Viral Identification Flashcards
what are the 2 rationale for seeking an etiological diagnosis
individual animal / herd level
at state, country and international level
what does the chance of isolating a virus depend on
critically on the vet’s attention to the sample collection
true or false:
samples must be taken at the right place and right time otherwise the sample may give false results
true
true or false:
you should always freeze a sample to preserve is
false
there are very few viruses that can survive in the cold
what are the keys to an ideal viral identification test
sensitive
specific
economic
easy / practical to use
available
fast
define a sensitive test (sensitivity)
percentage of true positives in a herd
define a specific test (specificity)
false positive rate
percentage of healthy animals which test negative by the test divided by the total number of infected animals
what are the 2 ways a virus can be identified / visualized
direct
indirect
what type of identification test is done by visualizing the virus with an electron microscope or by detecting a portion of the virus such as antigen, DNA (nucleic acid or proteins)
direct
what type of identification is done when the virus is grown to amplify or by detecting the host immune response
indirect
in a classical immune electron microscope, what is treated with specific anti-sera
sample
in a solid phase immune electron microscopy, what is treated with specific anti-sera
the grid
true or false:
PCR does not allow in vitro amplification therefore making the test unusable
false
PCR allows in vitro amplification
when the target is an RNA genome, what is needed to amplify the virus
RT-PCR which can copy the RNA into cDNA
what are the advantages to PCR testing
extremely sensitive
easy to set up
fast results
