Virology

Question 1

Name different methods of viral diagnosis

Answer 1

Detecting viral genome PCR
Detecting viral antigen IFA, ELISA
Detecting virus particles EM, HA
Detecting virus cytopathic effect in cultured cells (Virus isolation)

Detecting antibodies to virus (serology)

Question 2

How can we manipulate/generate viruses?

Answer 2

Virus genomes are so small they can be synthesised.
The viral DNA/RNA is introduced into cells.
Cell thinks it’s been infected by virus itself, therefore starts to make viral particles using the viral DNA
We can introduce mutations to engineer the viruses to our advantage eg if want to use them to make vaccinesThis allows reverse genetics, the creation of viruses at will with engineered mutations in their genomes.

Question 3

3. A bronchial lavage has been provided from a patient suspected of infection with the novel coronavirus, SARS CoV2. Which test is most likely to be used to confirm the aetiologic agent?

Answer 3

RT-PCR

because it has RNA so need reverse transcriptase to change to DNA

Question 4

What is the cytopathic effect?

Answer 4

death of cell caused by a virus - virus shuts down cell and takes cell machinery for its own manipulation. Cell triggers apoptosis as a result and then lyses. Cytopathic effect is usually a result of the virus lysing the cell.
This could be due to shut down of host protein synthesis or accumulation of viral proteins

Question 5

What are the two presentations a virus can create on a cell culture, that we can use to quantify the number of virus particles in a sample?

Answer 5

Viral Plaques (clear area/hole in an area of bacteria where virus has destroyed the cells - result of single cell being infected by single virus, but then virus replicated and infects more cells)
or
Syncytia (virus fuses all the cells around it together eg HIV)
no. of plaques/syncytia can be used to measure how many viral particles were in a sample of virus