Parasitology Part 1 Amoeba that inhibit the gastrointestinal tract of
man are non-motile, non-feeding, and infective
during which stage?*
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Pseudopod
Cyst
The motile, reproducing, feeding stage of the
protozoans is which of the following?*
Trophozoite
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Cryptozoite
Cyst
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Trophozoite
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Ova (egg)
Which of these trophozoites, when acting as a
Adult worm
pathogen, is likely to ingest red blood cells of
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Entamoeba coli
Which of the following organs of the body is Entamoeba hartmanni
most often involved in extraintestinal
Entamoeba histolytica
amoebiasis?*
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Endolimax nana
Lungs
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Kidneys
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Pancreas
The point of differentiation between Entamoeba
Liver
histolytica and Entamoeba hartmanni is: *
Correct answer
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Liver
Presence of peripheral chromatin
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Presence of chromatoid bodies
Only one possesses a cyst form Acanthamoeba castellanii
Size Untitled Section
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Size
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large glycogen vacuole that stains deeply with
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iodine belong to:*
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Failure to find bacteria in purulent spinal fluid
Endolimax nana
should alert one to the possibility of an infection
with:*
0/2 Iodamoeba butschlii
Viruses Dientamoeba fragilis
Entamoeba coli
Amoeba Correct answer
Flagellates Iodamoeba butschlii
Worms Untitled Section
Correct answer 0 of 2 points
Amoeba
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enter the body through the:*
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Mouth
Which of the following would have a double-
walled, wrinkled cyst form?*
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Naegleria fowleri Urine
Entamoeba hartmanni Joint fluid
Correct answer
Acanthamoeba castellanii Nasal mucosa
Dientamoeba fragilis Untitled Section
Correct answer 0 of 2 points
Cytostome/trophozoite
In which specimen are Acanthamoeba and Ventral sucking disk/trophozoite
Naegleria usually found?*
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Blood
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Cerebrospinal fluid
Which of the following protozoa have an
Urine undulating membrane?*
Joint fluid 0/2
Correct answer Trichomonas
Cerebrospinal fluid Trypanosoma
Untitled Section Chilomastix
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Trichomonas and Trypanosoma
Which of the following are often mistaken for Correct answer
cysts of amoeba?*
Trichomonas and Trypanosoma
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Blastocystis hominis
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Calcium carbonate crystals
A pear-shaped flagellate with jerky motility that
Ammonium magnesium phosphate crystal is found in a urine specimen is identified as: *
Epithelial cells 2/2
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2 of 2 points Trichomonas vaginalis
Which of the following is pathognomonic for Escherichia coli
Giardia lamblia and the stage it is found in?*
Leptospira
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Spiral groove/trophozoite
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Undulating membrane/cyst
Eighty (80) percent of the trophozoites of Tsetse fly (Glossina)
Dientamoeba fragilis have: *
Ticks
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Correct answer
2 nuclei
Tsetse fly (Glossina)
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3 nuclei
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1 nuclei
No nuclei
How is Trypanosma cruzi transmitted?*
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Inhalation
Bite of the tsetse fly
The only bilaterally symmetrical protozoan is:*
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Bite of the reduviid bug
Trichomonas
Sexual contact
Dientamoeba
Correct answer
Giardia
Bite of the reduviid bug
Balantidium
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Correct answer
Giardia
In the laboratory diagnosis of Leishmania
Untitled Section donovani, which is the preferred specimen in
which to find Leishman-Donovan bodies?*
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Bone marrow
Which of the following is the vector of African
sleeping sickness?* Blood
0/2 Vaginal secretions
Reduviid bug (Triatoma) Cerebrospinal fluid
Sandfly (Phlebtomus)
Correct answer
Bone marrow Which nucleus of the trophozoite of
Balantidium coli is the reproductive one?*
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Micronucleus
Which of the following is the only ciliate that is
pathogenic in humans? * Macronucleus
0/2 Both of these
Babesia None of these
Isospora Untitled Section
Balantidium coli 0 of 2 points
Entamoeba coli
Which of the malarial organisms presents as
pale, very AMOEBOID RING TROPHOZOITE,
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infecting a large pale red blood cell with dot of
Balantidium coli hemoglobin?*
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Plasmodium malariae
Structure used for motility of Balantidium coli:*
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Flagella Plasmodium vivax
Correct answer
Cilia Plasmodium vivax
Pseudopodia Untitled Section
Undulating membrane 0 of 2 points
Correct answer
Cilia Which of the malarial organism preferentially
invades reticulocytes?*
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Plasmodium falciparum Plasmodium vivax
Plasmodium malariae Plasmodium falciparum
