[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

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CHAPTER 4 The Flagellates
Notes of Interest and New Trends
Infections with T. vaginalis are generally considered
to be a nuisance and not a major pathogenic
process.
There is evidence to suggest a connection
between T. vaginalis infections and cervical
carcinoma.
Quick Quiz! 4-21
This prominent structure found in T. vaginalis trophozoites
that often extends beyond the body provides
the parasite with support. (Objective 4-9A)
A. Nucleus
B. Axostyle
C. Axoneme
D. Granule
Quick Quiz! 4-22
The cyst morphologic form is not known to exist in
the life cycle of T. vaginalis. (Objective 4-5C)
A. True
B. False
Quick Quiz! 4-23
T. vaginalis may be recovered in which of the following
specimen types? (Objective 4-8)
A. Spun urine
B. Vaginal discharge
C. Stool
D. Urethral discharge
E. More than one of the above: ____________
(specify)
Quick Quiz! 4-24
All cases of T. vaginalis infection result in symptomatic
vaginitis in women and urethritis in men. (Objectives
4-6 and 4-7)
A. True
B. False
Quick Quiz! 4-25
Infant infections with T. vaginalis tend to affect which
of the following of these body areas? (Objective 4-6)
A. Respiratory and genital
B. Genital and intestinal
C. Intestinal and eye
D. Respiratory and eye
LOOKING BACK
The typical characteristics common to all flagellates
include size, shape, and nuclear structures.
In addition, most have structures specific to one
or just a few of the flagellates, such as varying
lengths of the undulating membrane, axonemes,
or a spiral groove. In summary, three comparison
drawings are included at the end of this chapter
for easy reference—the flagellate trophozoites
found in stool, the flagellate cysts found in stool,
and atrial flagellate trophozoites.
The importance of careful and thorough
screening of all samples for the presence of parasites
cannot be emphasized enough. Just as
amebas may be diagnosed by characteristics
typical to their class, so also may flagellates. The
composite drawings are provided to serve as a
resource tool to help practitioners in the identification
of the intestinal and atrial flagellates.
TEST YOUR KNOWLEDGE!
4-1. Match each of these flagellate parasites
(column A) with its corresponding description
(column B). (Objective 4-9)
Column A
___ A. Dientamoeba
fragilis
___ B. Trichomonas
tenax
___ C. Giardia
intestinalis
Column B
1. Lemon-shaped
cyst
2. Trophozoite has
a ventrally
located sucking
disc
3. Transmitted by
helminth ova