3-How Viruses Become Diverse and Diagnostic Virology

Question 1

Viral genetics resulting in large changes?

Answer 1

Genetic Shift

Question 2

Two viruses of the same type infect the same cell; they might switch parts of their genome, resulting in several proteins being switched at a time between the strains.

Answer 2

Gene Recombination

Question 3

Happens when two strains of the same segmented virus infect the same cell, the resulting viruses have segments from both viruses resulting in a very different virus from the parental strains.

Answer 3

Gene Reassortment

Question 4

Gene Reassortment needs a segmented genome and is most important with … and …

Answer 4

influenza (responsible for the major influenza pandemics) and reovirus

Question 5

Viral genetics resulting in mutations - small changes?

Answer 5

Genetic Drift

Question 6

What means how many mistakes they make?

Answer 6

fidelity

Question 7

What has the highest polymerase fidelity; mutation rate?

Answer 7

RNA viruses - lack ability to proof read

RNA viruses > DNA viruses > Prokaryotes > Eukaryotes

Question 8

What in cytology is used to detect HSV or VZV from lesions?

Answer 8

Tzanck smear

Question 9

What is used to test for viral antigens or antibodies?

Answer 9

ELISA or EIA (enzyme-linked immunosorbent assay)

Question 10

What does ELISA detect for an acute infection?

Answer 10

IgM

Question 11

What does ELISA detect for a chronic infection?

Answer 11

IgG

Question 12

What test is specific for 1 virus and can also be used to check for vaccine efficacy?

Answer 12

ELISA or EIA

Question 13

What is a quick easy test, checking for the presence of viral antigens or viral antibodies?

Answer 13

Lateral Flow Assay

Question 14

If the virus undergoes … the ELISA and Lateral Flow Assays might not pick up the new strain?

Answer 14

Antigen drift (mutation)

Question 15

Influenza rapid tests have 50-70% … = proportion of true positives identified.

Answer 15

Sensitivity

Question 16

Influenza rapid tests have a 90-95% … = proportion of true negatives identified.

Answer 16

Specificity

Question 17

What test is very sensitive, usually picks up an infection if it is present; can test for several infections at once but very expensive and not done unless the person is very sick?

Answer 17

Nucleic Acid Amplification Test