Plasmodium vivax Correct answer
All of the above Plasmodium malariae
Correct answer Untitled Section
Plasmodium vivax 0 of 2 points
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0 of 2 points Which malarial organism features ring
trophozoites that have double chromatin dots,
applique forms, and often have multiple
The malarial organism whose schizont parasites in the infected red blood cells?*
resembles a “fruit pie” in which the merozoites
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form a rosette around the malarial pigment is:*
Plasmodium vivax
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Plasmodium falciparum
Plasmodium malariae
Plasmodium malariae
Plasmodium vivax
Plasmodium ovale
Plasmodium ovale
Correct answer
Plasmodium falciparum
Plasmodium falciparum
Correct answer
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Plasmodium malariae
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Which malarial organism has large, coarse, red
dots within a large, pale red blood cell with
Which malarial organism characteristically has a fimbriated edges?*
BAND FORM trophozoite stretching across the
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red blood cell?*
Plasmodium vivax
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Plasmodium malariae
Plasmodium falciparum
Plasmodium ovale
Plasmodium ovale 0 of 2 points
Plasmodium malariae
Correct answer What is the infective stage of malarial parasite
to humans?*
Plasmodium ovale
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Gametocytes
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Cryptozoites
Schizonts
The sexual reproduction cycle in Plasmodium
and coccidian is referred to as:*
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Sporogony Correct answer
Schizogony Sporozoites
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None of the above
Correct answer In which type of malaria is there synchronized
rupture of the red blood cells every 72 hours?*
Sporogony
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P. falciparum
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P. ovale
P. vivax
What is the infective stage of malarial parasite
to the vector?*
2/2 P . malariae
Cryptozoites Correct answer
Trophozoites P . malariae
Gametocyte Untitled Section
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Ookinete
Untitled Section Which hemoglobin is incompatible with malaria
parasite survival?*
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Hb CC Cat
Hb F Chicken
Correct answer
Hb SS Cat
Hb A Untitled Section
Correct answer 0 of 2 points
Hb SS
Untitled Section What constitutes a positive result in the Sabin-
Feldman dye test?*
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Toxoplasma becomes nonmotile
What is the name of the laboratory test that
allows laboratory-bred reduviid bugs to feed on Toxoplasma can no longer be demonstrated as
patients suspected of having Chagas’ disease?* an intracellular organism
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Complement fixation Toxoplasma loses its affinity for methylene blue
dye
The mouse into which the immune serum is
Serodiagnosis
injected does not die from toxoplasmosis
Xenodiagnosis
Correct answer
Western blot
Toxoplasma loses its affinity for methylene blue
Correct answer dye
Xenodiagnosis Untitled Section
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Which of the following tests is used for the
detection of Cryptosporidium?*
What is both the definitive and intermediate
host of Toxoplasma gondii?* 0/2
0/2 Sabin-Feldman dye test
Dog
Cow G-6-PD test
Xenodiagnosis Cryptosporidium and other coccidia
Sheather’s sugar flotation Untitled section
Correct answer 0 of 2 points
Sheather’s sugar flotation
Untitled Section Microsporidial infections can be confirmed
using:*
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Light microscopy and modified trichrome stains
Direct examination of stool specimens stained
with iodine make the trophozoite of the Phase contrast microscopy and routine
protozoa stain what color?* trichrome stains
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Yellow Electron microscopy and modified acid-fast
stains
Brown
Fluorescence microscopy and hematoxylin
stains
Trophozoites are destroyed by iodine
Correct answer
Do not stain
Light microscopy and modified trichrome stains
Correct answer
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Trophozoites are destroyed by iodine
An infection with microsporidia can be
Untitled Section confirmed using modified trichrome stains (10X
the normal dye content found in routine
0 of 2 points trichrome stains) and light microscopy. The
internal polar tubule will be visible within some
of the spores; this will serve as confirmation of
The modified acid-fast stain is most often used the infection.
in parasitology to identify:*
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Protozoan cysts and trophozoites
What morphological characteristic differentiates
Helminth eggs trichomonads from other intestinal flagellates?*
Plasmodium 2/2
Cryptosporidium and other coccidia Sucking disc
Correct answer Undulating membrane
Shape of the karyosome
Cytostome Distinguishing surface antigens by immunologic
assays
Axonemes
Correct answer
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Distinguishing surface antigens by immunologic
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assays
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Shown to be related to GAY BOWEL
E. histolytica and E. dispar cannot be
SYNDROME:*
morphologically differentiated. The cyst stage of
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located karyosome. E. histolytica is a well
Giardia lamblia recognized intestinal parasite, whereas E. dispar
is considered nonpathogenic. Immunologic
assays to detect antigens or molecular biology
Entamoeba histolytica assays are necessary to differentiate these two
Balantidium coli species.
