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
- 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
- Papovavirus
- Class II single stranded DNA.
- Parvovirus (most depend on coinfection with adenoviruses for growth)
- Class III double stranded RNA.
- 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 (Mononegavirales).
- Rhabdovirus
- Paramyxovirus
- Orthomyxovirus
- Influenza viruses
- Bunyaviruses
- Hantaviruses (Hantavirus pulmonary syndrome, Korean Hemorrhagic Fever)
- Arenaviruses
- Class VI positive single stranded RNA with a DNA intermediate in replication.
- Class VII double stranded DNA with an RNA intermediate in replication.
- hepatitis B virus