Nov 5, 2010

Classification of Viruses

Types of virus Genomes
Forms of DNA from DNA viruses
Cross section of enveloped virus
Intact enveloped virus
Enveloped helical nucleocapsid
Virus Classification
It is based on following points;
  • Nucleic acid type
  • Size and morphology
  • Susceptibilty to chemical and physical agents
  • Viral enzymes
  • Immunological properties
  • Mode of replication
  • Mode of transmission, cell tropisms, pathogenesis and symptomatology
DNA Viruses
  • Parvoviridae
  • Papovaviridae
  1. Papillomavirinae
  2. Polyomavirinae
  • Adenoviridae
  • Herpesviridae
  • Poxviridae
  • Hepadnaviridae

RNA Viruses
  • Picornaviridae
  • Caliciviridae
  • Reoviridae
  • Togaviridae
  • Flaviviridae
  • Arenaviridae
  • Coronaviridae
  • Retroviridae
  • Bunyaviridae
  • Orthomyxoviridae
  • Paramyxoviridae
  • Rhabdoviridae

Bacteriophages are viruses that infect bacteria

Lytic Phage
Phage enter cell, multiply and lyse cell
Example:  T phage of E. coli

Lysogenic Phage
bacteriophage integrate their nucleic acid into genome of the infected host cell (prophage)
Integration of a virus into a cellular genome is termed lysogeny
Example:  lambda phage of E. coli 


Post a Comment