Term
| Virus Isolation Techniques (4) |
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Definition
Cytopathic Effect
Fluorescent Antibody
Immunocytochemistry
Negative Staining EM |
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Term
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Definition
refers to degenerative changes in cells, especially in tissue culture, and may be associated with the multiplication of certain viruses
cytolysis, synctia formation, inclusion bodies, transformation |
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Term
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Definition
specific anti-virus antibody is labeled with flurochrome
FA conjugate incubated with virally infected cells and if specific virus is present, antibodies will bind to viral proteins and can see special UV light
performed on fresh tissue
need normal and abnormal tissues in sample |
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Term
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Definition
specific anti-virus antibody is labeled with enzyme
conjugate incubated with virally infected cells and if specific virus is present, antibodies will bind to viral proteins and can color changes |
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Term
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Definition
| virus protein does not stain against a black background |
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Term
| Guidelines for Sample Quality |
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Definition
avoid necrotic/autolyzed samples
collect as aseptically as possible
refridgerate at 4C if lung or freeze at -20C
submit ASAP |
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Term
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Definition
detects viral proteins (antigens)
does not require infectious virus
antigen binds to capture antibody in the well
secondary antibody added with enzyme attached to it
secondary antibody binds to antigen-antibody complex
substrate is added to activate enzyme attached to secondary antibody |
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Term
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Definition
true negative
ability of assay to detect particular target instead of others |
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Term
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Definition
true positive
smallest amount of target in sample that can reliably be detected by an assay |
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Term
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Definition
amplification of dsDNA target sequence
pathogen is known
observe results by electrophoresis |
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Term
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Definition
reverse transcriptase PCR
amplification of RNA target sequence
observe results by electrophoresis |
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Term
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Definition
real time PCR
PCR step involves fluorescent probe specific for a target
fluorescence measure during run by spectrophotometer in thermocylcer
the more targets present to amplify, the less cycles required to detect threshold fluorescence
observe results by Ct value |
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Term
| Restriction Fragment Length Polymorphism (RFLP) |
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Definition
old technology
used to determine differences between viruses within a viral group
endonucleases cleave viral genome into fragments
observe results by electrophoresis |
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Term
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Definition
new technology
used to determine differences between viruses within a viral group
amplify template in an open reading frame and determine sequence
determine homology between lab isolates |
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Term
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Definition
ability of host antibodies to specifically bind and effect neutralization of a pathogen
each assay is for a specific virus
virus in assay induces CPE
result is based on whether a dilution of serum sample can block development of CPE which means the animal has neutralizing antibodies and the animal has been infected
Titer=reciprocal of last serum sample dilution that can neutralize the test virus infection
look at acute and convalescent serum samples and see if the titer of the convalescent serum has at least a 4 fold increase |
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Term
| Hemagglutination Inhibition |
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Definition
based on ability of virus to agglutinate RBCs
If the virus is present, it will agglutinate the RBCs and cause it to float
inhibition of agglutination is due to the antibody titer which cause the RBC to pellet and sink
measures all types of antibodies in the serum
Titer=reciprical of last serum dilution that could inhibit the test virus from agglutinating RBCs
look at acute and convalescent serum samples and see if the titer of the convalescent serum has at least a 4 fold increase |
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Term
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Definition
viral antigens are used to detect anti-viral antibodies in the serum sample
positive result indicates exposure of an animal to the virus
FIV - antibodies
FeLV - antigens |
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Term
| Indirect Fluorescent Antibody |
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Definition
| detects antiviral antibodies in a tissue sample |
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Term
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Definition
soluble antibody/antigen placed in a gel well radially diffuses
antibody in the center and dilutions of serum containing antibodies are made around the center
if a line precipitates perpendicular to the well, it is a positive |
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