Exercise No. 6b

Question 1

Entamoeba histolytica Trophozoite Size

Answer 1

10-60 µm (ave: 15-20 µm)

Question 2

Entamoeba histolytica Trophozoite Motility and Pseudopodia

Answer 2

Progressive, rapid, unidirectional motility; with hyaline, fingerlike pseudopodia formed rapidly

Question 3

Entamoeba histolytica Trophozoite Nucleus Number

Answer 3

1

Question 4

Entamoeba histolytica Trophozoite Peripheral chromatin

Answer 4

Fine granules, uniform in size and usually evenly distributed; may have beaded appearance

Question 5

Entamoeba histolytica Trophozoite Karyosome

Answer 5

Small, compact, centrally located

Question 6

Entamoeba histolytica Trophozoite Linin network

Answer 6

The space between the karyosome and the nuclear membrane is traversed by fine thread of linin network giving a radial spokeswheel or cartwheel appearance.

Question 7

Entamoeba histolytica Trophozoite Cytoplasm Appearance

Answer 7

Finely granular, “ground-glass” appearance; clear differentiation into a clear ectoplasm and more granular endoplasm; if present, vacuoles are usually very small

Question 8

Entamoeba histolytica Trophozoite Inclusions

Answer 8

RBCs are diagnostic; few ingested bacteria or debris in vacuoles

Question 9

Entamoeba histolytica Cyst Size

Answer 9

10-20 µm (12-15 µm)

Question 10

Entamoeba histolytica Cyst Shape

Answer 10

Usually spherical

Question 11

Entamoeba histolytica Cyst Nucleus Number

Answer 11

1-4; mature cyst contains 4 nuclei

Question 12

Entamoeba histolytica Cyst Peripheral chromatin

Answer 12

Similar to that seen in trophozoite

Question 13

Entamoeba histolytica Cyst Karyosome

Answer 13

Similar to that seen in trophozoite

Question 14

Entamoeba histolytica Cyst Cytoplasm Chromatoidal bodiesMay be present; usually elongate with blunt, rounded, smooth ends (cigarshaped); may be round or oval.

Question 15

Entamoeba histolytica Cyst Glycogen vacuole

Answer 15

May be present, usually diffuse, stains reddish brown with iodine.

Question 16

is morphologically indistinguishable from E. histolytica and should be reported as E. histolytica/E. dispar unless ingested red blood cells are seen, suggesting E. histolytica infection.

Answer 16

Entamoeba dispar

Question 17

The DNA and ribosomal RNA , and isoenzyme pattern of (?) is different from that of E. histolytica.

Answer 17

E. dispar

Question 18

Unlike E. histolytica, E. dispar is (?).

Answer 18

nonpathogenic.

Question 19

The ratio of E. dispar to E. histolytica in most developing countries can be as high as (?) in a community setting.

Answer 19

10:1

Question 20

It is performed for diagnosis of intestinal amoebiasis.

Answer 20

Stool examination

Question 21

It is not of value in the diagnosis of extraintestinal amoebiasis.

Answer 21

Stool examination

Question 22

E. histolytica cyst can be detected in stool in less than 15% cases of amoebic hepatitis.

Answer 22

Stool examination

Question 23

: This is a standard method for routine O & P exam. Trophozoites are primarily recovered from stools that are of soft, liquid, or loose consistency.

Answer 23

Formed stool specimens are more likely to contain cysts.

Question 24

Saline mount of fresh unfixed stool demonstrates motile trophozoites, or cysts while iodine preparation primarily demonstrates the cysts only.

Answer 24

Direct fecal smear (DFS)

Question 25

When patient is suspected of having intestinal amoebiasis, 6 specimens is recommended (however, is rarely requested) and collected on separate days within 14-day period: 3 specimens collected from normal bowel movement and 3 specimens collected after catharsis/purge.

Answer 25

Direct fecal smear (DFS)

Question 26

Formed stool specimens are more likely to contain cysts.

Answer 26

Direct fecal smear (DFS)

Question 27

Few, Numerous

Answer 27

Bacteria

Question 28

Scanty, well-preserved; Numerous, degenerated

Answer 28

Pus cells

Question 29

Often in rouleaux; Unaltered, scattered

Answer 29

RBC

Question 30

NOT a feature; May be numerous (may have RBC)

Answer 30

Macrophage

Question 31

May be present; Absent

Answer 31

Charcot-Leyden crystals

Question 32

Present; Absent

Answer 32

Trophozoite

Question 33

There are two types of concentration procedures:

Answer 33

flotation and sedimentation

Question 34

Cysts may be seen and identified, but trophozoites are not likely to be seen. Therefore, this is recommended for isolation and identification of amoebae in non-diarrheic stool.

Answer 34

Stool concentration

Question 35

It is considered the best practice in the diagnosis of protozoa because it allows examination and recognition of the detailed morphology of the trophozoites or cysts.

Answer 35

Permanent staining

Question 36

It provides contrasting colors for the parasites and the background. The parasite is examined under high magnification by oil-immersion technique.

Answer 36

Permanent staining

Question 37

The parasite is examined under high magnification by (?) technique.

Answer 37

oil-immersion

Question 38

Blue-green, sometimes light pink or with a tinge of purple; Slightly more purple

Answer 38

TRICHROME

Question 39

Red, sometimes with a tinge of purple

Answer 39

TRICHROME

Question 40

Green, provides nice contrast with the protozoa

Answer 40

TRICHROME

Question 41

Blue-gray; Blue-gray

Answer 41

IRON HEMATOXYLIN

Question 42

Darker than cytoplasm, bluegray to black

Answer 42

IRON HEMATOXYLIN

Question 43

Lighter shade of blue-gray

Answer 43

IRON HEMATOXYLIN

Question 44

Scraping obtained is often contributory.

