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Parasitology Lec > Protozoan > Flashcards

Protozoan Flashcards

1
Q

Usual mode of transmission parasite

A

Ingestion

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2
Q

Most members of the ameba inhabit which part/ organ

of the body?

A

Large intestine

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3
Q

The small intestine is the site of

A

Encystation and

Excystation

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4
Q

True or False: Lectin is used by pathogenic amebae to attach itself on the intestinal mucosa

A

True.

● by Entamoeba histolytica

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5
Q

True or False: The cyst is the infective stage in the life cycles of all members of the amebae

A

False
● E. gingivalis is diagnosed through oral scraping -
trophozoite

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6
Q

Which commensal amebae is known for its capacity to ingest leukocytes? Give the complete scientific name.

A

Entamoeba gingivalis

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7
Q

Which amebae is known for causing PAM? Give the complete scientific name

A

Naegleria Fowleri: Free living amebae

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8
Q

Locomotor apparatus of amebae

A

pseudopod. ○ “False feet”

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9
Q

Amoeba have cytoplasm - Ectoplasmic extension wherein

where pseudopods are found,

A

outer ectoplasm

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10
Q

one that would lead to infection.

Characterized by the most number of nuclei

A

Mature cyst

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11
Q

True or false: Trophozoites are usually mononucleated.

A

True

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12
Q

a reaction of the body to the agent.

A

Mucus

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13
Q

True or false Red cells are indicative of
ulceration in the sample

It is also indicative that the parasite is
invasive.

A

True

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14
Q

The enzyme that allows it to ulcerate

the intestine.

A

Cysteine proteinase

E. histolytica initiates response by increasing the mucous
production which ulcerates the intestinal mucosa through
its enzyme cysteine proteinase

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15
Q

food of trophozoites. The moment you see one,

ulceration occurred already

A

RBCs

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16
Q

trophozoites with ingested

RBCs. Very distinct in Entamoeba.

A

Hematophagous trophozoites -

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17
Q

Ameba Generalized characteristic

A

Habitat: True with all the amoebae, they inhabit the Colon or large intestine

Infective Stage: True with all the amoebae, infective stage is cyst (only those that are encysting)
a. Except: E. gingivalis

Pathogenicity: Commensals (nonpathogenic)
a. Except: E. histolytica (causes amoebic
dysentery and ALA or amebic liver abscess
b. Free living amoebae are also non-
pathogenic
i. PAM: Naegleria fowleri
ii. GAM: Acanthamoeba

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18
Q

maturity is determined whether

A

whether or
not cyst has attained max. number of nuclei, which
depends on the spp.

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19
Q

One mature cyst can produce as many trophozoites as

A

the

number of nuclei it possesses (in mature stage)

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20
Q

What are the INTESTINAL AMEBAE

A 
E. histolytica (Pathogenic)
E. dispar
E. moshkovski
E. harmanni
Endolimax nana
Iadoliman nana
Iodamoabe butschlii
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21
Q

3 Different types of Amoeba

A

Entamoeba
Endolimax
Iodamoeba

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22
Q

Most invasive of the Entamoeba parasites

● Only member to cause colitis and liver abscess

A

ENTAMOEBA HISTOLYTICA

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23
Q

Means of attachment of ENTAMOEBA HISTOLYTICA

A

Lectin

When it attaches, it creates a pore (amoebapore) para mabutas

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24
Q

Multiplication means of ENTAMOEBA HISTOLYTICA

A

nuclear and cytoplasmic

divisions (binary fission)

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25
Q

Characteristics of Entamoeba Histolytica Trophozoite

A

Centrally located karyosome

Evenly distributed peripheral chromatin

Unidirectional (progressive) Pseudopod (fingerlike projection) motility
Extruded to one direction

Cystic wall is thin

Cytoplasm is clean looking

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26
Q

Characteristics of Entamoeba Histolytica Cyst

A

Spherical in shape

Centrally located karyosome

Evenly distributed peripheral chromatin

Chromatoidal bars or bodies are cigar-shaped

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27
Q

Other modes of transmission:

A

Venereal transmission through fecal-oral contact.

