This document summarizes various laboratory techniques for diagnosing viral infections, including: 1. Electron microscopy, fluorescent microscopy, and light microscopy can directly detect viruses or inclusion bodies caused by viruses in clinical samples like feces, vesicular fluid, or cerebrospinal fluid. 2. Immunoelectron microscopy and viral antigen detection methods like ELISA and latex agglutination can more sensitively detect specific viruses. 3. Nucleic acid detection methods like PCR can identify viruses like HIV, HPV, hepatitis viruses, and enteroviruses. 4. Viruses can also be isolated using animal inoculation, embryonated egg cultivation, tissue culture, or detection of specific antibodies in patient samples.

1. LABORATORY DIAGNOSIS OF VIRAL
INFECTIONS

3. TIMELINE
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5. • Direct demonstration of virus and components
• Isolation of virus
• Detection of specific antibodies

6. ELECTRON MICROSCOPY
Faeces – Rotavirus, Hep A , Adenovirus, Norwalk virus, Astrovirus
Vesicular Fluid – Herpes simplex
CSF – Enterovirus , Varicella Zoster
Urine – Cytomegalovirus

7. IMMUNOELECTRON MICROSCOPY
• Add specific Ab – Increase sensitivity

8. FLUROSCENT MICROSCOPY
RABIES VIRUS IN BRAIN

9. LIGHT MICROSCOPY
• Inclusion Bodies
• Negri bodies – rabies virus in brain tissue

11. VIRAL ANTIGENS
• ELISA, RIA, Latex agglutination

12. NUCLEIC ACID PROBES
• Cytomegalovirus
• Papillomavirus
• Epstein Barr Virus

13. POLYMERASE CHAIN REACTION
• HIV 1 & 2
• HPV
• Herpes Simplex
• Hep B
• Hep C
• Enterovirus
• Rotavirus

14. ISOLATION OF VIRUSES

15. ANIMAL
INOCULATION
• Reed and colleagues – Yellow fever in human
• Landsteiner and Popper – Monkey – Polio
• Mice are widely used by Theiler – 1903
• Suckling mice – coxsackie, arbovirus
• Guinea pigs, rabbits and ferrets are also used

17. EMBRYONATED EGG CULTIVATION
• Good Pasteur - 1931
• Duck eggs better
• Chorioallantoic membrane – vaccinia/variola forms
pocks
• Allantoic cavity – influenza, paramyxovirus isolation
and vaccine production
• Amniotic cavity – influenza virus
• Yolk sac – chlamydiae, rickettsiae, vaccine production
yellow fever (17D strain), rabies (flurry strain)

20. POCK FORMATION

21. TISSUE CULTURE
• Steinhardt 1913 – maintained vaccinia virus in
cornea of Rabbit
• Major Problem in tissue culture – Bacterial
contamination
• After antibiotics – Routinely used
• Enders, Weller, Robbins – grew Polio in non
neural tissue – 1949 (MOST IMP)

22. TISSUE CULTURE
CLASSIFICATION

23. ORGAN CULTURE

24. EXPLANT CULTURE

26. CELL CULTURE

32. Virus-specific CPE in simian kidney cell line LLC-MK2.
Non-inoculated cells (A)
cells inoculated with plasma specimen 1225/2014, 8 days post-inoculation (B)

33. DETECTION OF SPECIFIC ANTIBODIES
• Rise in titre –
Demo
• Detection of IgM
specific antibodies
• Neutralisation ,
ELISA,
Heamagglutination
inhibition,
Complement
fixation Test, IF

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