Laboratory diagnosis of vi

1. RECENT ADVANCES IN LABORATORY
DIAGNOSIS OF VIRUSES
 Why does this magnificent applied science which
saves work and makes life easier bring us so little
happiness? The simple answer runs: Because we
have not yet learned to make sensible use of it.’
Dr.Deepak W.Deshkar

2. Overview of diagnostic methods of
virus infection
 In general, diagnostic tests can be grouped
into 3 categories.:
 direct detection
 indirect examination (virus isolation)
 serological methods.

3. Direct detection
 In direct examination, the clinical specimen is
examined directly for the presence of virus particles,
virus antigen or viral nucleic acids.
 Electron Microscopy morphology / immune electron
microscopy
 Light microscopy for histological appearance - e.g.
inclusion bodies
 Antigen detection with immunofluorescence, ELISA
etc.
 Molecular techniques for the direct detection of
viral genomes

4. Indirect examination
 Inoculating the specimen in cell culture, eggs or animals
to cultivate virus: this is called virus isolation.
 Cell Culture - cytopathic effect, haemadsorption,
confirmation by neutralization, interference
immunofluorescence etc.
 Eggs pocks on CAM - haemagglutination, inclusion
bodies
 Animals disease or death confirmation by
neutralization

5. Serological diagnosis
 A serological diagnosis can be made by the
detection of rising titres of antibody between
acute and convalescent stages of infection, or
the detection of IgM.
 In general, the majority of common viral
infections can be diagnosed by serological
methods.

6. Classical Techniques Newer Techniques
1. Complement fixation tests
(CFT)
2. Haemagglutination
inhibition tests
3. Immunofluorescence
techniques (IF)
4. Neutralization tests
5. Single Radial Haemolysis
1. Radioimmunoassay (RIA)
2. Enzyme linked
immunosorbent assay
(ELISA) ,(EIA)
3. Particle agglutination
4. Western Blot (WB)
5. Recombinant
immunoblot assay (RIBA),
line immunoassay (Liatek)
etc.
Serology

7. Ad