Parasitology Test 1 Flashcards Preview

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Flashcards in Parasitology Test 1 Deck (126):
1

Definition:

The study of parasites

Parasitology

2

Definition:

  • Lives at the expense of its host
  • gains nourishment from its host
  • lives in/on another organism

Parasite

3

What is symbiosis?

The relationship between 2 different species

4

When one benefits while the other is unaffected it is known as ____________.

Commensalism

5

Both organisms benefit is known as ____________

Mutualism

6

When one organism benefits at the expense of another it is known as ___________

Parasitism

7

What is an ectoparasite?

A parasite that lives on the outside of the host, such as in the hair or on the skin.

Known as an infestation

examples: Scavvies, lice, and mites

8

What is an endoparasite?

A parasite that lives within the body of the host.

Known for infection

9

This type of parasite can live independently of a host, known as the "free-living" stage, and becomes parasitic if ingested or enters through a wound.

Facultative parasite

10

A parasite that is unable to survive outside a host is known as _____________

An obligate parasite

11

What is a pseudoparasite?

An artifact mistaken for a parasite

ex. pollen or hair

12

What is a definitive host?

Harbors the adult and/or sexual stage

AKA final host

13

What is an intermediate host?

Harbors the larval or asexual stage of a parasite

14

What is an accidental/incidental host?

A parasite establishes itself in a host other than its natural host.

Normally the parasite lives in or on host other than humans

AKA "dead-end" host is no longer transmitted

15

Definition:

This is a living carrier that transmits a parasite

-arthropods

Vector

16

What is a reservoir?

A continuous source of infection

-An animal or area that harbors the infective parasite

17

An infected individual showing no signs of clinical manifestation but has the potential to infect others is known as being a ___________

Carrier

18

What is the greatest vehicle for most of transmission of parasites?

Food

19

Parasitic life cycle:

During this stage the parasite is capable of invading a definitive host

Infective stage

20

Parasitic life cycles:

During this stage a parasite can be identified by examining appropriate specimen from an infected host

Diagnostic stage

21

What is the difference between parasitic infection and parasitic disease?

Parasitic infection: infected host suffers very little damage and typically has no symptoms

Parasitic disease: host suffers pathologic changes and has various symptoms

22

What are some common symptoms of parasites? (9)

  • Diarrhea
  • fever
  • chills
  • abdominal pain and cramping
  • anemia
  • bowel obstruction
  • enlarged organs
  • skin lesions
  • flatulence

23

What is the pathogenesis of a parasite dependent on?

  • Number of parasites
  • Size of parasite
  • Tissue tropism
  • Specific mechanisms of tissue damage
  • Location and migration patterns
  • Patients immune system

24

What is a mechanical effect due to a parasite?

Obstruction of vessels or hollow viscera

25

True or False:

Parasites can invade or destroy host cells

True

26

True or False:

Parasites can cause an inflammatory reaction on their own or due to their byproducts

True

27

True or False:

Parasites compete for nutrient but do not cause vitamin deficiency

False- Parasites can cause vitamin deficiency which can in turn cause anemia

28

What is a physical barrier against parasites?

Intact skin

29

What is a chemical barrier against parasites?

Proper hand washing

30

What is natural resistance to parasite?

Genetic factors that may influence resistance

31

Immunologic Responses:

When a parasite is antigenic, what type of antibodies are typically produced against it?

IgM and IgE

32

What are some recent advances in chemotherapy? (2)

  • Less toxic to host
  • lessens need for surgical intervention

33

What does fresh blood in stool indicate?

  • acute lower GI bleeding

34

When should Feces be sieved?

  • after drug therapy for tapeworms

35

Iodine wet mount characteristics 

  • eggs and cyst structure clearer
  • kills and distorts trophozoites
  • motility cannot be observed

36

Formalin-Ethyl Acetate Technique characteristics

  • Use solutions w/ lower specific gravity
  • Concentrates organisms in sediment
  • Recommended for general diagnostic labs

37

What is Cellophane Tape Prep used to recover?

  • Recover Enterobius vermicularis eggs

38

What does the Enterotest recover?

  • Retrieves duodenal material
  • Recovery
  • Giardia lamblia
  • Isospora belli
  • Strongyloides stercoralis
  • Fasciola hepatica
  • Clonorchis sinensis

39

Blood Examination is used to look for?

