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• What is one method of detecting viruses?

  By Electron Microscopy

  
• What is another method of detecting viruses?

  By isolation
• What is a third method of detecting viruses?

  Detection of viral antigens
• What is a fourth method of detecting viruses?

  Detection of viral nucleic acids
• What does electron microscopy allow for in virus detection?

  Direct visualization of the virus
• How can morphology help in virus identification?

  It helps assign unknown viruses to families
• What type of viruses can be detected by electron microscopy?

  Noncultivable viruses may also be detectable
• In which decade was electron microscopy crucial for discovering new virus families?

  Late 1960s
• What are the two general procedures of electron microscopy?

  Negative-stain and thin-section microscopy
• Name one virus detected by electron microscopy.

  Influenza virus
• What is one method of virus isolation?

  Cell culture propagation
• What is another method of virus isolation?

  Animal inoculation
• What is a third method of virus isolation?

  Embryonated egg inoculation
• What is immunofluorescence staining used for?

  Antigen-detection in tissue sections

  
• What is the modification in immunofluorescence staining?

  Tagging antibodies with a fluorochrome
• How is emitted light detected in immunofluorescence staining?

  Using a special microscope with filters
• What is the principle of immunohistochemical staining?

  Similar to immunofluorescence staining
• What tag is used in immunohistochemical staining?

  An enzyme, generally horseradish peroxidase
• What does the enzyme in immunohistochemical staining produce?

  A colored product visible under a microscope
• How long does it take to obtain results from immunohistochemical staining?

  More than 24 hours
• What is the sensitivity of enzyme immunoassays (EIA)?

  Moderate sensitivity
• How many virus particles/mL may be required for positive EIA reactions?

  More than 10^5 virus particles/mL
• What type of assays are mostly used in EIA?

  Solid-phase enzyme immunoassays

  
• What is the format of enzyme immunoassays?

  Direct EIA and Indirect EIA

  
• What does immunochromatography refer to?

  Migration of antigen or complexes through a filter
• How does the labeled antibody function in immunochromatography?

  It binds to the antigen of interest
• What is the purpose of the unlabeled antibody in immunochromatography?

  To immobilize antigen-antibody complexes
• What is the Polymerase Chain Reaction (PCR) used for?

  Enzymatic synthesis of specific DNA sequences

  
• What do the oligonucleotide primers do in PCR?

  Hybridize to opposite strands of DNA
• How long are the oligonucleotide primers typically?

  About 20 residues (20-mers)
• What are the methods of detection of viruses?

  • By Electron Microscopy
  • By isolation
  • Detection of viral antigens
  • Detection of viral nucleic acids

  
• What are the procedures involved in electron microscopy?

  • Negative-stain
  • Thin-section electron microscopy
• What are the types of viral antigen detection methods?

  • Immunofluorescence Staining
  • Immunohistochemical Staining
  • Enzyme Immunoassay (EIA)
  • Immunochromatography

  
• What are the key features of Enzyme Immunoassay (EIA)?

  • Moderate sensitivity
  • Requires more than 10^5 virus particles/mL
  • Solid-phase enzyme immunoassays
  • Formats: Direct EIA and Indirect EIA

  
• What are the steps involved in Polymerase Chain Reaction (PCR)?

  1. Enzymatic synthesis of specific DNA sequences
  2. Use of two oligonucleotide primers
  3. Primers hybridize to opposite strands

  
• What is the significance of detecting virus-specific antibodies?

  • Serological diagnosis
  • Indicates past or current infection
  • Helps in epidemiological studies