Direct colonic inoculation through contaminated
enema equipment.

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28
Q

A pseudopod-forming non-flagellated protozoan parasite.

A

Entamoeba Histolytica

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29
Q

The life cycle consists of two stages:
○ An infective cyst
○ An invasive trophozoite form

A

Entamoeba Histolytica

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30
Q

The quadrinucleate cyst is resistant to gastric acidity and

desiccation, and can survive in a moist environment for several weeks

A

TRUE E. histolytica

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31
Q

Mechanism for virulence of E. histolytica

A

Contact-dependent cell killing
Cytophagocytosis - cell eater (consumes RBCs)

➢Lectin : Enzyme for the attachment of parasite to host
➢ Ameba pores : Formation of holes
➢ Cysteine Proteinase : Enzyme for tissue
destruction and spreading of infection

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32
Q

Contact-dependent cell killing

A

E. histolytica

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33
Q

E. histolytica cases may exist as Asymptomatic

A

Majority of cases present as asymptomatic infections with cysts being passed out in the stools (cyst carrier state).

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34
Q

Manifestations of E. histolytica infection:

A
  1. Asymptomatic
  2. Amebic Colitis
  3. Ameboma
  4. Amebic Liver Abscess
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35
Q

Manifestations of E. histolytica infection:

Most common presentation. It is the
inflammation of the large colon.

associated with a lot of bleeding and mucus

type of diarrhea here is watery and explosive = Amebic dysentery

Abdominal pain, blood and mucus in stool

A

Amebic Colitis

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36
Q

TRUE OR FALSE
Manifestations of E. histolytica infection:

Fever is not common and it occurs only in one third of patients.

A

TRUE

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37
Q

Manifestations of E. histolytica infection:

Children may develop

A

fulminant colitis

Severe bloody diarrhea, fever, abdominal
pain

38
Q

Serious consequences of perforation (or ulceration) causes

A

Secondary bacterial peritonitis

39
Q

When the amoeba invades the adjacent
intestinal organs, just like the liver, lungs, or any part of the peritoneal cavity. They may form cystic mass.

Mass-like lesion with abdominal pain and history of dysentery

Can be mistaken as a carcinoma (tumor/cancer)

May be asymptomatic

Occurs in less than 1% of intestinal
infections

A

Ameboma

40
Q

The most common organ that is invaded

The abscess appearance of this amoebic is very characteristic. It’s characterized by anchovy-sauce just like in sardines (tomato).

A

Amebic Liver Abscess

41
Q

Most common extraintestinal form of amebiasis

A

Amebic Liver Abscess

42
Q

Usually presents with fever and RU quadrant pain. (Book) Several studies have shown these two as the most frequent complaints, particularly in acute cases (<2 weeks duration). Hepatomegaly is present in 50% of cases.

A

Amebic Liver Abscess

43
Q

DIAGNOSIS OF E. HISTOLYTICA:
The standard method of parasitological diagnosis is microscopic detection of the trophozoites and cysts in stool specimens. Ideally, a minimum of ____ stool specimens collected on different days should be examined.

A

3

44
Q

diagnosis of E. histolytica

A

DFS

Concentration technique (FECT - Formalin Ether/Ethyl Acetate Concentration
Test and Merthiolate Iodine Formalin Concentration Test (MIFC))

PCR (Polymerase Chain Reaction)

Serological tests (ELISA): Enzyme-linked immunosorbent assay

Ultrasound, CT scan, MRI

45
Q

Molecular testing done to distinguish E. histolytica from E. dispar

A

PCR (Polymerase Chain Reaction)

46
Q

Diagnostic testing for Amebic Liver Abscess

A

Serological tests (ELISA): Enzyme-linked immunosorbent assay

47
Q

Non-invasive and sensitive methods in early

detection of ALA.

