6. Flagellates

Question 1

a whiplike structures responsible for the
movement of the flagellates (trophozoite form).

Answer 1

flagella

Question 2

Flagellates reside mainly in the:

Answer 2

✓Small intestines
✓Cecum
✓Colon
✓Duodenum (Giardia intestinalis)

Question 3

are equipped
with thick, protective cell walls
and can survive in the outside
environment (similar to amebas).

Answer 3

flagellate cysts

Question 4

finlike structure connected to the outer edge of some flagellates

Answer 4

Undulating membrane

Question 5

rodlike support structure found in some flagellates

Answer 5

Axostyle

Question 6

Flagellate identification:

Answer 6

✓Use of saline
✓Iodine wet preparations
✓Permanent stain

Question 7

➢Common disease:
* Giardiasis, traveler’s diarrhea
➢Initially known as:
* Cercomonas intestinalis
➢Stiles coined the term:
* Giardia lamblia
➢Some also consider the term:
* Giardia duodenale (as a synonym)

Answer 7

Giardia intestinalis

Question 8

Giardia intestinalis
Trophozoite

Answer 8

➢Shape
* Pear-shaped, teardrop
➢Motility
* Falling leaf
➢Appearance
* Bilaterally symmetrical

Question 9

Giardia intestinalis
Cysts

Answer 9

➢Shape
* Ovoid
➢Nuclei
* Immature cyst, two mature cysts, four central
karyosomes, NO peripheral chromatin
➢Cytoplasm
* Retracted from cell wall

Question 10

Giardia intestinalis
Laboratory Diagnosis

Answer 10

➢Enterotest - duodenal contents using string test.
➢Fecal antigen detection by Enzyme Immunoassays (EIA) and Enzyme-linked Immunosorbent Assay (ELISA)
➢Direct Fluorescence detection (Giardia and Cryptosporidium)
➢Giardia western immunoblotting (blot)
➢Real-time polymerase chain reaction (RT-PCR) – molecular method sensitive enough for environmental
monitoring.

Question 11

Considered to be one of the most common intestinal
parasite, especially among children.

Answer 11

Giardia intestinalis

Question 12

Found worldwide in lakes, streams, and other water
sources.

Answer 12

Giardia intestinalis

Question 13

are resistant to the routine
chlorination procedures.

Answer 13

Giardia intestinalis cyst

Question 14

_____ as well as _____ of this water is crucial to obtain adequate drinking water.

Answer 14

• Filtration
• Chemical treatment

Question 15

now considered to be
the only known pathogenic intestinal flagellate

Answer 15

Giardia intestinalis

Question 16

also known Traveler’s disease

Answer 16

Giardia intestinalis

Question 17

Typical incubation period of Giaria intestinalis

Answer 17

10-36 days

Question 18

Giardia is a self-limiting condition that typically is
over in after onset.

Answer 18

10 to 14 days

Question 19

Patients with _____ or an
______ appear to be
particularly susceptible to reoccurring infection.

Answer 19

• intestinal diverticuli
• immunoglobulin A (IgA) deficiency

Question 20

Primary choice of treatment for G. intestinalis infection
(according to CDC):

Answer 20

✓Metronidazole, Tinidazole, and Nitazoxanide

Question 21

G. intestinalis is discovered in ____ by ____ when he examined a sample of his own stool.

Answer 21

• 1681
• Anton van
  Leeuwenhoek

Question 22

First known rough description of Giardia was written by the
Secretary of the Royal Society of London

Answer 22

Robert Hooke

Question 23

Giardia trophozoites have often been
referred to as resembling an

Answer 23

old man’s face with whiskers

Question 24

are both known to be
carriers of double-stranded RNA
viruses.

