Deck 65: Antiviral Therapy Susceptibility Testing and Prevention

Question 1

Point mutations in the hemagglutination (HA)or neuraminidase (NA)genes during viral ribonucleoprotein (RNP)replication give rise to new strains.This mechanism is known as the antigenic:

A)drift.
B)shift.
C)re-assortment.
D)modification.

Answer 1

A
The antigenic drift is caused by sequential point mutations in the HA or NA genes that occur during viral RNP replication and immune selection,which give rise to new strains;thus,the antigenic drift gives the virus the ability to re-infect nonimmune susceptible hosts each season.Another phenomenon is the antigenic shift.Influenza A solely possesses this mechanism;it involves the complete re-assortment of the segmented viral genome during a co-infection with a nonhuman animal,which results in major antigenic change and periodic worldwide outbreaks (pandemics)of a never-before-circulated type of influenza A virus.Influenza B undergoes antigenic change very slowly.

Question 2

Match the virus with the appropriate antiviral agent.
a.HSV
b.Influenza A
c.Hepatitis B virus (HBV)
d.Respiratory syncytial virus (RSV)
e.HIV
Ribavirin

Answer 2

D

Question 3

If a physician prescribes Tamiflu to a patient,the patient is most likely infected with which virus?

A)HIV
B)Herpes simplex virus (HSV)
C)Cytomegalovirus (CMV)
D)Influenza

Answer 3

D
NA inhibitors include the medications zanamivir (Relenza)and oseltamivir (Tamiflu).Both drugs inhibit the viral protein,NA,which prevents the virus release from infected cells.The NA inhibitors are used to treat both influenza A and influenza B,although lower efficacy against influenza B has been reported when using oseltamivir.All classes of drugs are most effective when administrated within 48 hours of the onset of symptoms and work to shorten the duration of the infection,as well as reduce complications.

Question 4

Match the virus with the appropriate antiviral agent.
a.HSV
b.Influenza A
c.Hepatitis B virus (HBV)
d.Respiratory syncytial virus (RSV)
e.HIV
Emtricitabine

Question 5

MATCHING
Match the assay with its function.
a.Phenotypic assay
b.Plaque reduction assay
c.Du assay
d.Flow cytometry
e.Genotypic susceptibility assay
f.Pyrosequencing
Inhibits viral plaque formation.

Question 6

The only virus that has been globally eradicated is:

A)chicken pox.
B)cowpox.
C)smallpox.
D)swinepox.

Question 7

Match the virus with the appropriate antiviral agent.
a.HSV
b.Influenza A
c.Hepatitis B virus (HBV)
d.Respiratory syncytial virus (RSV)
e.HIV
Acyclovir

Question 8

At the end of the 2008-2009 influenza season,100% of influenza A H3N2 and the novel 2009 influenza A H1N1 were resistant to:

A)adamantane.
B)oseltamivir.
C)Tamiflu.
D)Relenza.

Question 9

MATCHING
Match the assay with its function.
a.Phenotypic assay
b.Plaque reduction assay
c.Du assay
d.Flow cytometry
e.Genotypic susceptibility assay
f.Pyrosequencing
Viable cells take up neutral red dye.

Question 10

Match the virus with the appropriate antiviral agent.
a.HSV
b.Influenza A
c.Hepatitis B virus (HBV)
d.Respiratory syncytial virus (RSV)
e.HIV
Lamivudine

Question 11

Match the virus with the appropriate antiviral agent.
a.HSV
b.Influenza A
c.Hepatitis B virus (HBV)
d.Respiratory syncytial virus (RSV)
e.HIV
Amantadine

Question 12

When performing antiviral susceptibility testing,a standard inoculum must be used.If the inoculum quantity is too large,then the isolate will appear:

A)susceptible.
B)intermediate.
C)resistant.
D)indeterminate.

Question 13

MATCHING
Match the assay with its function.
a.Phenotypic assay
b.Plaque reduction assay
c.Du assay
d.Flow cytometry
e.Genotypic susceptibility assay
f.Pyrosequencing
Detects resistance genes.

Question 14

MATCHING
Match the assay with its function.
a.Phenotypic assay
b.Plaque reduction assay
c.Du assay
d.Flow cytometry
e.Genotypic susceptibility assay
f.Pyrosequencing
Quantifies sequence variation.

Question 15

MATCHING
Match the assay with its function.
a.Phenotypic assay
b.Plaque reduction assay
c.Du assay
d.Flow cytometry
e.Genotypic susceptibility assay
f.Pyrosequencing
Inhibits viral DNA synthesis.

Question 16

Which type of assay uses a variety of endpoint measurements to determine whether the virus is inhibited by the antiviral drug or is demonstrating drug resistance?

A)Phenotypic
B)Genotypic
C)NA inhibition assay
D)Enzyme immunoassay

Question 17

The recombinant virus assay (RVA)uses which type of amplification methodology?

A)Transcription-mediated amplification (TMA)
B)Nucleic acid sequence-based amplification (NASBA)
C)Strand displacement amplification (SDA)
D)Reverse transcription polymerase chain reaction (RT-PCR)

Question 18

MATCHING
Match the assay with its function.
a.Phenotypic assay
b.Plaque reduction assay
c.Du assay
d.Flow cytometry
e.Genotypic susceptibility assay
f.Pyrosequencing
Quantifies the amount of viruses infected in cells.