A

Ultrasound, CT scan, MRI

48
Q

Generic drug that is used for most protozoans including flagellates and ciliates

Drug of choice for trophozoites (invasive amebiasis, colitis, amebic dysentery, liver abscess, ameboma)

TROPHOZOITE

A

Metronidazole

49
Q

Drug of choice for healthy carriers/asymptomatic cyst
passers (people who are reservoir for the infection)
○ (Book) Also given after a course of metronidazole for invasive amebiasis

CYST

A

Diloxanide furoate

50
Q

EPIDEMIOLOGY OF AMEBVIASIS

A

Amebiasis: 1-5% worldwide

Particular in trophics

51
Q

3rd most important parasite

A

malaria, schistosomiasis, e. histolytica (amebiasis)

52
Q

Morphologically similar to E. histolytica, but differs on their ribosomal RNA and DNA

A

E.DISPAR AND E. MOSHKOVSKII

53
Q

E. moshkovskii differs biochemically and genetically because

A

Osmotolerant - able to grow at room temperature

54
Q

Cosmopolitan in distribution

More common than other human amebae

A

ENTAMOEBA COLI

55
Q

Most common amebic organism that can be identified in stools of patients.

A

ENTAMOEBA COLI

56
Q

Characteristics of E. coli cyst

A 
Large amoeba (10-35)
Max of 8 nuclei
Nuclei looks like pocket of coins
More granular cytoplasm
Splinter-like chromatoidal bodies
RBC is not present
57
Q

Nuclei looks like pocket of coins

A

E. coli cyst

58
Q

Characteristics of E. coli trophozoite

A

Trophozoites measure 15 to 50 μm in diameter

More vacuolated or granular endoplasm with bacteria and debris but no red blood cells

Narrower, less-differentiated ectoplasm

Broader and blunter pseudopodia used more for
feeding than locomotion

More sluggish, undirected movements

Thicker, irregular peripheral chromatin with a large, eccentric karyosome in the nucleus

59
Q

Appearance is relatively similar to E. histolytica apart from its smaller size.

Diminutive version of E. histolytica

Referred to as the “small race” of E. histolytica, it is differentiated primarily on the basis of the size.

A

ENTAMOEBA HARTMANNI

60
Q

E. hartmanni cyst characteristics

A

Size 4-10

Quadrinucleated

Rod-shaped chromatic material with rounded or squared ends

61
Q

Found in the intestines of pigs and monkeys

Rarely infects humans

A

Entamoeba Polecki

62
Q

Entamoeba Polecki trophozoite characteristics

A

Motility is sluggish

A small karyosome is centrally located in the nucleus.

UNINUCLEATED

chromatoidal bars are frequently angular or pointed.

Chromatoidal body looks like a chinese character
○ Criss-crossing of chromatoidal body???

In stained fecal smears, the nuclear membrane and
karyosome are very prominent.

63
Q

Occurs with the same frequency as Entamoeba coli

A

Endolimax nana

64
Q

Endolimax nana trophozoite characteristics

A

small (5-12)
Motility: sluggish
Blunt hyaline pseudopodia

Nucleus has a large, irregular karyosome

Food vacuoles found in the cytoplasm may contain
bacteria

65
Q

Endolimax nana cyst characteristics

A

same size as trophozoite

Quadrinucleated when mature

Often referred to as a cross-eyed cyst

Karyosome is very big, stained red and is
very prominent

66
Q

Ameba of swine (pigs)

A

IODAMOEBA BUTSCHLII

67
Q

IODAMOEBA BUTSCHLII TROPHOZOITES characteristics

A

Large, vesicular nucleus (uninucleated) with a large central karyosome; with achromatic granules

“Basket of Flowers”

No peripheral chromatin granules on the nuclear
membrane

9-14 um average diameter (ranging from 4 to 20 um)

68
Q

IODAMOEBA BUTSCHLII cyst characteristics

A

9 to 10 um in diameter

Uninucleated with large glycogen body which stains
dark brown with iodine

Large glycogen vacuole → especially in the cystic stage

It’s important to look at the cyst because you’ll see there the large glycogen vacuole