Isospora belli Untitled Section
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Important risk factors for Giardiasis include:
poor hygiene, poor sanitation, overcrowding, Which of the following is the preferred
immunodeficiency, bacterial and fungal anticoagulant for preparing blood smears for
overgrowth in the small intestine, and diagnosing malaria?*
homosexual practices. Giardiasis has been
shown to be related to the “GAY BOWEL 2/2
SYNDROME.” EDTA
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0 of 2 points Heparin
Sodium citrate
Which of the following is the most important Sodium fluoride
feature in differentiating cysts of Entamoeba
histolytica from E. dispar?* Feedback
0/2 Collection of blood by finger stick is preferred for
preparing blood smears for the detection of
Number of nuclei malaria. When a venipuncture is performed, the
preferred anticoagulant for malarial blood
smears is EDTA. Heparin can be used, but it may
Size of the cyst cause distortion of some parasite forms.
Untitled Section Trichrome-stained smear
2 of 2 points Feedback
Because there is no known cyst form, the best
technique to recover and identify D. fragilis
A free-living ameba that causes primary amebic
trophozoites would be the trichrome-stained
meningoencephalitis is:*
smear.
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Dientamoebafragilis
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Entamoeba coli
Entamoeba histolytica
A Gram stain from a gum lesion showed what
Naegleria fowleri appeared to be amoebae. A trichrome smear
showed amoebae with a single nucleus and
partially digested PMNs. The correct
Feedback identification is:*
Naegleria fowleri is found in freshwater ponds 2/2
and lakes, especially those with disturbed or Trichomonas tenax
suspended soil. It has caused a number of cases
of meningoencephalitis in people who have Entamoeba histolytica/E. dispar
swum in these bodies of water. Essentially, all
Entamoeba polecki
these infections have been fulminating and
fatal, and they are often not diagnosed until Entamoeba gingivalis
autopsy.
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E. gingivalis is known to be an inhabitant of the
mouth and is characterized by morphology that
resembles Entamoeba histolytica/E. dispar.
Which of the following is the best technique to
However, E. gingivalis tends to ingest PMNs,
identify Dientamoeba fragilis in stool?*
whereas Entamoeba histolytica/E. dispar do
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Formalin concentrate Untitled section
Trichrome-stained smear 0 of 2 points
Modified acid-fast–stained smear
Giemsa stain In an outbreak of diarrheal disease traced to a
municipal water supply, the most likely
causative agent is:*
Correct answer 0/2
Cryptosporidium spp.
Cystoisospora belli Early ring stages of the fifth human malaria,
Plasmodium knowlesi, resemble those of:*
Entamoeba histolytica
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Plasmodium malariae
Dientamoeba fragilis
Correct answer
Plasmodium ovale
Cryptosporidium spp.
Plasmodium falciparum
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Plasmodium vivax
Cryptosporidium oocysts have been transmitted
through contaminated municipal water Correct answer
supplies. Such outbreaks have been well
Plasmodium falciparum
documented.
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The early ring stages of Plasmodium knowlesi
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resemble those of P. falciparum.
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Plasmodium vivax and Plasmodium ovale are
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similar because they:*
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Older developing stages (trophs, schizonts) of
Exhibit Schüffner’s dots and have a true relapse
the fifth human malaria, Plasmodium knowlesi,
in the life cycle
resemble those of:*
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Have no malarial pigment and multiple rings
Plasmodium malariae
Have true stippling, do not have a relapse stage,
Plasmodium ovale
and infect old red cells
Plasmodium falciparum
Commonly have appliqué forms in the red cells
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Plasmodium vivax
Both P. vivax and P. ovale infect young red cells,
have true stippling (Schüffner’s dots), contain Correct answer
malarial pigment, and have a true relapse stage
in the life cycle. Plasmodium malariae
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The older developmental stages of Plasmodium
knowlesi (trophs, schizonts) resemble those
seen in infections with P. malariae (band forms,
rosette schizonts).
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Autofluorescence requires no stain and is
recommended for the identification of:*
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Entamoeba histolytica cysts
Toxoplasma gondii tachyzoites
Dientamoeba fragilis trophozoites
Cyclospora cayetanensis oocysts
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Autofluorescence requires no stain and is often
recommended for confirmation of Cyclospora
cayetanensis oocysts.
