Diagnosis of Viral infections 3

Question 1

_________ is a diagnostic tool that amplifies viral genome/DNA

Answer 1

PCR

Question 2

How does PCR work?

Answer 2

1. Denaturation
2. Annealing
3. Extension/Elongation

Question 3

What is genome sequencing?

Answer 3

when the sequence of bases in a DNA molecule is elucidated/ can be obtained and read

Question 4

Why is genome sequencing important?

Answer 4

1. Detects pathogens
2. Studies genetic variation, genotyping, evolution, and interspecies transmission of pathogens
3. ID undiscovered strains
4. Development diagnostics
5. ID genes associated with drug resistance
6. Develop therapeutics
7. Judge efficacy of vaccines

Question 5

What is phylogenetic analysis?

Answer 5

using viral genome sequence data to study evolution of viruses and genetic relationships among viruses

Question 6

In competitive ELISA, a ______ in signal when compared to assay wells with purified antigen alone indicates the presence of antigens in the sample/ a positive result

Answer 6

decrease

Question 7

In competitive ELISA, what indicates the presence of antigens in the sample (positive result)?

Answer 7

Weak signal or decrease in signal = positive result

Question 8

_____ is when labeled Ab are added onto a sample Ag and visible fluorescence appears at the binding sites of the specific Ab

Answer 8

Direct fluorescence Antibody test

Question 9

_______ is when a secondary antibody labeled with fluorescent marker recognizes the primary Ab bound to Ag

Answer 9

Indirect fluorescence antibody test

Question 10

How does immunohistochemistry work?

Answer 10

Applied directly on tissue

Ab tagged with enzyme, enzyme reacts w substrate to produce color change that can be seen on standard light microscope

Question 11

What is immunochromatography?

Answer 11

• Lateral flow device
• A form of POC (point of care) test that is simple to perform, easy to carry, and does not require specialized equipment

Ex: pregnancy test

Question 12

What happens in agglutination?

Answer 12

Uses specific antibodies to bind many antigens into single clumps to find large complexes which are easily precipitated and can be seen macroscopically or microscopically

Question 13

What is agar gel immunodiffusion test?

Answer 13

Antigen and antibody in separate wells on an agar gel

Ag and Ab diffuse towards eachother

Thin white line is formed due to precipitation of Ag-Ab complex

Question 14

How does complement fixation test result in a positive reaction?

Answer 14

If serum has antibodies against virus A, intact sheep RBCs will settle at the bottom

Question 15

How does a complement fixation test result in a negative reaction?

Answer 15

If serum is negative for a virus and has no antibodies, there will be hemolysis and destruction of sheep RBCs

Question 16

What are advantages of using next generation sequencing?

Answer 16

Cheaper, quicker, requires less DNA, and is more accurate and reliable than Sanger sequencing

Question 17

What is metagenomics?

Answer 17

when a samples entire nucleotide sequence in analyzed by amplification and sequences of the whole genome

Powerful method for random detection of existing and new pathogens

Question 18

__________ uses viral genome sequence data to study evolution of viruses and genetic relationships among viruses

Answer 18

Phylogenic analysis

Question 19

What is a microarray?

Answer 19

When thousands of known DNAs are amplified by PCRs and spotted onto a glass or silicon strip

Question 20

What does a positive microarray result look like?

Answer 20

Generates a fluorescent signal from the spot where the probe DNA is spotted in the chip

Question 21

What is the advantage of using a microarray?

Answer 21

Hundreds of pathogens can be screened simultaneously using a single microarray chip

Question 22

The study of virus evolution using genome sequence data is known as __________

Answer 22

Phylogenetics

Question 23

_________ is a form of POC test

Answer 23

Immunochromatography

Question 24

_________ is a method that uses bead like clumping of Antibodies

Answer 24

Agglutination

Question 25

A positive sample using complement fixation would reveal ________

Answer 25

RBCs settled on the bottom