69
Q

Best demonstrated with iodine stain on the wet mount like your lugol’s iodine and MIF

A

IODAMOEBA BUTSCHLII

70
Q

Found in moutgh
Trophozoite measures 10 to 20 um
● It moves quickly, has numerous blunt pseudopodia
● Food vacuoles that contain cellular debris (mostly
leukocytes, which is characteristics of this species) and
bacteria are numerous
● Lives on the surface of gum and teeth, in gum pockets and
sometimes in the tonsillar crypts
● They are abundant in cases of oral disease
● It has no cyst stage
● Transmission is most probably direct: through kissing,
droplet spray, or by sharing utensils

A

ENTAMOEBA GINGIVALIS

71
Q

MOT of E. gingivalis

A

Direct contact : Kissing or droplets spray

72
Q

What are the Free-living pathogenic amebae

A

○ Acanthamoeba
○ Balamuthia
○ Naegleria

73
Q

These pathogenic amoeba are found free living in
water bodies like lakes, ponds, tapwaters and even in the air conditioned units that are not cleaned or maintained regularly

A

Free-living pathogenic amebae

○ Acanthamoeba
○ Balamuthia
○ Naegleria

74
Q

The Only free-living pathogenic ameba reported to cause disease in humans.

A

Naegleria Fowleri

75
Q

Three stages of Naegleria Fowleri

A

Feeding trophozoite stage
Dormant cyst stage
Transitional flagellate stage

76
Q

Naegleria fowleri trophozoites characteristics

A

Ameboid Trophozoite:

■ Cytoplasm: granular and contains many vacuoles.
■ Nucleus: single and large.
■ Dense karyosome.
■ Lacks peripheral chromatin.

77
Q

form of Naegleria fowleri produced when conditions are not favorable.

A

Dormant cyst stage

78
Q

form of Naegleria fowleri
that are Thermophilic organisms thriving best in hot
springs and warm aquatic environment.

A

Transitional flagellate stage

79
Q

Means of transmission of Naegleria fowleri

A

Entry into the body: Olfactory Epithelium, Respiratory

Tract, Skin and Sinuses

80
Q

Causes Primary Amebic

Meningoencephalitis (PAM)

A

Naegleria Fowleri

81
Q

Diagnostically can find the trophozoite in the CSF

A

Naegleria Fowleri

82
Q

meningitis symptoms: high

grade fever, seizures, headache

A

Primary Amebic Meningoencephalities (PAM)

83
Q

MOT of ACANTHAMOEBA SPP.

A

through eyes
Nasal passages to lower respiratory tract
Ulcerated or broken skin

84
Q

highly resilient which transforms when environmental conditions are not favorable

A

ACANTHAMOEBA SPP. cyst

85
Q

Free-living pathogenic ameba that causes Granulomatous Amebic Encephalitis (chronic; slow in progression) & Amebic Keratitis

A

ACANTHAMOEBA SPP.

86
Q

very difficult to differentiate this from TB encephalitis, moreso TB is more common than this Amebic Encephalitis.

A

Granulomatous Amebic Encephalities

87
Q

Signs and symptoms: generally related to destruction of brain tissue and the associated meningeal irritation.

Systemic manifestations early in the course include fever, malaise, and anorexia

Neurologic symptoms may include increased sleeping time, severe headache, mental status changes, epilepsy, and coma.

A

Granulomatous Amebic Encephalities

88
Q

It is a ubiquitous ameba that has many reservoirs in nature like other animals.

A

ACANTHAMOEBA SPP.

89
Q

Can cause Amebic keratitis or the infection of cornea

A

ACANTHAMOEBA SPP.

90
Q

Both the trophozoite and the cystic stage can actually be the mode of infection, and they enter the human in various ways.

A

ACANTHAMOEBA SPP.

91
Q

ACANTHAMOEBA SPP. trophozoite characteristic

A

thorn-like appendage called acanthopodia

92
Q

Diagnosis of GAE

A

Biopsy
Corneal Scarpings
Culture
Molecular methods

Parasitology Lec (5 decks)

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