General Principles

• What are the methods for isolation and culture of viruses?

  • Embryonated egg inoculation
  • Cell cultures
  • Inoculation of animals
• What is the age range of embryonated eggs used for inoculation?

  6-12 days
• What is the purpose of drilling a hole in the shell of an embryonated egg?

  To inject viral suspension or tissue
• Which membrane is mainly used for the growth of poxvirus and HSV?

  Chorioallantoic Membrane (CAM)
• How is virus growth in the CAM indicated?

  By visible lesions (pocks)
• What is the most popular method for viral inoculation?

  Allantoic Cavity
• What is the primary use of the Amniotic Cavity?

  Primary isolation of influenza and mumps virus
• How can viral growth in egg embryos be detected?

  By haemagglutination assay
• What indicates viral growth in egg embryos?

  Death of the embryo or lesions
• What is the incubation period for inoculated eggs?

  2-6 days at 33-37°C
• What is harvested from egg liquids for future tests?

  Reaction inhibition of haemagglutination
• What are the types of cell cultures used for virus isolation?

  • Primary cell culture
  • Secondary cell culture
  • Continuous cell lines
  • Monolayer cultures
  • Suspension cultures
• What is a primary cell culture?

  Dissociated cells from parental tissue
• What defines a secondary cell culture?

  Sub-cultured primary culture
• What is a finite cell line?

  Limited number of cell generations
• What is the doubling time for finite cell lines?

  24-96 hours
• What characterizes continuous cell lines?

  Absence of contact inhibition
• What is the doubling time for continuous cell lines?

  12-24 hours
• What is a monolayer culture?

  Single layer of cells in a vessel
• What is a suspension culture?

  Non-adhesive cell growth
• What is a cytopathic effect?

  Visible damage to infected cells
• What is the definition of a virus?

  Small infectious agent replicating in cells
• What are the components of virus particles (virions)?

  Genetic material, protein coat, optional envelope
• What types of nucleic acid can viruses have?

  DNA or RNA
• What are the shapes of viruses?

  Helical, Icosahedral, Complex
• What are the general principles of viral diagnosis?

  • Specimen selection and collection
  • Specimen transport
  • Laboratory diagnosis
  • Viral isolation
  • Serological examination
• What should specimens for viral isolation be collected based on?

  Signs and symptoms
• How should specimens be collected for viral isolation?

  In aseptic conditions
• How should specimens be transported?

  On ice in special medium
• What is the purpose of antibiotics in specimen transport?

  To inhibit bacterial growth
• What methods are used for the observation of viruses?

  Electron, fluorescent, and light microscopy
• What is the specific staining method for intracellular inclusions?

  Romanovski-Giemza staining
• What are Babes-Negri bodies associated with?

  Rabies virus infection
• What are Guarnieri bodies associated with?

  Smallpox virus infection
• What are Owl's eye intranuclear inclusion bodies associated with?

  CMV infection
• What are the methods for inoculation of animals?

  • Subcutaneous
  • Intramuscular
  • Intravenous
  • Intraperitoneal
  • Intracerebral
  • Intranasal
• What are the challenges of inoculating animals for viral studies?

  Ethically controversial and expensive
• Why are some human viruses difficult to culture in animals?

  They may not grow in any animal model
• What is a risk associated with animal inoculation?

  Risk of escaped animals