Answer 44

Examination of sigmoidoscopy specimen

Question 45

Examination method includes a direct wet mount and permanent staining.

Answer 45

Examination of sigmoidoscopy specimen

Question 46

Liver abscess material, may be processed and examined in the same manner. Microscopic examination of pus aspirated from liver abscess may demonstrate trophozoite of E. histolytica in less than 20% cases.

Answer 46

Examination of sigmoidoscopy specimen

Question 47

In case of liver abscess, when diagnostic aspiration is done, the pus obtained from the center of the abscess may not contain amoeba as they are confined to the periphery.

Answer 47

Examination of sigmoidoscopy specimen

Question 48

The fluid draining after a day or two is more likely to contain the trophozoite. Aspirates from the margins of the abscess would also show the trophozoites.

Answer 48

Examination of sigmoidoscopy specimen

Question 49

Cysts are never seen in extraintestinal lesions. Trophozoite of E. histolytica may be demonstrated in liver biopsy specimen, in case of hepatic amoebiasis or amoebic hepatitis.

Answer 49

Examination of sigmoidoscopy specimen

Question 50

It is a more sensitive method in diagnosing chronic and asymptomatic intestinal amoebiasis.

Answer 50

Stool Culture

Question 51

(?) yields higher positivity for E. histolytica as compared to direct examination.

Answer 51

Culture of stools

Question 52

Media used for polyxenic culture include:

Answer 52

- Boeck and Drbohlav's biphasic medium - NIH polygenic medium - Craig's medium - Nelson's medium - Robinson's medium - Balamuth's medium.

Question 53

Medium for axenic culture:

Answer 53

- Diamond's medium

Question 54

Amebic antibodies appear in serum only in late stages of intestinal amebiasis.

Answer 54

Antibody detection

Question 55

Test for antibodies in serum help in the diagnosis of mainly extraintestinal infections.

Answer 55

Antibody detection

Question 56

An(?) for stool is now commercially available.

Answer 56

ELISA-based assay

Question 57

In reference diagnostic laboratories, molecular analysis by conventional PCR-based assays or real-time PCR is the method of choice for discriminating between E. histolytica and E. dispar

Answer 57

Molecular diagnosis

Question 58

X-ray, ultrasonography (USG), computed tomography (CT) scan, or magnetic resonance imaging (MRI) of liver may be found useful in detection of amebic liver abscess.

Answer 58

Radiologic examination

Question 59

The three genera of amoeba can be distinguished from each other by the structure of nucleus.

Answer 59

Small compact karyosome; Large irregular karyosome; Large circular karyosome

Question 60

(?) central or eccentrically located; nuclear membrane lined with peripheral chromatin.

Answer 60

Small compact karyosome of Commensal Amoebae

Question 61

(?) attached to the nuclear membrane by fibrils radiating to the periphery; no peripheral chromatin.

Answer 61

Large irregular karyosome of Commensal Amoebae

Question 62

(?) surrounded by refractile achromatic granules called periendosomes; no peripheral chromatin.

Answer 62

Large circular karyosome of Commensal Amoebae

Question 63

5-12 µm (ave. 8-10 µm)

Answer 63

Entamoeba hartmanni

Question 64

10-50 µm (ave. 20-25 µm)

Answer 64

Entamoeba coli

Question 65

5-20 µm (ave. 10-15 µm)

Answer 65

Entamoeba gingivalis

Question 66

6-15 µm (ave. 8-10 µm)

Answer 66

Endolimax nana

Question 67

6-20 µm (ave.12-15 µm)

Answer 67

odamoeba butschlii

Question 68

Less progressive motility; with hyaline, fingerlike pseudopodia formed rapidly

Answer 68

Entamoeba hartmanni

Question 69

Nonprogressive, sluggish, nondirectional motility; with blunt, usually granular pseudopodia formed slowly

Answer 69

Entamoeba coli

Question 70

Moderately active, progressive; with multiple pseudopodia , vary from long, and lobose to short and blunt, often formed rapidly

Answer 70

Entamoeba gingivalis

Question 71

Sluggish, moderately progressive; with blunt, hyaline pseudopodia formed slowly

Answer 71

Iodamoeba butschlii

Question 72

Fine granules, uniform in size and usually evenly distributed; may have beaded appearance

Answer 72

Entamoeba hartmanni

Question 73

Usually clumped and unevenly arranged on the membrane; may also appear as solid, dark ring with no beads or clumps

Answer 73

Entamoeba coli

Question 74

Fine granules, closely packed

Answer 74

Entamoeba gingivalis

Question 75

NONE

Answer 75

Endolimax nana, Iodamoeba butschlii

Question 76

Small, compact, centrally located, may be eccentric

Answer 76

Entamoeba hartmanni

Question 77

Moderately large, not compact, usually eccentrically located

Answer 77

Entamoeba coli

Question 78

Small, welldefined, usually centrally located

Answer 78

Entamoeba gingivalis

Question 79

Large, irregularlyshaped,centrally or eccentrically located; may appear “blotlike”; many nuclear variations are common

Answer 79

Endolimax nana

Question 80

Large, usually central, surrounded by refractile achromatic granules that are difficult to see

Answer 80

Iodamoeba butschlii

Question 81

Finely granular, “ground-glass” appearance; clear differentiation into a clear ectoplasm and more granular endoplasm; if present, vacuoles are usually very small

Answer 81

Entamoeba hartmanni

Question 82

Granular, with little differentiation between ectoplasm and endoplasm; with few to numerous vacuoles

Answer 82

Entamoeba coli

Question 83

Finely granular, vacuolated

Answer 83

Entamoeba gingivalis

Question 84

Granular, vacuolated

Answer 84

Endolimax nana