Viral classification

Viruses can be classified in several ways. The most useful is probably by the type of nucleic acid the virus contains, but they can also be classified:

• by their geometry
• by whether they have envelopes
• by the identity of the host organism they can infect
• by mode of transmission
• by the type of disease they cause

Classification by type of constituent nucleic acid (i.e. by genome type), with examples:

• Class I double stranded DNA.
  • Papovavirus
    • Papilloma (human warts, cervical cancer)
    • Polyoma (tumors in certain animals)
  • Adenovirus
    • Respiratory diseases, some cause turmors in certain animals
  • Herpesvirus
    • Herpes simplex I (cold sores)
    • Herpes simplex II (genital herpes)
    • Varicella zoster (chicken pox, shingles)
    • Epstein-Barr virus (mononucleosis, Burkitt's lymphoma)
    • cytomegalovirus
  • Poxvirus
    • Smallpox
    • Vaccinia
    • Cowpox
• Class II single stranded DNA.
  • Parvovirus (most depend on coinfection with adenoviruses for growth)
• Class III double stranded RNA.
  • Reovirus (Diarrhea)
    • Rotavirus
• Class IV positive single stranded RNA itself acting as mRNA.
  • Coronavirus
  • Picornavirus
    • Poliovirus
    • Rhinovirus (common cold)
    • Enteric viruses
  • Togavirus
    • Rubella virus
    • Yellow fever virus
    • Encephalitis viruses
  • hepatitis C virus
• Class V negative single stranded RNA used as a template for mRNA synthesis.
  • Rhabdovirus
    • Rabies
  • Paramyxovirus
    • Measles
    • Mumps
    • human metapneumovirus
    • henipaviruses
  • Orthomyxovirus
    • Influenza viruses
• Class VI positive single stranded RNA with a DNA intermediate in replication.
  • Retrovirus
    • RNA tumor viruses (e.g., leukemia)
    • human immunodeficiency virus (HIV)
• Class VII double stranded DNA with an RNA intermediate in replication.
  • hepatitis B virus