at blood at night for microfilariae (thick or thin smear)

43
Q

Diagnosis of Loa loa

A

Examine blood during the day for microfilariae (thick or thin smear)

44
Q

Diagnosis of Onchocerca vulvulus

A

Skin snip → cross section of adult worms and microfilariae

45
Q

Diagnosis of Dirofilaria immitis

A

Examine coin lesion from surgery/biopsy

46
Q

Treatment and preventation of Dracunculus medinensis

A

Treatment
- Winding worm around stick
- Secondary infection is common if breakage of worm occurs
Prevention
- Filtration of water to remove copepods (gauze, t-shirts, filters, etc.)
- Covering water source (from copepods and infected people)

47
Q

These microfilariae are sheathed, no nuclei at tip or cephalic space

A

Wuchereria bancrofti

48
Q
  • These microfilariae are sheathed, space b/w last two nuclei at tip of tail and cephalic space
  • Sheath stains pink on Giemsa stained blood smear
A

Brugia malayi

49
Q

These microfilariae are sheathed, nuclei are continuous to tip of tail

A

Loa loa

50
Q

These microfilariae are non-sheathed and have no nuclei in tip of tail

A

Onchocerca vulvulus

51
Q

These microfilariae have no sheath

A

Mansonella spp

52
Q

Is stool the best specimen choice for identifying blood and tissue nematodes?

A

NO!!!!

53
Q

Largest adult Nematode

A

Dracunculus medinensis

54
Q

Life cycle of Trichinella spp

A

Larvae ingested in infected meat → intestine → mature adults which produce live-born larvae → penetrate intestinal wall → circulate to all areas of the body → encapsulate in striated muscle

55
Q

Life cycle of Dracunculus medinensis

A

Humans ingest copepods containing larvae → larvae released in intestines → larvae burrow through intestinal wall to connective tissue → larvae mature to adult → female migrates to surface of arm/leg to release larvae into water → larvae ingested by copepods

56
Q

Adults living in various lymphatic or other tissues

A

Filariae

57
Q

Microfilariae (larvae) are released in ____

A

Blood

58
Q

Life cycle of Wuchereria bancrofti

A
  • Adults live in lymphatics (esp. lower extremities) → obstruction of lymphatics
  • Female worms release microfilariae into blood that are ingested by mosquito where parasite completes its life cycle
59
Q

Life cycle of Brugia malayi

A
  • Adults live in lymphatics (esp. lower extremities) → obstruction of lymphatics
  • Female worms release microfilariae into blood that are ingested by mosquito where parasite completes its life cycle
60
Q

Life cycle of Loa loa

A

Adults migrate through subcutaneous tissue (calabar swellings and migration across eye)

61
Q

Flattened dorsoventrally

A

Lice

62
Q

This insect has 3 pairs of clawed legs attached to the thorax and large hind legs for jumping, and transmit bacterial infections

A

Fleas

63
Q

This arachnida has a chitenous shield, mouth part attachedt o fused globular body, has no head or attennae, 4 pairs of legs in adults, transmits diseases (RMSF, Lyme, Babesiosis)

A

Ticks

64
Q

This arachnida has no chitenous shield, 8 short legs, burrows into the skin and lays eggs, causes scabies (endemic in U.S.)

A

Mites

65
Q

Types of Arachnida

A
  • Ticks
  • Mites
  • Spiders
  • Scorpions
66
Q

Clinical disease caused by Trichinella spp

A

Trichinosis

67
Q

Clinical disease caused by Wuchereria bancrofti

A

Bancroftian filariasis or elephantiasis

68
Q

Clinical disease caused by Brugia malayi

A

Brugian filariasis or elephantiasis

69
Q

Clinical disease caused by Loa loa

A

Calabar swellings appear and reappear in different areas

70
Q

Clinical disease caused by Onchocerca vulvulus

A

Onchocercosis (“River blindness”)