Recovery and identification

  •  Malaria
  •  Trypanosomes
  •  Microfilariae
  •  Babesia
  •  Leishmania

40

Initial examination guidelines:

Within what time should the following be examined:

  • liquid
  • semi-solid
  • formed

Possible answers:

  • within 1 hour
  • within 30 minutes
  • within 24 hours (May refrigerate up to 48 hours)

  • Liquid
    • within 30 minutes
  • Semi-solid
    • within 1 hour
  • Formed
    • within 24 hours (may refrigerate up to 48 hours)

41

True or False:

Polyvinyl alcohol is used to preserve eggs, cysts, and larvae

False:

Polyvinyl alcohol is used to preserve cysts and trophozoites

42

True or False:

10% Formalin is used to preserve cysts and trophozoites

False: 10% Formalin is used to preserve eggs, cysts, and larvae

43

What are 3 stool specimen preservatives?

  1. Merthiolate-Iodine-Formaldehyde (MIF)
  2. Sodium Acetate-Acetic Acid-Formalin (SAF)
  3. Schaudinn's Fixative

44

In a thin prepared blood smear, how many fields must be viewed at 100x for species identification?

200-300 fields

45

When malaria is suspected, what type of blood sample collection method is preferred?

capillary blood because anticoagulants distort the morphology

46

What types of tests are used for antigen detection of parasites? (3)

  • Indirect immunofluorescent (IIF)
  • Enzyme immunoassay (EIA)
  • Enzyme-linked immunosorbent assay (ELISA)

47

What types of tests are used for antibody detection of parasites? (3)

  • Immunosorbent antibody tests
  • complement fixation
  • ELISA

48

What phylum do amoebae belong to?

Sarcomastigophora

49

What class do amoebae belong to?

Lobosea- move by use of pseudopodia

50

How do trophozoites multiply?

Binary fission

51

Which is the motile, feeding, reproducing stage of an amoeba?

-Troph

-Cyst

Trophs

52

Which is the infective stage?

-Trophs

-Cysts

Cysts

53

True or False:

Trophs are transmitted to humans

False:

Trophs are not transmitted to humans due to susceptibility to environment

54

Where to trophs live?

In the large intestines

55

How are cysts passed?

In feces

56

How do humans become infected with amoebae?

By ingesting cysts due to food/water contamination

57

Where are trophs primarily recovered from?

soft, liquid or loose stool

58

Cysts are typically found in ________ ________

Formed stool

59

This amoeba is the most pathogenic

Entamoeba histolytica

60

How are Entamoeba histolytica transmitted?

Transmitted via:

  • ingestin of cysts in food/water
  • unprotected sex,
  • contaminated water,
  • and flies/roaches that carry it to unprotected food

61

Name this amoeba:

Nucleus

  • central karysome
  • even pattern of peripheral chromatic
  • spoke-like pattern around karyosome

Trophozoite may contain ingested RBCs

Cysts have rounded chromatoid bodies

Entamoeba histolytica

62

Name this amoeba:

Nucleus

  • central karysome
  • even pattern of peripheral chromatic
  • spoke-like pattern around karyosome

Trophozoite may contain ingested RBCs

Cysts have rounded chromatoid bodies

Entamoeba histolytica

63

Name this amoeba:

Nucleus

  • central karysome
  • even pattern of peripheral chromatic
  • spoke-like pattern around karyosome

Trophozoite may contain ingested RBCs

Cysts have rounded chromatoid bodies

Entamoeba histolytica

64

Name this amoeba:

Nucleus

  • central karysome
  • even pattern of peripheral chromatic
  • spoke-like pattern around karyosome

Trophozoite may contain ingested RBCs

Cysts have rounded chromatoid bodies

Entamoeba histolytica

65

This amoeba is morphologically identical to E. histolytica with the expection of no RBCs in the troph and it is nonpathogenic

Entamoeba dispar

66

Name the amoeba:

  • Commensal
  • "small-race Entamoeba histolytica"
    • morphologically similar
    • diameter less than 10 um
  • Nonpathogenic

Entamoeba harmanni

67

Name this amoeba:

  • Troph is 5-10 micrometers
    • finger shaped pseudopods with nonprogressive movement
    • 1 nuclei
    • peripheral chromatin is beaded
    • karyosome is centrally or eccentrically located

Entamoeba hartmanni

68

Name this amoeba:

  • Troph is 5-10 micrometers
    • finger shaped pseudopods with nonprogressive movement
    • 1 nuclei
    • peripheral chromatin is beaded
    • karyosome is centrally or eccentrically located

Entamoeba hartmanni

69

Name this amoeba:

  • Cysts are 5-10 micrometers
    • 1-4 nuclei
    • cytoplasm is finely granular

Entamoeba hartmanni

70

Name this amoeba:

  • Cysts are 5-10 micrometers
    • 1-4 nuclei
    • cytoplasm is finely granular

Entamoeba hartmanni

71

This amoeba:

  • must be differentiated from E. histolytica,
  • it is commensal,
  • has a large eccentric karyosome, and
  • irregular clumped peripheral chromatin

Entamoeba coli

72

Entamoeba histolytica characteristics

Most pathogenic

›Destroys lining of the intestines

›Infection found in 10% of world population

›presence of ingested RBCs is diagnostic**

 

73

Name the amoeba:

  • Must be differentiated from E. histolytica
  • Troph is 15-50 micrometers
    • may include ingested bacteria

Entamoeba coli

74

Name the amoeba:

  • Must be differentiated from E. histolytica
  • Nucleus
    • large, eccentric karyosome
    • irregular, clumped peripheral chromatin
  • Cyst
    • 10-35 micrometers
    • 1-8 nuclei
    • splinter-shaped chromatoid bodies

Entamoeba coli

75

Name the amoeba:

  • Must be differentiated from E. histolytica
  • Nucleus
    • large, eccentric karyosome
    • irregular, clumped peripheral chromatin
  • Cyst
    • 10-35 micrometers
    • 1-8 nuclei
    • splinter-shaped chromatoid bodies

Entamoeba coli

76

Name the amoeba:

  • Must be differentiated from E. histolytica
  • Troph is 15-50 micrometers
    • may include ingested bacteria

Entamoeba coli

77

  • This is the only amoeba to ingest WBCs
  • Has no known cyst stage
  • Trophs are 8-20 micrometers
    • active motility with multiple pseudopods
    • 1 nuclei with central karyosome
    • peripheral chromatin
    • achromatic granules arranged in strands
    • many vacuoles
  • Found in mouth between teeth

 

Entamoeba gingivalis

78

Name the parasite:

  • Commensal
  • nucleus
    • large, blot-like karyosome
    • lacks peripheral chromatin
  • vary small
  • Trophs are 6-12 micrometers
    • large irregular "blot like" karyosome
    • absence of peripheral chromatin

Endolimax nana

79

Name the parasite:

  • Commensal
  • nucleus
    • large, blot-like karyosome
    • lacks peripheral chromatin
    • vary small
  • Trophs are 6-12 micrometers
    • large irregular "blot like" karyosome
    • absence of peripheral chromatin

Endolimax nana

80

Name the parasite:

  • Commensal
  • nucleus
    • large, blot-like karyosome
    • lacks peripheral chromatin
    • vary small
  • Cysts are 7-10 micrometers
    • spherical, ovoid or elliptical
    • 4 nuclei is most common form
    • no peripheral chromatin
    • no chromatoid bars

Endolimax nana

81

Name the parasite:

  • Commensal
  • nucleus
    • large, blot-like karyosome
    • lacks peripheral chromatin
    • vary small
  • Cysts are 7-10 micrometers
    • spherical, ovoid or elliptical
    • 4 nuclei is most common form
    • no peripheral chromatin
    • no chromatoid bars

Endolimax nana

82

This parasite is:

  • Found in pigs and humans
  • Nucleus
    • large, irregular shape
    • lacks peripheral chromatin
  • Trophs are 8-12 micrometers
    • progressive sluggish movement
    • 1 nucleiwith central karyosome
    • no peripheral chromatin

Iodamoeba butschlii

83

This parasite is:

  • Found in pigs and humans
  • Nucleus
    • large, irregular shape
    • lacks peripheral chromatin
  • Cysts are 8-10 micrometers
    • large glycogen mass with definite borders
      • looks like a vacuole

