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Viral detection tests&measures
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Transcript of Viral detection tests&measures
![Page 1: Viral detection tests&measures](https://reader035.fdocuments.net/reader035/viewer/2022062503/5873f15a1a28abb1528b5255/html5/thumbnails/1.jpg)
A Viral presentation by S.Vigneshwaran
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Topics to be discussed
• Objectives
• Lab safety
• Specimen collection
• Routine Lab diagnosis
• Newly developed techniques
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OBJECTIVES
Screening
Diagnosis
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Identification
Control of outbreaks
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• Homogenization of infected tissues
• Centrifugation
• Ultrasonic vibration
• Broken glasswares
Common Hazards…
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ingestion..
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Skin penetration..
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Eye
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To be followed….
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Collection of Specimens….
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Oropharyngeal swab
Collection of blood
Nasal swab
Stool collection kit
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Routine lab diagnosisto be carried
M – MicroscopyS – Serological diagnosisV – Viral antigen identification
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Microscopy
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• Virus elementary bodies – Stained smears..
• Electron microscopy efficacy increased
• Viral diarrhea – Electron microscopy only
• Inclusion bodies – Rabies
Vira
l anti
gens
in c
ultu
re
Diag
nosis
Fluo
resc
ent a
ntibo
dy te
chni
que
Direct
Indirect
Examination
Earlydemonstration
Scope
Speed
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Demonstration of virus antigens….
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• Precipitation of gel• Immunofluorescence
• Counterimmunoelectrophoresis• Radioimmunoassay• Enzyme linked immunosorbentassay
• Probe’s method• Polymerase chain reaction
Serological tests
Highly sensitive serological test
Molecular methods
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Sero Diagnosis..
• Rise in titre of antibodies – evidence for causative agent
• For it is essential to examine ‘ A paired sera’
• Collected early in course of disease
Acute sample
• Collected 10 to 14 days later
Convalescent sample
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Serological tests
Employed
depend on….
VirusType of
Generally..• Neutralisation• Complement fixation• ELISA• Haemagglutination inhibition tests
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Molecular diagnosis
availability
Enlarging the scope
sensitivity
specificity Viral
disease
diagnosis
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Newly developed techniques
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ELVIS
Herpes simplex virus
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ᵝ galactosidase production
lac 2 gene gets activated
Activates UL97 Promoter
Hamster kidney cell
HSV
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Nucleic acid amplification• Commercial kits – rapid diagnosis• Amplified NA – easy for detection• Standard technique• Methods: 1)PCR 2)Reverse transcriptase• Viruses like 1)HIV-1 2)Cytomegalovirus 3)Hepatitis virus B and C can be detected
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Nucleic acid hybridization• Sensitive and Selective• Spotted – Nitrocellulose membrane & Viral NA• Denatured – alkali • Hybridized – labelled viral NA fragment• Rota virus – dot hybridization technique
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Measuring the immune response to viral infection
Immunity
Cell mediated
Dermal hypersensitivity
cytotoxicity
Humoral mediated IgG,IgM
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Thank u..