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:
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:
Cellophane tape test
Female pinworms do not release their eggs inside the host's intestine, so eggs are
not found in feces. The cellophane tape test is used to recover eggs found around
the anus after migrating females leave the lower intestine and die outside the
host.✔✔The best method to recover pinworm eggs is the:
Operculated eggs
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:
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:
Cellophane tape test
Female pinworms do not release their eggs inside the host's intestine, so eggs are
not found in feces. The cellophane tape test is used to recover eggs found around
the anus after migrating females leave the lower intestine and die outside the
host.✔✔The best method to recover pinworm eggs is the:
Operculated eggs