Iodamoeba butschlii

84

This parasite is:

  • Found in pigs and humans
  • Nucleus
    • large, irregular shape
    • lacks peripheral chromatin
  • Cysts are 8-10 micrometers
    • large glycogen mass with definite borders
      • looks like a vacuole

Iodamoeba butschlii

85

This parasite is:

  • Found in pigs and humans
  • Nucleus
    • large, irregular shape
    • lacks peripheral chromatin
  • Cysts are 8-10 micrometers
    • large glycogen mass with definite borders
      • looks like a vacuole

Iodamoeba butschlii

86

This parasite:

  • is an ameboflagellate
    • opportunistic parasite
  • free-living stage found in water, soil, and decaying vegetation
    • warm water lakes
    • humans = accidental host
    • enters through nasal mucosa

Naegleria fowleri

87

This parasite causes primary amoebic meningoencephalitis

  • headache
  • fever
  • vomiting
  • coma
  • death within 6 days

Naegleria fowleri

88

How is lab ID done or Naegleria fowleri?

microscopic examination of CSF

but, tissue of nasal discharge may also be used

89

This species causes keratitis and Granulomatous amoebic encephalitis (GAE) which is chronic and has symptoms of seizure, stiff neck, and vomiting. GAE is untreatable.

Acathomoeba species

90

  • This species is found in water, soil, and decayin vegetation in the free-living stage
  • It is an opportunistic parasite
  • Enters through nasal mucosa or skin
  • Patient is usually immunocompromised
  • Poor contact lens care can cause infection

Acanthomoeba species

91

What specimens are used to ID Acanthomoeba species?

CSF

Brain tissue

Corneal scrapings

92

  • Trophs:
    • 12-45 micrometers
    • sluggish movement, spine-like pseudopods (similar to N. fowleri)
    • 1 nuclei with large karyosome
    • no peripheral chromatin
  • Cysts:
    • 8-25 micrometers
    • double wall:
      • inner- smooth
      • outer- jagged
    • nucleus
      • large karyosome
      • lacks peripheral chromatin

Acanthomoeba species

93

This parasite must be considered pathogenic when found in large numbers in patients with abdominal symptoms who have no other apparent etiologic agent.

Blastocystis hominis

94

Cyst:

  • 6-40 micrometers
  • homogeneous-staining central body
    • occupies about 70% of cell
  • nuclear material between central body and outer membrane
  • considered pathogenic when found in large numbers with abdominal symptoms and no other apparent etiologic agent

Blastocystis hominis

95

  • Only ciliate known to be a human pathogen
  • hogs are the true host; humans serve as an accidental host
  • Most infections are asymptomatic but may cause self-limiting diarrhea
  • Huge
  • Pathogenic
  • Fecal-oral route

Balantidium coli

96

What phylum and class are flagellates?

Phylum: sarcomastigophora

Class: Zoomastifophorea

97

  • Most common parasite in the US
  • worldwide health problem
  • traveler's diarrhea
  • Wild animals are the definitive host
  • Beavers are a reservoir host
  • Fecal-oral route
  • ingestion of cysts through contaminated water
  • trophs multiply by binary fission
  • cysts are resistant to chlorination

Giardia Lamblia

98

What tests are capable of diagnosing Giardia lamblia?

 

Enterotest, ELISA, and EIA

99

Trophozoite:

  • 12-15 micrometers long
  • 5-15 micrometers wide
  • bilaterally symmetrical
  • sucking disks on ventral side
  • 2 nuclei
  • 4 lateral flagella; 2 ventral flagella
    • "falling leave" motility

Giardia lamblia

100

Cyst:

9-12 micrometers

4 nuclei clustered at one end

4 parabasal bodies (rod like structures)

Giardia lamblia

101

  • Commensal
  • Troph:
    • 6-20 micrometers long; 5-7 micrometers wide
    • single, large anterior nucleus
    • round anterior end
    • curved posterior
    • cytostomal grove
    • 4 anterior flagella

Chilomastix mesnili

102

Cyst:

  • 6-10 micrometers long; 4-6 micrometers wide
  • lemon shaped with clear anterior knob
  • single nucleus
    • difficult to see
  • curved cytosome
    • appearing as "shepherd's crook"

Chilomastix mesnili

103

Lemon shaped cyst with clear anterior knob... what parasite is this?

