Viral Diagnostics Flashcards
What is CPE?
Cytopathic effect
This term describes viral infections on host cells, such as syncytial cells, rounding up of cells, or viral inclusions.
What is hemadsorption?
RBCs typically stick to infected epithelium which expresses viral proteins.
How is the hemadsorption test modified?
You can add antibodies to the infected epithelium that are specific to a certain virus. If RBCs no longer bind when you add antibodies, then it means that the epithelial cells are likely infected with that virus.
In a 96-well plate, hemagglutination appears as ___________.
a coating of the entire bottom of the well
Rubella virus is in the family ____________.
Togaviridae
True or false: there are roughly 500 cases of Rubella each year.
False. Rubella has actually been eliminated in the Americas. It’s still present in Africa and Asia.
How is RT-PCR done?
Reverse transcriptase gives cDNA from an RNA template. Polymerase then amplifies the cDNA which can be tested for in Southern blotting.
What is a capture ELISA?
A test tube is lined with anti-IgM antibody. Patient serum is then poured over and all IgM will be trapped. Viral antigen is then added and if IgM recognizes it then color change will occur.
How fast is PCR?
In less than one hour the rapid PCR can tell you if any one of 20 pathogens is present.
What must occur for a rapid Strep antigen test to be valid?
The line at C must appear red, otherwise, it could indicate that the sample didn’t elute through the column.
Why are sera taken at different times to evaluate for viral presence?
There are normal “viral flora” that can be present in serum. Thus, samples need to be taken while the patient is ill and healthy to evaluate for whether or not the virus caused the disease.
Western blots are used to evaluate for patient _____________.
antibodies
That is, viral proteins are spread onto a Western gel and then patient serum is incubated on top of it.
How can you determine if a virus has a lipid envelope?
Chloroform and ether will dissolve the lipid membrane and render enveloped viruses inert. Non-enveloped viruses will still be able to infect cells.
If you add RBCs, virus, and patient serum to a 96-well plate and it forms a lattice, then what can you conclude?
That the patient does not have antibodies to the virus.
