Parasitology Chapter 10 Questions And
Answers
Giardia lamblia
G.lamblia adheres to the intestinal mucosa and appears intermittently in feces; therefore, three to
six samples may be needed to successfully find the organisms. For which of the following
parasites might the examination of as many as six specimens be needed in order to recover the
parasite:
Castor oil If patients must be purged to enhance recovery of parasites, any of the
following enemics may be used EXCEPT:
PVA (polyvinyl-alcohol)
PVA provides the best adhesion properties of the various preservatives listed. The
chemical found in fecal preservatives that enhance adhesion of parasites to slides prepared for
trichrome stain is:
Eosinophils
Charcot-Leyden crystals are thought to be disintegrating eosinophilic granules. Charcot-
Leydin crystals are occasionally observed in stool. These crystals are probably from breakdown
products of:
, Parasitology Chapter 10 Questions And
Answers
Non-nutrient agar plate seeded with E. coli bacteria
A non-nutrient agar plate seeded (inoculated) with E. coli bacteria is inoculated with a patient
sample or a possibly infected eye care solution to detect the presence of ameba. If Acanthamoeba
are present, they will feed on the bacteria and propagate, leading to increased numbers of ameba,
which can be observed directly on the plate when it is examined using a microscope. The
most sensitive method used to recover Acanthamoeba spp. from eye-care solutions or corneal
samples is the:
The decolorizer is weaker and you do not need to use heat
A weaker decolorizer is needed because parasitic cells do not bind the dye as tightly as AFB
cells. Modified acid-fast stain is used to visualize several parasites including
Cryptosporidium parvum. The modification that differentiates this method from that used to stain
mycobacteria (AFB) is that in the parasite method:
Pollen grains
Pollen grains commonly appear similar to eggs or cysts. An artifact found in feces that
can be confused with eggs or cysts is/are:
Answers
Giardia lamblia
G.lamblia adheres to the intestinal mucosa and appears intermittently in feces; therefore, three to
six samples may be needed to successfully find the organisms. For which of the following
parasites might the examination of as many as six specimens be needed in order to recover the
parasite:
Castor oil If patients must be purged to enhance recovery of parasites, any of the
following enemics may be used EXCEPT:
PVA (polyvinyl-alcohol)
PVA provides the best adhesion properties of the various preservatives listed. The
chemical found in fecal preservatives that enhance adhesion of parasites to slides prepared for
trichrome stain is:
Eosinophils
Charcot-Leyden crystals are thought to be disintegrating eosinophilic granules. Charcot-
Leydin crystals are occasionally observed in stool. These crystals are probably from breakdown
products of:
, Parasitology Chapter 10 Questions And
Answers
Non-nutrient agar plate seeded with E. coli bacteria
A non-nutrient agar plate seeded (inoculated) with E. coli bacteria is inoculated with a patient
sample or a possibly infected eye care solution to detect the presence of ameba. If Acanthamoeba
are present, they will feed on the bacteria and propagate, leading to increased numbers of ameba,
which can be observed directly on the plate when it is examined using a microscope. The
most sensitive method used to recover Acanthamoeba spp. from eye-care solutions or corneal
samples is the:
The decolorizer is weaker and you do not need to use heat
A weaker decolorizer is needed because parasitic cells do not bind the dye as tightly as AFB
cells. Modified acid-fast stain is used to visualize several parasites including
Cryptosporidium parvum. The modification that differentiates this method from that used to stain
mycobacteria (AFB) is that in the parasite method:
Pollen grains
Pollen grains commonly appear similar to eggs or cysts. An artifact found in feces that
can be confused with eggs or cysts is/are:
