Parasitology Exam review Exam I Questions
If a parasite has a sexual stage, the host in which that stage occurs is known as the -
answersDefinitive host
If an infected host is described as a "dead end" host, it means - answersThe parasite
cannot complete its life cycle in that host
The value of using polyvinyl alcohol (PVA) as a stool fixative is that - answersSmears
for a "permanent stain", eg trichrome, can be made from it
In the formalin-ethyl acetate procedure concentration procedure, parasitic structures are
expected to be present in which of the four layers after centrifugation -
answersSediment
In the parts of the US with temperate climate, the most frequently encountered enteric
parasites are... - answersCryptosporidium and Giardia
In a hospital setting, a specimen of unformed feces is brought to the lab. immediately
after collection; you know that it cannot be examined immediately, so you would... -
answersMix a sample of it into 10% formalin and a sample into polyvinyl alcohol (PVA)
An outpatient comes to the laboratory with a physician's orders for "O & P x3" No
instructions have been given to the patient other than to get collection kits from the lab.
You give the patient collection kits and advise the patient to... - answersCollect 3
specimens 2 days apart, say Monday, Wednesday, and Friday
With the increasing use of immunoassays in parasitology, of concern is/are -
answersThe compatibility of the fixative(s) used to preserve the fecal specimen
The possibility of "missing" (not detecting) parasites other than those detected by the
immunoassay
"Non-traditional" parasitology stain(s) that now have an important role in parasitology
microscopy include - answersCalcofluor white stain; Modified (reduced decolorization)
acid-fast stain; and Acridine orange stain
What type of infections may be caused by all 3 of the genera of free-living amebae,
Naegleria, Acanthamoeba, and Balamuthia - answersCentral nervous system (CNS)
infections
, In which of the free-living ameba genera is there a flagellate stage - answersNaegleria
Cysts of the free-living amebae typically have which of the following properties -
answersResistance to drying (dessication);
Resistance to low levels of disinfection, e.g. as in potable water supplies;
Cyst wall contains cellulose/chitin and stains well with calcofluor white
In which of the following, previously thought not to have a cyst stage, has a cyst stage
recently been described. - answersDientamoeba fragilis
Trophozoites of intestinal protozoa are more likely than the cyst stages to be present in
a stool
specimen that was Bristol Stool Scale Type 1 - answersFalse
Intermittent "showering" of organisms on feces may occur with many of the intestinal
protozoa, but is frequently encountered with - answersGiardia lamblia
Which of the following is easily cultured on a non-nutrient agar medium with Escherichia
coli - answersAcanthamoeba species
With which of the following is the cyst stage resistant to adverse conditions in the
environment, eg. drying, potable levels of chlorine in waters - answersEntamoeba
histolytica/dispar;
Giardia lamblia
What features of an amebal nucleus may be determined in a trichrome-stained smear
but not in an unstained wet preparation. - answersSize and position of the karyosome;
Peripheral chromatin
For the lab. diagnosis of trichomoniasis, which of the following is the correct order for
sensitivity - answersCulture > Acridine orange stained smear > Wet preparation
Trichomonas infection in females is known to be associated with - answersPremature
labor and delivery;
Increased risk factor in acquisition of HIV;
Infections in the neonate
Trichomoniasis is a nationally reportable disease in the USA - answersFalse
A recent study (J. Clin. Microbiol 2012;50:2601-2606) of >7,000 urogenital tract
specimens from women and ordered by the ordering physician only for testing for
If a parasite has a sexual stage, the host in which that stage occurs is known as the -
answersDefinitive host
If an infected host is described as a "dead end" host, it means - answersThe parasite
cannot complete its life cycle in that host
The value of using polyvinyl alcohol (PVA) as a stool fixative is that - answersSmears
for a "permanent stain", eg trichrome, can be made from it
In the formalin-ethyl acetate procedure concentration procedure, parasitic structures are
expected to be present in which of the four layers after centrifugation -
answersSediment
In the parts of the US with temperate climate, the most frequently encountered enteric
parasites are... - answersCryptosporidium and Giardia
In a hospital setting, a specimen of unformed feces is brought to the lab. immediately
after collection; you know that it cannot be examined immediately, so you would... -
answersMix a sample of it into 10% formalin and a sample into polyvinyl alcohol (PVA)
An outpatient comes to the laboratory with a physician's orders for "O & P x3" No
instructions have been given to the patient other than to get collection kits from the lab.
You give the patient collection kits and advise the patient to... - answersCollect 3
specimens 2 days apart, say Monday, Wednesday, and Friday
With the increasing use of immunoassays in parasitology, of concern is/are -
answersThe compatibility of the fixative(s) used to preserve the fecal specimen
The possibility of "missing" (not detecting) parasites other than those detected by the
immunoassay
"Non-traditional" parasitology stain(s) that now have an important role in parasitology
microscopy include - answersCalcofluor white stain; Modified (reduced decolorization)
acid-fast stain; and Acridine orange stain
What type of infections may be caused by all 3 of the genera of free-living amebae,
Naegleria, Acanthamoeba, and Balamuthia - answersCentral nervous system (CNS)
infections
, In which of the free-living ameba genera is there a flagellate stage - answersNaegleria
Cysts of the free-living amebae typically have which of the following properties -
answersResistance to drying (dessication);
Resistance to low levels of disinfection, e.g. as in potable water supplies;
Cyst wall contains cellulose/chitin and stains well with calcofluor white
In which of the following, previously thought not to have a cyst stage, has a cyst stage
recently been described. - answersDientamoeba fragilis
Trophozoites of intestinal protozoa are more likely than the cyst stages to be present in
a stool
specimen that was Bristol Stool Scale Type 1 - answersFalse
Intermittent "showering" of organisms on feces may occur with many of the intestinal
protozoa, but is frequently encountered with - answersGiardia lamblia
Which of the following is easily cultured on a non-nutrient agar medium with Escherichia
coli - answersAcanthamoeba species
With which of the following is the cyst stage resistant to adverse conditions in the
environment, eg. drying, potable levels of chlorine in waters - answersEntamoeba
histolytica/dispar;
Giardia lamblia
What features of an amebal nucleus may be determined in a trichrome-stained smear
but not in an unstained wet preparation. - answersSize and position of the karyosome;
Peripheral chromatin
For the lab. diagnosis of trichomoniasis, which of the following is the correct order for
sensitivity - answersCulture > Acridine orange stained smear > Wet preparation
Trichomonas infection in females is known to be associated with - answersPremature
labor and delivery;
Increased risk factor in acquisition of HIV;
Infections in the neonate
Trichomoniasis is a nationally reportable disease in the USA - answersFalse
A recent study (J. Clin. Microbiol 2012;50:2601-2606) of >7,000 urogenital tract
specimens from women and ordered by the ordering physician only for testing for
