Ch. 6.4- Clinical Aspects of Viruses and Prions Flashcards
What is the plaque essay technique
When bacteriophages are put on an agar plate with host cells. The bacteriophages then lyse the host cells during release which leaves a plaque around where the cell was lysed. In theory, counting the plaques can help identify the number of PFUs (plaque forming units) in a given sample. (AKA- how concentrated are the bacteriophages in a give sample)
Define specificity
Means the diagnostic test reliably detects only the viruses of interest without producing false positive results.
Define sensitivity
Means the test detects very low levels of the target to limit false negative results.
Define agglutinate
When antibodies bind to an antigen and bead up.
Define the agglutination test
Method of pathogen detection.
Antibody coated latex beads are mixed with a sample. If the sample contains the viral antigen being sought, the antibodies will agglutinate to the antigen and bead up.
Describe the Enzyme Linked Immunosorbent Assay
Method of pathogen detection.
ELISAs adhere a antibody or antigen to a surface and usually change color if there is binding.
What are flaws in the Agglutination and ELISA tests?
Sample being tested must be liquid and they will not detect anything if there has been antigen shift or antigenic drift in just the right way.
These are also ineffective during early stage infection.
Define seroconversion window
The period of time that it takes for antibodies and antigens to produced in sufficient numbers (following a new infection) for them to be detectible in the Agglutination and ELISA tests.
Describe the Viral Genetic Material test
DNA and RNA are extracted from a clinical sample (sputum, CSF, tissue) Then very specific segments of viral nucleic acid can be detected using florescent tabled probes, by sequencing the nucleic acids or by PCR, that amplify certain parts of the genetic sequence.
Define PCR
Polymerase chain reaction
Define post-exposure prophylaxis
When a patient is injected with a drug that will coat a virus and stop it from binding to host cells.
Define nucleoside analogs
Drugs that block replication
Define nucleoside reverse transcriptase inhibitors
These target reverse transcriptase enzymes
Define nucleoside
This is basically a nucleotide that is missing the phosphate group.
define antisense antivirals
These are short sequences of nucleotides that are complimentary to the RNA transcribed by specific viruses.