Chilomastix mesnili

104

  • One of the smallest parasites
    • difficult to detect
  • lives in large intestines of humans
    • controversy over pathogenecity
    • exact mode of transmission is unknown
  • Patients are often asymptomatic
    • if symptomatic
      • diarrhea and abdominal pain

Dientamoeba fragilis

105

  • One of the smallest parasites
    • difficult to detect
  • lives in large intestines of humans
    • controversy over pathogenecity
    • exact mode of transmission is unknown
  • Patients are often asymptomatic
    • if symptomatic
      • diarrhea and abdominal pain
  • Nucleus:
    • 2 nuclei
      • about 20% have 1 nucleus
      • delicate nuclear membrane
      • karyosome composed of 4-8 chromatin dots
  • Trophs:
    • 5-8 micrometers; asymmetric
    • considerable variation seen
  • No known cyst stage

Dientamoeba fragilis

106

  • Nonpathogenic- found in stool
  • Troph:
    • 7-15 micrometers long; 7-14 micrometers wide
    • tear-drop shaped
    • anterior nucleus
      • central, small karyosome
    • 4 anterior flagella; 1 trailing flagellum
    • undulating membrane
      • extends the entire length of body

Trichomonas hominis

107

  • Sexually-transmitted
    • "Trichomoniasis"
    • urethritis (men)
    • vaginitis
  • Troph:
    • similiar to T. hominis
    • undulating membrane
      • extends half the length of body

 

Trichomonas vaginalis

108

This species causes Leishmaniasis

Leishmania species

109

This species causes African Sleeping Sickness

Trypanosoma species

110

What are the characteristics of an amastigote?

oval

non-flagellated

found in human tissue, muscle, and CNS macrophages

111

What species is this:

Leishmania species

112

This morphologic form is not encountered in humans and is long and slender with flagellum

promastigote

113

This morphologic form is spindle-shaped with flagellum and has an undulating membrane (1/2 body)

Epimastigote

114

This morphologic form is more frequently in humans, is long and slender to short and has a full length undulating membrane. It may appear to look like a "C" or "U" shape in blood smears.

Trypomastigote

115

What is the vector for Leishmania species?

Sandfly

116

What are the 4 pathogenic species or Leishmania?

  • L. braziliensis
  • L. donovani
  • L. tropica
  • L. mexicana

117

  • Mucocutaneous leishmaniasis
    • AKA "New World" leishmaniasis
    • "Uta" or "Espundia"
  • Central and South America
    • especially Brazil

 

L. braziliensis

118

  • Visceral leishmaniasis
    • AKA "Kala-azar" or "Dumdum fever"
  • geographical locations:
    • Middle East; north and east Africa
    • Asia
    • Mediterranean
    • South America
  • Lesion at inital site
  • fever, chills, sweating, weightloss, splenomegaly, hepatomegaly
  • Death can ocur without treatment after about 2 years
  • Amastigotes in lymph nodes

L. donovani complex

119

  • Mostly cutaneous lesions
  • AKA:
    • Old World leishmaniasis
    • Oriental boil
    • Baghdad or Delhi boil
  • Geographical locations:
    • Mediterranean (Iraq, Iran, Afghanistan)
    • Asia, Africa, Central America

L. tropica complex

120

How is Trypanosoma brucei transmitted?

By the Tsetse fly

121

What causes East African Sleeping Sickness?

T. brucei rhodesiense

122

What causes West African Sleeping Sickness?

T. brucei gambiense

123

What causes Chagas' disease?

T. cruzi

124

This parasite is transmitted via the Tsetse fly

Trypanosoma brucei

125

  • South and Central America
    • especially Brazil
  • South American sleeping sickness
    • AKA Chagas' Disease
  • Transmitted via the reduviid bug
    • AKA kissing bug or conenose bug
    • posterior station transmission
  • Can affect: GI tract, colon, and esophageal areas
  • May cause enlarged heart
  • Can result in death if left untreated

Trypanosoma cruzi

126

What is the vector for T. cruzi?

The Reduviid bug

AKA kissing bug or conenose bug