Question 1

MATCHING
Match the assay with its function.
-Quantifies the amount of viruses infected in cells.

Accepted Answer

D

Question 2

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

Accepted Answer

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 3

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?

Accepted Answer

Phenotypic assays use a variety of endpoint measurements to determine whether the virus is inhibited by the antiviral drug or is demonstrating drug resistance.Some of these endpoint measurements include a reduction in the number of plaques, an inhibition of viral deoxyribonucleic acid (DNA)synthesis, a reduction in the yield of a viral structural protein, and a reduction of the enzymatic activity of a functional protein.

Question 4

The only virus that has been globally eradicated is:

Accepted Answer

Global eradication of a viral disease has only occurred with smallpox.The eradication of any viral disease requires no animal reservoir, a lack of recurrent infectivity, one or few stable serotypes, and an effective vaccine.

Question 5

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

Accepted Answer

The final result of antiviral susceptibility testing is determined by many variables; these variables also act to hinder the standardization of antiviral susceptibility testing.Some of these variables include: (1)cell line used to grow the virus, (2)viral inoculum titer, (3)incubation time of the culture, (4)concentration range of the antiviral tested, (5)reference strains, (6)assay method, (7)endpoint criteria, (8)calculation of the endpoint, and (9)interpretation of the endpoint.Each of these factors has variables that affect the final results.For example, if the inoculum quantity is too large, then a susceptible isolate may appear resistant; if the inoculum quantity is too small, then the isolate may appear susceptible.Because of each of these variables, establishing control strains to also be tested when performing antiviral susceptibility testing is imperative.

Question 6

Match the virus with the appropriate antiviral agent.
-Ribavirin

Accepted Answer

Ribavirin is used for treatment of RSV infections in both adults and children. It is not effective for the other viruses listed.

Question 7

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:

Accepted Answer

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 8

Match the virus with the appropriate antiviral agent.
-Lamivudine

Accepted Answer

Lamivudine is an antiviral agent used to treat HBV infections by interfering with reverse transcriptase, the enzyme that allows the virus to replicate.

Answer: E
 Lamivudine is also effective against HIV and is included in many antiretroviral regimens to treat and prevent the virus.

Note: Lamivudine is not effective against HSV, Influenza A or RSV.

Question 9

MATCHING
Match the assay with its function.
-Detects resistance genes.

Accepted Answer

Genotypic susceptibility assay is specifically designed to detect resistance genes.

Question 10

Match the virus with the appropriate antiviral agent.
-Saquinavir

Accepted Answer

Saquinavir is a protease inhibitor used in the treatment of HIV.

Question 11

MATCHING
Match the assay with its function.
-Inhibits viral plaque formation.

Accepted Answer

Plaque reduction assay is designed to test the antiviral activity of a compound by measuring reduction in virus-induced plaques. It inhibits viral plaque formation.

Answer: E
 Genotypic susceptibility assay is used to determine which drugs will be most effective against a particular virus, based on its genetic makeup. It does not have a function related to inhibiting viral plaque formation.

Answer: F
 Pyrosequencing is a method of DNA sequencing, used to analyze the sequence of nucleotides in a sample. It does not have a function related to inhibiting viral plaque formation.

Answer: A, D, C
 Phenotypic assay is an assay that detects a specific phenotype or observable characteristic. Flow cytometry is a technique used to analyze the physical and chemical properties of cells. Du assay is an assay used to measure the immune response of an individual to a vaccine. None of these assays have a function related to inhibiting viral plaque formation.

Question 12

Match the virus with the appropriate antiviral agent.
-Amantadine

Accepted Answer

Amantadine is an antiviral agent that is effective against Influenza A virus. It inhibits the replication of the virus. It is not effective against other viruses listed.

Question 13

MATCHING
Match the assay with its function.
-Quantifies sequence variation.

Accepted Answer

The answer of MATCHING
Match the assay with its function.
-Quantifies sequence...

Question 14

MATCHING
Match the assay with its function.
-Viable cells take up neutral red dye.

Accepted Answer

The answer of MATCHING
Match the assay with its function.
-Viable cells...

Question 15

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

Accepted Answer

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

Question 16

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

Accepted Answer

A phenotypic type of susceptibility testing for human immunodeficiency virus (HIV)is the RVA.This assay is used to test HIV-1 isolates to nucleoside analog reverse transcriptase (RT)inhibitors.RVA uses RT-PCR amplification of RT and protease (PR)gene coding sequences directly from the patient's plasma.

Question 17

Match the virus with the appropriate antiviral agent.
-Acyclovir

Accepted Answer

Acyclovir is effective against HSV and is commonly used to treat HSV infections, including genital herpes and cold sores.

Answer: B) None 
 Acyclovir is not effective against influenza A. Antiviral agents that are effective against influenza A include oseltamivir (Tamiflu) and zanamivir (Relenza).

Answer: C) None 
 Acyclovir is not effective against HBV. Antiviral agents that are effective against HBV include entecavir (Baraclude) and tenofovir (Viread).

Answer: D) None 
 Acyclovir is not effective against RSV. Antiviral agents that are effective against RSV include ribavirin (Virazole) and palivizumab (Synagis).

Answer: E) None 
 While acyclovir may be effective against some herpes viruses that are related to HIV, it is not effective against HIV itself. Antiretroviral drugs are used to treat HIV infections.

Question 18

In the 1920s, an instrument known as an "iron lung" was developed to fight breathing difficulties associated with which infection?

Accepted Answer

In the late 1920s, an instrument known as the "iron lung" was developed and used to fight the breathing difficulties associated with acute flaccid paralysis-poliomyelitis.This tank respirator provided a chamber that encased the patient in an air-tight chamber and created a negative pressure around the patient's thoracic cavity, causing air to rush into the lungs to facilitate breathing.Because of the poliomyelitis epidemics in the 1930s through the 1950s, entire polio wards that housed these "iron lungs" were established in hospitals and used to provide respiration for patients who were the most severely affected.

Question 19

MATCHING
Match the assay with its function.
-Inhibits viral DNA synthesis.

Accepted Answer

The answer of MATCHING
Match the assay with its function.
-Inhibits viral...

Quiz 66: Antiviral Therapy, Susceptibility Testing, and Prevention

MATCHING Match the assay with its function. -Quantifies the amount of viruses infected in cells.

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

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?

The only virus that has been globally eradicated is:

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

Match the virus with the appropriate antiviral agent. -Ribavirin

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:

Match the virus with the appropriate antiviral agent. -Lamivudine

MATCHING Match the assay with its function. -Detects resistance genes.

Match the virus with the appropriate antiviral agent. -Saquinavir

MATCHING Match the assay with its function. -Inhibits viral plaque formation.

Match the virus with the appropriate antiviral agent. -Amantadine

MATCHING Match the assay with its function. -Quantifies sequence variation.

MATCHING Match the assay with its function. -Viable cells take up neutral red dye.

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

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

Match the virus with the appropriate antiviral agent. -Acyclovir

In the 1920s, an instrument known as an "iron lung" was developed to fight breathing difficulties associated with which infection?

MATCHING Match the assay with its function. -Inhibits viral DNA synthesis.