Diagnostic Virology Flashcards
Which is false?
A. Most viral infections are self-limiting and asymptomatic
B. Non-specific symptoms of viral diseases like fever can be
due to a number of viral agents
C. A particular virus can produce a number of signs and
symptoms
D. Antiviral drugs are ubiquitous
D
In diagnostic virology, turn around time for most laboratory methods is not timely enough. T or F?
T
In specimen collection, handling and transport, what are the three As one must consider?
Appropriateness of specimen
Adequacy of specimen
Adherence to universal precautions
Diff viruses, diff ideal specimens. Which is false?
A. for respiratory diseases: nasopharyngeal aspirates
are the best specimens
B. for systemic diseases: blood
C. for HSV1 (singaw): swab only
D. none of the above
C
For HSV1: swab for microscopy and rapid
diagnosis, obtained from the base of lesion; aspirate
for acute infection with vesicular lesion
Which virus has diagnosis process where the specimen better obtained in convalescent phase?
SARS coronavirus
In which two stages of disease is virus frequently detectable in test materials?
onset & acute phase
In which three stages of the disease is specific antibody demonstrable?
acute phase, recovery and convalescence
Which is false?
A)If viral specimen cannot be transported immediately, store at -70 deg C or liquid nitrogen temperature (-180 deg
C)
B) Do not freeze specimens
C) Generally, all solid specimens except blood are transported in viral transport medium
D) none of the above
C
stool dapat
What three things must be present in virus transport media?
antibiotics, buffered salt solution and proteinaceous substance
method which would involve antigen-antbody interactions
serology
One of the methods of antigen detection is direct examination. What is done here?
use of whole or parts of virion
All are direct exam methods for antigen detection except?
a. light and electron microscopy
b. cell culture
c. viral genome detection
B
Which is not a classical technique of antigen detection? A. Western blot B. Neutralization C. Counter-immunoelectrophoresis D. Complement fixation
A
Which is not a newer technique of antigen detection? A. Western blot B. Particle agglutination C. Counter-immunoelectrophoresis D. Radioimunoassay
C
Which is not a classical technique of antigen detection? A. Immunofluorescence B. RIBA C. Counter-immunoelectrophoresis D. Complement fixation
B
Which is not a newer technique of antigen detection? A. Line immunoassay B. RIBA C. Enzyme linked immunoassay D. Hemagglutination inhibition
D
How is a virus sample decontaminated? (3 steps.)
centrifugation
filtration
antibiotic usage
When Shaula isolated a certain virus, she noticed that there was a change in color, from pink to yellow. What does this mean?
There was an exchange of gases, signifying metabolism.
Which is false?
A. All viruses are culturable
B. From isolates, you may know the sequence and
pathogenesis of the virus.
C. Cells should generally be liquid in form for inoculation in
37 deg C, with 5% CO2.
A.All viruses are culturable
(not all! i.e. Hepatitis virus: use of
molecular techniques)
Which is false?
A. Plates are used for diagnosis
B. Flasks are used for propagation of cells
C. The worst cells are the newly propagated ones.
C
best sila
Which is not a purpose of animal inoculation?
A. To produce viruses which cannot be propagated in vivo
B. To study the pathogenesis of virus infections, e.g.
coxsackie viruses
C. To test vaccine safety
D. None of the above
A
in vitro dapat yan
Identify the cell in culture
o Cells are bipolar or multipolar
o Elongated shapes
o Grow attached to a substrate
fibroblastic
identify the cell in culture
o Polygonal in shape with more regular dimensions
o Grow attached to a substrate in discrete patches
epithelial-like
identify the cell in culture
o Cells are spherical in shape
o Usually grown in suspension without attaching to a
surface
lymphoblast-like
False about primary culture of cells A.Directly from parent tissue B.Have the same karyotype and chromosome number as the original tissue C.Long life span
C.
Short dapat
False about diploid cell line
A. from continuous cell line
B. at least 75% of the cells have the same karyotype as
the cells of the original tissue
C. can survive for about 20-50 subcultures
A
continuous cell line ang galing sa diploid cell line
False about continuous cell line
A. from diploid cell line
B. at least 75% of the cells have the same karyotype as
the cells of the original tissue
C. can survive for about 20-50 subcultures
D. from benign tissue
D
malignant dapat
Which is false?
A.Primary culture involves cells from the liver
B.Primary culture involves fibroblast-like or
epithelial-like
C.Influenza virus is cultured in primary culture
A
kidney dapat
Which is false?
A. In continuous cell lines, Herpes Simplex virus and Varicella Zoster virus can be cultured.
B. Diploid cell lines are fibroblast in nature.
C. none of the above
A
diploid dapat
diploid cell line: __ from human kidney or
lung fibroblasts
WI-38 and MRC-5
continuous cell line: identify two types
HeLa (from human cervical carcinoma),
Vero (African green monkey kidney)
Which does not have (+) growth in fibroblasts, A549 and RhMK cells? A. Adenoviruses B. CMV C. HSV D. none of the 3
B
A.Hemadsoprtion is dependent upon selective attachment of leukocytes onto the monolayer surface of tissue culture cells.