Answer 24

G. intestinalis and Trichomonas
vaginalis

Question 25

Chilomastix mesnili Trophozoite

Answer 25

➢Shape – Pear-shaped ➢Motility – Stiff, rotary, directional

Question 26

Chilomastix mesnili cysts

Answer 26

➢Shape – Lemon-shaped, with a clear hyaline knob extending from the anterior end ➢Nuclei – One, with large central karyosome, No peripheral chromatin

Question 27

(Chilomastix mesnili) often demonstrate the organism’s features most clearly.

Answer 27

Iodine wet preparations

Question 28

➢Once inside the human body, it is known to reside in the mucosal crypts of the large intestine.

Answer 28

Dientamoeba fragilis

Question 29

One unproven theory suggests that is transmitted via the eggs of helminth parasites such as Enterobius vermicularis and Ascaris lumbricoides.

Answer 29

D. fragilis

Question 30

Dientamoeba fragilis Treatment

Answer 30

✓Iodoquinol – treatment of choice ✓Tetracycline – acceptable alternative treatment

Question 31

Feature diagnostic for the identification of D. fragilis.

Answer 31

Hakansson phenomenon

Question 32

numerous granules are present in this stage and exhibit Brownian motion

Answer 32

Hakansson phenomenon

Question 33

the erratic random movement of microscopic particles in a fluid

Answer 33

Brownian motion

Question 34

Enteromonas hominis Trophozoite

Answer 34

➢Shape – Oval; sometimes half circle ➢Motility – Jerky

Question 35

Enteromonas hominis Cyst

Answer 35

➢Nuclei – One to four, Binucleated and quadrinucleated nuclei located at opposite ends, Central karyosome. No peripheral chromatin.

Question 36

Enteromonas hominis treatment

Answer 36

not indicated (nonpathogen)

Question 37

Retortamonas intestinalis Trophozoite

Answer 37

➢Shape – Ovoid ➢Motility – Jerky ➢Nuclei – One, with small central karyosome. Ring of chromatin

Question 38

Retortamonas intestinalis Cyst

Answer 38

➢Shape – Lemon-shaped, pear-shaped ➢Nuclei – One, located in anterior-central region with central karyosome. May be surrounded by a delicate ring of chromatin granules.

Question 39

Two fused fibrils resembling a bird's beak in the anterior nuclear region

Answer 39

Retortamonas intestinalis

Question 40

Trichomonas hominis Trophozoite

Answer 40

➢Shape – Pear-shaped ➢Motility – Nervous, jerky ➢Nuclei – One, with a small central karyosome. No peripheral chromatin.

Question 41

Common Disease: Persistent urethritis, Persistent vaginitis, Infant Trichomonas vaginalis infection

Answer 41

Trichomonas vaginalis

Question 42

Trichomonas vaginalis Trophozoite

Answer 42

➢Shape – Ovoid, round or pear-shaped ➢Motility – Rapid, Jerky ➢Nuclei – One, ovoid, nondescript ➢Flagella – All originating anteriorly: Three to five extending anteriorly, One extending posteriorly.

Question 43

➢Trophozoites reside on the ____ of the vagina in infected women. ➢Trophozoites multiply by _____ and feed on local bacteria and leukocytes. ➢Trophozoites thrive in a _____ or _____ environment. ➢Most common infection site of T. vaginalis in male: _____

Answer 43

- mucosal surface - longitudinal binary fission - slightly alkaline or slightly acidic pH - Gland region and the epithelium of the urethra

Question 44

Trophozoites are by nature hardy and resistant to changes in their environment.

Answer 44

Trichomonas vaginalis

Question 45

Persistent vaginitis incubation period

Answer 45

4 to 28 days

Question 46

Trichomonas vaginalis Treatment of choice

Answer 46

Metronidazole

Question 47

Trichomonas tenax Trophozoite

Answer 47

➢Shape – Oval, pear-shaped ➢Nuclei – One, ovoid nucleus; consist of vesicular region filled with chromatin granules.

Question 48

Trichomonas tenax specimen of choice

Answer 48

Mouth scrapings