Parasitology- Exam review- Exam I Questions And
Answers
If a parasite has a sexual stage, the host in which that stage occurs is known as
the
Definitive host
If an infected host is described as a "dead end" host, it means
The parasite cannot complete its life cycle in that host
The value of using polyvinyl alcohol (PVA) as a stool fixative is that
Smears 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
Sediment
In the parts of the US with temperate climate, the most frequently encountered
enteric parasites are...
Cryptosporidium 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...
Mix 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...
Collect 3 specimens 2 days apart, say Monday, Wednesday, and Friday
With the increasing use of immunoassays in parasitology, of concern is/are
The 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
Calcofluor 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
Central nervous system (CNS) infections
In which of the free-living ameba genera is there a flagellate stage
Naegleria
Cysts of the free-living amebae typically have which of the following properties
Resistance 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.
Dientamoeba 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
False
Intermittent "showering" of organisms on feces may occur with many of the
intestinal protozoa, but is frequently encountered with
Giardia lamblia
Which of the following is easily cultured on a non-nutrient agar medium with
Escherichia coli
Acanthamoeba 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
Answers
If a parasite has a sexual stage, the host in which that stage occurs is known as
the
Definitive host
If an infected host is described as a "dead end" host, it means
The parasite cannot complete its life cycle in that host
The value of using polyvinyl alcohol (PVA) as a stool fixative is that
Smears 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
Sediment
In the parts of the US with temperate climate, the most frequently encountered
enteric parasites are...
Cryptosporidium 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...
Mix 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...
Collect 3 specimens 2 days apart, say Monday, Wednesday, and Friday
With the increasing use of immunoassays in parasitology, of concern is/are
The 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
Calcofluor 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
Central nervous system (CNS) infections
In which of the free-living ameba genera is there a flagellate stage
Naegleria
Cysts of the free-living amebae typically have which of the following properties
Resistance 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.
Dientamoeba 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
False
Intermittent "showering" of organisms on feces may occur with many of the
intestinal protozoa, but is frequently encountered with
Giardia lamblia
Which of the following is easily cultured on a non-nutrient agar medium with
Escherichia coli
Acanthamoeba 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
