Page 130 - LECTURE NOTES

1. Indirect examination

a. Cell culture – cytopathic effect, hemadsorption, confirmation by
neutralization, interference, immunofluorescence etc.

b. Animals disease or death confirmation by neutralization
c. Serology; detection of antibody and convalescent stages of infection,

or the detection of IgM in primary infection.

Direct examination of specimen

o Fluoresce in an enzyme or a radiolabel (the indicator system) is
conjugated to the antibody used to detect the virus (Primary antibody)

specifically.

1. Antigen -capture EIA, which is used to detect extra cellular viral antigens
in exudates and homogenized tissues. A common application of antigen

capture, for which several commercial kits are available, is in the
diagnosis of Herpes simplex.

2. Immuno fluorescence (IF) for the detection of infected cells in exudates
and secretions

3. Immuno filtration is a powerful technique for rapid detection of infected

cells in tissue samples
4. Detection for viral DNA or RNA sequences in clinical samples.

For rapid diagnostic purposes, virus-specific nucleic acid sequences in
serum, cells or tissue extracts are detected primarily by dot- blot

hybridization techniques.

Polymerase Chain Reaction is important for virus diagnosis.

It is extremely sensitive and widely regarded as a research tool with limited application
to the diagnostic workbench.

Indirect examination
o The indicator system is conjugated to a secondary antibody, which in turn

directed against the primary antibody.

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