B.It is perfomed on CPE negative cultures.
Which is false?
A
erythrocytes dapat
What viral diagnostic method is this?
demonstrated by addition of erythrocytes to a tissue
culture system in which propagation of a hemagglutinin-producing virus has occurred
hemadsorption
What viral diagnostic method is this?
• It uses a smaller tube containing a coverslip and it is
actually the coverslip that contains the cell monolayer
shell vial technique
Sequence the steps for shell vial technique
A. the tube undergoes centrifugatiofollowed by a short incubation time
B. the coverslip is removed and stained with specific
monoclonal antibodies for a certain virus
C. the cell layer inoculated with specimen
C A B
Identify the histopathology manifestation
- -> nuclear or cytoplasmic aggregates of stainable substances, usually proteins
- -> typically represent sites of viral multiplication in a bacterium or a eukaryotic cell
- -> usually consist of viral capsid proteins
inclusion bodies
Which is false?
A.The shell vials are usually set up so
that only 1 virus can be identified per tube.
B.Immuno-EM decreases sensitivity.
B
increase dapat
Differentiate Southern from Northern Blot.
genome involved
Southern: DNA
Northern: RNA
Identify the viral genome detection method
a mixture containing the molecule to be
detected is applied directly on a membrane as a dot. This is
then followed by detection by either nucleotide probes or
antibodies
Dot-blot
What happens in in situ hybridization?
uses a labeled complementary
DNA or RNA strand (i.e., probe) to localize a specific DNA
or RNA sequence in a portion or section of tissue
False about PCR
a. Extremely liable to contamination
b. High degree of operator skill required
c. Not easy to set up a qualititative assay
d. A positive result may be difficult to interpret,
c
quantitative yan dapat
PCR can be applied also in RNA viruses by adding__
reverse transcriptase
differentiate cross contam from carry-over contam
cross contam: contam c/o non-amplified matl from envt
carry over contam: contam c/o amplicons from earlier PCRs
Ethidium bromide dye fluoresces under UV illumination to reveal the locations of DNA within a gel.
this is an example of __
gel electrophoresis
In serology, what is the main diff bet primary infection and reinfection?
IgM is present in primary infection only
True or False
Amount of color produced is directly proportional
to amount of antibody in the test specimen
False
inversely dapat
Differentiate direct fr indirect immunofluorescence
direct: Antibody specific to the antigen is directly tagged with the fluorochrome
indirect: Antibody specific for the antigen is unlabeled and a second anti-Ig antibody directed toward the first antibody
is tagged with the fluorochrome
identify
Produce ample green fluorescence
o Immunofluorescent microscope needed to see stain
fluoroisothiocyanate
Produce red color
o No need for IF microscope
identify
rhodamine
best specimen for RSV Influenza A & B Parainfluenza Adenovirus
nasopharyngeal aspirate
best specimen for
Rotaviruses
Adenoviruses
Astrovirus
feces
skin is best specimen for which viruses?
HSV
VZV
specific test for CMV, involves blood
pp65 antigenaemia test
False about radiommunoassay
A.Radioactive versions of a substance (isotopes of the
substance) are mixed with antibodies and inserted in a
sample of the patient’s urine.
B.The same non-radioactive substance in the blood takes the place of the isotope in the antibodies, thus leaving the
radioactive substance free.
C.The radioactivity of each bound antigen is measured with a scintillation counter.
A
blood. not urine
identify the viral diagnostic method
• Based on the electrophoretic separation of the crude
antigen and transfer of the separated fractions to a
nitrocellulose sheet in which they are immobilized
immunoblotting
rely on the consumption of the complement by the Ag/Ab complex
complement fixation
What produces a positive result in complement fixation?
presence of Ag-Ab complex and absence of lysis
Complement fixation is not done anymore, T or F?
T
Identify the diagnostic test
Based on the ability of specific antibodies to interfere with
some biologic function of the virus
• The infective property of the virus is blocked
neutralization
positive result for neutralization
absence of CPE
Measures the ability of soluble antigen to inhibit the
agglutination of antigen-coated red blood cells by
antibodies
hemagglutination inhibition
for these viruses, the onset of clinical symptoms coincide with the development of antibodies A. rubella and Hep A B. respiratory and enteric viruses C. HIV and rabies
A
Many viruses often produce clinical disease before the appearance of antibodies such as A. rubella and Hep A B. respiratory and enteric viruses C. HIV and rabies
B
• There are also viruses which produce clinical disease
months or years after seroconversion as seen in
A. rubella and Hep A
B. respiratory and enteric viruses
C. HIV and rabies
C
